3437 lines
105 KiB
HTML
3437 lines
105 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>The Unix Hardware Buyer HOWTO</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"></HEAD
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><BODY
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CLASS="article"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="ARTICLE"
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><DIV
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CLASS="TITLEPAGE"
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><H1
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CLASS="title"
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><A
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NAME="AEN2"
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></A
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>The Unix Hardware Buyer HOWTO</H1
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><H3
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CLASS="author"
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><A
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NAME="AEN4"
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>Eric Raymond</A
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></H3
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><DIV
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CLASS="affiliation"
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><DIV
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CLASS="address"
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><P
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CLASS="address"
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><br>
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<TT
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CLASS="email"
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><<A
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HREF="mailto:esr@thyrsus.com"
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>esr@thyrsus.com</A
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>></TT
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><br>
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</P
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></DIV
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></DIV
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><DIV
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CLASS="revhistory"
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><TABLE
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WIDTH="100%"
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BORDER="0"
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><TR
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><TH
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ALIGN="LEFT"
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VALIGN="TOP"
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COLSPAN="3"
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><B
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>Revision History</B
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></TH
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 4.2</TD
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><TD
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ALIGN="LEFT"
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>2010-04-11</TD
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><TD
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ALIGN="LEFT"
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>Revised by: esr</TD
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></TR
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><TR
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||
><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>DVD region-locking firmware is no longer an issue,</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 4.1</TD
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><TD
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ALIGN="LEFT"
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>2009-07-01</TD
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><TD
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ALIGN="LEFT"
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>Revised by: esr</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>DTX failed. Finally deprecate SCSI. 32-bit is dead.
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Avoiding the printer-consumables trap. Invasion of the netbooks.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 4.0</TD
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><TD
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ALIGN="LEFT"
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>2007-11-02</TD
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><TD
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ALIGN="LEFT"
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>Revised by: esr</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Major revisions by Jonathan Marsden on SATA, bus standards,
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DVDs and other topics, followed by a cleanup pass from me.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 3.3</TD
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><TD
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ALIGN="LEFT"
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>2007-18-13</TD
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><TD
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ALIGN="LEFT"
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>Revised by: esr</TD
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></TR
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><TR
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><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
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>Updated for 2007 conditions. CRTs are dead. BTX is
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dead. CD-ROMs are competely generic now. USB modems are
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||
recommended.</TD
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></TR
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><TR
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><TD
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||
ALIGN="LEFT"
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||
>Revision 3.2</TD
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><TD
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||
ALIGN="LEFT"
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||
>2004-10-28</TD
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><TD
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||
ALIGN="LEFT"
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||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
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>Fix and remove bad links.</TD
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||
></TR
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><TR
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||
><TD
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||
ALIGN="LEFT"
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||
>Revision 3.1</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2004-08-03</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
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||
>Sound cards don't matter any more.</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revision 3.0</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2004-02-21</TD
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||
><TD
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||
ALIGN="LEFT"
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||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
|
||
COLSPAN="3"
|
||
>Power-protection stuff moved to UPS HOWTO. DIMM memory is
|
||
gone. Tape drives don't make sense any more. Lots of the
|
||
theory from my "Ultimate Linux Box"
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||
articles now lives here.</TD
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||
></TR
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||
><TR
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>Revision 2.4</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2003-02-22</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
|
||
>URL fixes.</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revision 2.3</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2002-08-06</TD
|
||
><TD
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||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
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||
>Buying at the low end isn't a lose anymore. I recommend
|
||
Athlons. Nuked the section on video standards, EDID takes
|
||
care of all that now. Also removed the section on older
|
||
memory types. And keyboards, as the "ergonomic" ones all
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||
vanished along with the 1990s carpal-tunnel scare.</TD
|
||
></TR
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||
><TR
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||
><TD
|
||
ALIGN="LEFT"
|
||
>Revision 2.2</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2002-08-05</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
COLSPAN="3"
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||
>New section on DVD drives.</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
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||
>Revision 2.1</TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>2002-07-08</TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
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||
><TR
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||
><TD
|
||
ALIGN="LEFT"
|
||
COLSPAN="3"
|
||
>Corrected Kingston URL. Various small updates for the last
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||
year. This HOWTO is much more stable than it used to be.</TD
|
||
></TR
|
||
><TR
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>Revision 2.0</TD
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||
><TD
|
||
ALIGN="LEFT"
|
||
>2001-08-09</TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
|
||
><TR
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||
><TD
|
||
ALIGN="LEFT"
|
||
COLSPAN="3"
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||
>Major update. Revisions based on Ultimate Linux Box experience.
|
||
Caches are on-chip now. DDS4 tape drives are here.
|
||
486 machines, CD caddies, and most non-DDS backup
|
||
technologies are gone.</TD
|
||
></TR
|
||
><TR
|
||
><TD
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||
ALIGN="LEFT"
|
||
>Revision 1.1</TD
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||
><TD
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||
ALIGN="LEFT"
|
||
>2001-06-13</TD
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||
><TD
|
||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
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||
></TR
|
||
><TR
|
||
><TD
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||
ALIGN="LEFT"
|
||
COLSPAN="3"
|
||
>Mid-2001 update.</TD
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||
></TR
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||
><TR
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||
><TD
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||
ALIGN="LEFT"
|
||
>Revision 1.0</TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>2001-02-06</TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
>Revised by: esr</TD
|
||
></TR
|
||
><TR
|
||
><TD
|
||
ALIGN="LEFT"
|
||
COLSPAN="3"
|
||
>Initial revision; but see the history in the introduction.</TD
|
||
></TR
|
||
></TABLE
|
||
></DIV
|
||
><DIV
|
||
><DIV
|
||
CLASS="abstract"
|
||
><A
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||
NAME="AEN10"
|
||
></A
|
||
><P
|
||
></P
|
||
><P
|
||
> This is your one-stop resource for information about how to buy and
|
||
configure generic PC hardware for cheap, powerful Unix systems.
|
||
</P
|
||
><P
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||
></P
|
||
></DIV
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||
></DIV
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||
><HR></DIV
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||
><DIV
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||
CLASS="TOC"
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||
><DL
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||
><DT
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||
><B
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||
>Table of Contents</B
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||
></DT
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||
><DT
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||
>1. <A
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||
HREF="#intro"
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||
>Introduction</A
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||
></DT
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||
><DD
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||
><DL
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||
><DT
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||
>1.1. <A
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||
HREF="#purpose"
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||
>Purpose of this document</A
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||
></DT
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||
><DT
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||
>1.2. <A
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||
HREF="#newversions"
|
||
>New versions of this document</A
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||
></DT
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||
><DT
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||
>1.3. <A
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||
HREF="#feedback"
|
||
>Feedback and corrections</A
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||
></DT
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||
><DT
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||
>1.4. <A
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||
HREF="#resources"
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||
>Related resources</A
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||
></DT
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||
></DL
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||
></DD
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||
><DT
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||
>2. <A
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||
HREF="#overview"
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||
>Overview of the Market</A
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||
></DT
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||
><DT
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||
>3. <A
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||
HREF="#basics"
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||
>Buying the Basics</A
|
||
></DT
|
||
><DD
|
||
><DL
|
||
><DT
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||
>3.1. <A
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||
HREF="#AEN132"
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||
>Things to Not Care About</A
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||
></DT
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||
><DT
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||
>3.2. <A
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||
HREF="#processor"
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||
>How To Pick Your Processor</A
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||
></DT
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||
><DT
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||
>3.3. <A
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||
HREF="#twospindles"
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||
>One Disk or Two?</A
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||
></DT
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||
><DT
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||
>3.4. <A
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||
HREF="#cases"
|
||
>Getting Down to Cases</A
|
||
></DT
|
||
><DT
|
||
>3.5. <A
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||
HREF="#power"
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||
>Power Supplies and Fans</A
|
||
></DT
|
||
><DT
|
||
>3.6. <A
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||
HREF="#motherboards"
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||
>Motherboards</A
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||
></DT
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||
><DT
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||
>3.7. <A
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||
HREF="#AEN238"
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||
>Monitor and Video</A
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||
></DT
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||
><DT
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||
>3.8. <A
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||
HREF="#dvd"
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||
>DVD Drives</A
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||
></DT
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||
><DT
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||
>3.9. <A
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||
HREF="#sound"
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>Sound Cards and Speakers</A
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||
></DT
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||
><DT
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||
>3.10. <A
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||
HREF="#modems"
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||
>Modems</A
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||
></DT
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||
><DT
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||
>3.11. <A
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||
HREF="#printers"
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||
>Printers</A
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||
></DT
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||
><DT
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||
>3.12. <A
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||
HREF="#power_protection"
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||
>Power Protection</A
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||
></DT
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||
><DT
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||
>3.13. <A
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||
HREF="#rfi"
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||
>Radio Frequency Interference</A
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||
></DT
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||
></DL
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||
></DD
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||
><DT
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||
>4. <A
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||
HREF="#optimize"
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||
>What To Optimize</A
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||
></DT
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||
><DD
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||
><DL
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||
><DT
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||
>4.1. <A
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||
HREF="#AEN378"
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||
>First, add more memory</A
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||
></DT
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||
><DT
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||
>4.2. <A
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||
HREF="#AEN381"
|
||
>Bus and Disk speeds</A
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||
></DT
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||
><DT
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||
>4.3. <A
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||
HREF="#diskwars"
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||
>Optimizing your disk subsystem</A
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||
></DT
|
||
><DT
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||
>4.4. <A
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||
HREF="#iotune"
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||
>Tuning Your I/O Subsystem</A
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||
></DT
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||
></DL
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||
></DD
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||
><DT
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||
>5. <A
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||
HREF="#economizing"
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||
>But What If I'm Economizing?</A
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||
></DT
|
||
><DT
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||
>6. <A
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||
HREF="#noise"
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||
>Noise Control and Heat Dissipation</A
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||
></DT
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||
><DT
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||
>7. <A
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||
HREF="#laptops"
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||
>Special Considerations When Buying Laptops and Netbboks</A
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||
></DT
|
||
><DT
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||
>8. <A
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||
HREF="#howtobuy"
|
||
>How to Buy</A
|
||
></DT
|
||
><DD
|
||
><DL
|
||
><DT
|
||
>8.1. <A
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||
HREF="#whentobuy"
|
||
>When to Buy</A
|
||
></DT
|
||
><DT
|
||
>8.2. <A
|
||
HREF="#wheretobuy"
|
||
>Where to Buy</A
|
||
></DT
|
||
><DT
|
||
>8.3. <A
|
||
HREF="#fairs"
|
||
>Computer Fairs</A
|
||
></DT
|
||
><DT
|
||
>8.4. <A
|
||
HREF="#mailorder"
|
||
>Mail Order</A
|
||
></DT
|
||
><DT
|
||
>8.5. <A
|
||
HREF="#superstores"
|
||
>Computer Superstores</A
|
||
></DT
|
||
><DT
|
||
>8.6. <A
|
||
HREF="#buying_tips"
|
||
>Other Buying Tips</A
|
||
></DT
|
||
></DL
|
||
></DD
|
||
><DT
|
||
>9. <A
|
||
HREF="#questions"
|
||
>Questions You Should Always Ask Your Vendor</A
|
||
></DT
|
||
><DD
|
||
><DL
|
||
><DT
|
||
>9.1. <A
|
||
HREF="#warranty"
|
||
>Minimum Warranty Provisions</A
|
||
></DT
|
||
><DT
|
||
>9.2. <A
|
||
HREF="#documention"
|
||
>Documentation</A
|
||
></DT
|
||
><DT
|
||
>9.3. <A
|
||
HREF="#quality"
|
||
>A System Quality Checklist</A
|
||
></DT
|
||
></DL
|
||
></DD
|
||
><DT
|
||
>10. <A
|
||
HREF="#mailtips"
|
||
>Things to Check when Buying</A
|
||
></DT
|
||
><DD
|
||
><DL
|
||
><DT
|
||
>10.1. <A
|
||
HREF="#tricks"
|
||
>Tricks and Traps in Warranties</A
|
||
></DT
|
||
><DT
|
||
>10.2. <A
|
||
HREF="#mail_questions"
|
||
>Special Questions to Ask Web/Mail-Order
|
||
Vendors Before Buying</A
|
||
></DT
|
||
><DT
|
||
>10.3. <A
|
||
HREF="#payment"
|
||
>Payment Method</A
|
||
></DT
|
||
><DT
|
||
>10.4. <A
|
||
HREF="#vendors"
|
||
>Which Clone Vendors to Talk To</A
|
||
></DT
|
||
></DL
|
||
></DD
|
||
><DT
|
||
>11. <A
|
||
HREF="#AEN675"
|
||
>After You Take Delivery</A
|
||
></DT
|
||
><DT
|
||
>12. <A
|
||
HREF="#software"
|
||
>Software to go with your hardware</A
|
||
></DT
|
||
><DT
|
||
>13. <A
|
||
HREF="#links"
|
||
>Other Resources on Building Linux PCs</A
|
||
></DT
|
||
></DL
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="intro"
|
||
></A
|
||
>1. Introduction</H1
|
||
><DIV
|
||
CLASS="sect2"
|
||
><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="purpose"
|
||
></A
|
||
>1.1. Purpose of this document</H2
|
||
><P
|
||
>The purpose of this document is to give you the background
|
||
information you need to be a savvy buyer of Intel hardware for running
|
||
Unix. It is aimed especially at hackers and others with the technical
|
||
skills and confidence to go to the Internet/mail-order channel, but
|
||
contains plenty of useful advice for people buying store-front
|
||
retail.</P
|
||
><P
|
||
>This document is maintained and periodically updated as a service to
|
||
the net by Eric S. Raymond, who began it for the very best self-interested
|
||
reason that he was in the market and didn't believe in plonking down
|
||
several grand without doing his homework first (no, I don't get paid for
|
||
this, though I have had a bunch of free software and hardware dumped on me
|
||
as a result of it!). Corrections, updates, and all pertinent information
|
||
are welcomed at <A
|
||
HREF="mailto:esr@snark.thyrsus.com"
|
||
TARGET="_top"
|
||
>esr@snark.thyrsus.com</A
|
||
>. The
|
||
editorial <20>we’ reflects the generous contributions of many
|
||
savvy Internetters.</P
|
||
><P
|
||
>If you email me questions that address gaps in the FAQ material,
|
||
you will probably get a reply that says <SPAN
|
||
CLASS="QUOTE"
|
||
>"Sorry, everything I know
|
||
about this topic is in the HOWTO"</SPAN
|
||
>. If you find out the
|
||
<EM
|
||
>answer</EM
|
||
> to such a question, please share it with
|
||
me for the HOWTO, so everyone can benefit.</P
|
||
><P
|
||
>If you end up buying something based on information from this HOWTO,
|
||
please do yourself and the net a favor; make a point of telling the vendor
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"The HOWTO sent me"</SPAN
|
||
> or some equivalent. If we can show
|
||
vendors that this HOWTO influences a lot of purchasing decisions, we get
|
||
leverage to change some things that need changing.</P
|
||
><P
|
||
>Note that in December 1996 I published an introductory article on
|
||
building and tuning Linux systems summarizing much of the material in this
|
||
HOWTO. It's <A
|
||
HREF="http://www.catb.org/~esr/writings/lj-howtobuild.html"
|
||
TARGET="_top"
|
||
>available
|
||
here</A
|
||
>. In 2001 I published an article on building the <A
|
||
HREF="http://www.catb.org/~esr//writings/ultimate-linux-box/"
|
||
TARGET="_top"
|
||
>Ultimate Linux
|
||
Box</A
|
||
>.</P
|
||
><P
|
||
>This Buyer's Guide actually dates back to 1992, when it was known as
|
||
the <SPAN
|
||
CLASS="QUOTE"
|
||
>"PC-Clone Unix Hardware Buyer's Guide"</SPAN
|
||
>; this was before Linux
|
||
took over my world :-). Before that, portions of it were part of
|
||
a Unix Buyer's Guide that I maintained back in the 1980s on USENET.</P
|
||
><P
|
||
>It may be a matter of historical interest that the page count of this
|
||
guide peaked in mid-2001 and has been declining since. Video, sound, and
|
||
other functions are migrating onto motherboards. Several bus types have
|
||
disappeared, as have all the old-school backup technologies that couldn't
|
||
scale up to match disk capacities, Spec sheets are getting
|
||
simpler. Accordingly, there are parts that used to have whole sections to
|
||
hemselves that I barely even write about anymore — mice, floppy disks,
|
||
CD-ROM drives, and keyboards, for example, are utterly generic now,</P
|
||
><P
|
||
>Another consequence of the technology stabilizing is also that I'm
|
||
updating this guide less often than I used to. Years can now go by without
|
||
the PC market changing in any fundamental way. </P
|
||
><P
|
||
>In retrospect, the success of the ATX standard for motherboards in
|
||
1998-1999 was probably the turning point. The PC industry has become
|
||
sufficiently commoditized that your choices are now getting simpler rather
|
||
than more complicated. This is a Good Thing.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="newversions"
|
||
></A
|
||
>1.2. New versions of this document</H2
|
||
><P
|
||
>New versions of the Unix Hardware Buyer HOWTO will be periodically be
|
||
uploaded to various Linux WWW and FTP sites, including the LDP home
|
||
page.</P
|
||
><P
|
||
>You can view the latest version of this on the World Wide Web via the
|
||
URL <A
|
||
HREF="http://www.tldp.org/HOWTO/Unix-Hardware-Buyer-HOWTO/"
|
||
TARGET="_top"
|
||
>http://www.tldp.org/HOWTO/Unix-Hardware-Buyer-HOWTO/</A
|
||
>.
|
||
</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="feedback"
|
||
></A
|
||
>1.3. Feedback and corrections</H2
|
||
><P
|
||
>If you have questions or comments about this document, please
|
||
feel free to mail Eric S. Raymond, at <A
|
||
HREF="mailto:esr@thyrsus.com"
|
||
TARGET="_top"
|
||
> esr@thyrsus.com</A
|
||
>. I welcome any
|
||
suggestions or criticisms. If you find a mistake with this document,
|
||
please let me know so I can correct it in the next
|
||
version. Thanks.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="resources"
|
||
></A
|
||
>1.4. Related resources</H2
|
||
><P
|
||
>You may also want to look at the read the <A
|
||
HREF="http://www.tldp.org/HOWTO/Hardware-HOWTO.html"
|
||
TARGET="_top"
|
||
>Hardware-HOWTO</A
|
||
>. It lists hardware
|
||
known to be compatible with Linux, and hardware known to be
|
||
incompatible. I've also done a series of articles on <A
|
||
HREF="http://www.catb.org/~esr//writings/ultimate-linux-box/"
|
||
TARGET="_top"
|
||
>The Ultimate Linux
|
||
Box</A
|
||
>.</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="overview"
|
||
></A
|
||
>2. Overview of the Market</H1
|
||
><P
|
||
>The central fact about PC hardware is that de-facto hardware
|
||
standards have created a commodity market with low entry barriers, lots of
|
||
competitive pressure, and volume high enough to amortize a
|
||
<EM
|
||
>lot</EM
|
||
> of development on the cheap.</P
|
||
><P
|
||
>The result is that this hardware gives you lots of
|
||
bang-per-buck, and it's getting both cheaper and better all the time.
|
||
Furthermore, margins are thin enough that vendors have to be lean,
|
||
hungry, and <EM
|
||
>very</EM
|
||
> responsive to the market to
|
||
survive.</P
|
||
><P
|
||
>One good general piece of advice is that you should avoid
|
||
the highest-end new-technology systems (those not yet shipping in
|
||
volume). The problem with the high end is that it usually
|
||
carries a hefty <SPAN
|
||
CLASS="QUOTE"
|
||
>"prestige"</SPAN
|
||
> price premium, and may be a bit less
|
||
reliable on average because the technology hasn't been through a lot
|
||
of test/improve cycles.</P
|
||
><P
|
||
>There used to be a real issue with low-end PCs as well,
|
||
because there used to be a lot of dodgy crap PC components out
|
||
there going into boxes made by vendors trying to save a few cents.
|
||
That's not really a problem anymore. Market pressure has been
|
||
very effective at raising reliability standards for even low-end
|
||
components as the market has matured. It's actually hard to go
|
||
wrong even buying at the bottom end of the market these days.</P
|
||
><P
|
||
>I put together the first version of this guide around 1992;
|
||
Unix-capable systems are now ten to twenty times cheaper than they were
|
||
then. At today's prices, building your own system from parts no
|
||
longer makes much sense at all —so this HOWTO is now more oriented
|
||
towards helping you configure a whole system from a single vendor.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="basics"
|
||
></A
|
||
>3. Buying the Basics</H1
|
||
><P
|
||
>In this section, we cover things to look out for that are more or less
|
||
independent of price-performance tradeoffs, part of your minimum system
|
||
for running Unix.</P
|
||
><P
|
||
>Issues like your choice of disk, processor, and I/O bus (where there is
|
||
a significant tradeoff between price and capability) are covered in the section
|
||
on <A
|
||
HREF="#optimize"
|
||
>What To Optimize</A
|
||
>.</P
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="AEN132"
|
||
></A
|
||
>3.1. Things to Not Care About</H2
|
||
><P
|
||
>An effect of PC commoditization is that there aren lots of things
|
||
you used to have to worry about that don't matter any more, because
|
||
the market has completely flattened out. We list these here to get them
|
||
out of the way.</P
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="buswars"
|
||
></A
|
||
>3.1.1. Bus Wars</H3
|
||
><P
|
||
>The system bus is what ties all the parts of your machine together.
|
||
This is an area in which progress has simplified your choices a lot. There
|
||
used to be no fewer than <EM
|
||
>four</EM
|
||
> competing bus standards
|
||
out there (ISA, EISA, VESA/VLB, PCI, and PCMCIA). Now there are
|
||
effectively just <EM
|
||
>two</EM
|
||
> —PCI-X on servers, and PCIe
|
||
for desktop/tower machines. Even PCI is now legacy technology, and the
|
||
PCMCIA bus that seemed so important a few years back has been reduced to
|
||
near-irrelevance by Ethernet, USB, and WiFi hardware built onto
|
||
motherboards. The newcomer is PCIe, which is (in late 2007) a
|
||
‘video-card-mostly’ bus, though it seems to be gaining in
|
||
popularity for other uses too on mainstream desktop motherboards, whereas
|
||
PCI-X is only found on higher end ‘server’ motherboards.
|
||
|
||
</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="memory"
|
||
></A
|
||
>3.1.2. Memory</H3
|
||
><P
|
||
>Judging the memory-controller and cache design used to be one of the
|
||
trickiest parts of evaluating a motherboard, but that stuff is all baked
|
||
into the processor itself now. This removed a large source of latency and
|
||
design variations. It also killed off the plethora of different RAM
|
||
types that used to be out there.</P
|
||
><P
|
||
>Today's advice is very simple. Make sure the memory is rated for your
|
||
machine's bus speed, then buy as much as you can afford to stuff in your
|
||
machine.</P
|
||
><DIV
|
||
CLASS="note"
|
||
><P
|
||
></P
|
||
><TABLE
|
||
CLASS="note"
|
||
WIDTH="100%"
|
||
BORDER="0"
|
||
><TR
|
||
><TD
|
||
WIDTH="25"
|
||
ALIGN="CENTER"
|
||
VALIGN="TOP"
|
||
><IMG
|
||
SRC="../images/note.gif"
|
||
HSPACE="5"
|
||
ALT="Note"></TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
VALIGN="TOP"
|
||
><P
|
||
>DDR3 RAM is beginning to appear. Right now its extra expense
|
||
over DDR2 is not worth paying, for all but extremely specialized needs. It
|
||
is almost always <EM
|
||
>far</EM
|
||
> more useful to have 4GB of
|
||
reasonably fast RAM, than 2GB of very fast RAM, in your
|
||
machine.</P
|
||
></TD
|
||
></TR
|
||
></TABLE
|
||
></DIV
|
||
><P
|
||
>For more technical stuff on memory architectures, see <A
|
||
HREF="http://www.kingston.com/tools/umg/default.asp"
|
||
TARGET="_top"
|
||
>The Ultimate Memory
|
||
Guide</A
|
||
> maintained by Kingston Technologies.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="mice"
|
||
></A
|
||
>3.1.3. Keyboards and Mice</H3
|
||
><P
|
||
>Keyboards are mostly generic nowadays. One useful piece of advice is
|
||
to not buy any desktop machine with <SPAN
|
||
CLASS="QUOTE"
|
||
>"Internet"</SPAN
|
||
> buttons on it;
|
||
this is a sure sign of a PC that's an overpriced glitzy toy. Nowadays
|
||
keyboards with a USB connector are the norm, rather than the older
|
||
dedicated connectors; modern open-source Unixes handle these
|
||
just fine.</P
|
||
><P
|
||
>Mice and trackballs used to be simple; then, thanks to Microsoft,
|
||
they got complicated. Now they're simple again. Again, USB mice have
|
||
replaced the older PS/2-style dedicated connector. XFree86 autodetects
|
||
your mouse when it starts up, so configuration is not a big deal any
|
||
more.</P
|
||
><P
|
||
>Some PC vendors, being Windows-oriented, still bundle two-button
|
||
mice. Thus, you may have to buy your own three-button (or two button and a
|
||
scroll wheel) mouse. Ignore the adspeak about dpi and pick a mouse or
|
||
trackball that feels good to your hand.</P
|
||
><P
|
||
>Your humble editor really, really likes the Logitech TrackMarble, an
|
||
optical trackball that eliminates the chronic roller-fouling problems of
|
||
the older TrackMan. They're well-supported by X, so any Linux or BSD will
|
||
accept them.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="floppies"
|
||
></A
|
||
>3.1.4. Floppy Drives</H3
|
||
><P
|
||
>There's no longer much to be said about floppy drives. They're
|
||
cheap, they're generic, and the rise of CD-ROM and DVD-ROM drives as a
|
||
cheap distribution medium has made them much less important than formerly.
|
||
You only ever see the 3.5-inch ‘hard-shell’ floppies with
|
||
1.44MB capacity anymore.</P
|
||
><P
|
||
>Bootable CD-ROMs killed off the last use of floppies, which was OS
|
||
installation. So go ahead and settle for cheap Mitsumi and Teac floppy
|
||
drives. There are no ‘premium’ floppy drives anymore. Nobody
|
||
bothers.</P
|
||
><P
|
||
>It's possible your system won't even include one. No loss.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="cdrom"
|
||
></A
|
||
>3.1.5. CD-ROM Drives</H3
|
||
><P
|
||
>Standard CD-ROMs hold about 650 megabytes of read-only data in a
|
||
format called ISO-9660 (formerly <SPAN
|
||
CLASS="QUOTE"
|
||
>"High Sierra"</SPAN
|
||
>). All current
|
||
Unixes support these devices. Unix and Linux software is now distributed
|
||
on ISO-9660 CD-ROM, a cheaper and better method than the QIC tapes we used
|
||
to use.</P
|
||
><P
|
||
>CD-ROM speed used to be a big deal; vendors advertised 2X, 4X, all
|
||
the way up to 52X. Vendors don't bother any more; the drives are all about
|
||
equivalently fast now.</P
|
||
><P
|
||
>There are one or two minor features to watch for. Most CD-ROMS will
|
||
include a headphone jack so you can play audio CDs on them. Better-quality
|
||
ones will also include two RCA jacks for use with speakers. Another
|
||
feature to look for is a drive door or seal that protects the drive head
|
||
from dust.</P
|
||
><P
|
||
>Increasingly, DVD-ROM drives (and burners) are replacing CD-ROM drives
|
||
as the default optical drive in PC systems. They have significantly larger
|
||
capacity, and will read (and burn) CD media too. The cost difference now
|
||
is so small that it is usually preferable to buy a DVD burner instead of
|
||
a CD-ROM drive.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="backup"
|
||
></A
|
||
>3.1.6. Backup devices</H3
|
||
><P
|
||
>It's good to be able to make backups that you can separate from your
|
||
system and store off-site in case of disaster. Until about 2001, tape
|
||
drives still seemed like a good idea for personal systems, but I found I
|
||
seldom used mine. Today, tape drives with high enough capacity to image
|
||
today's huge hard disks are too expensive to make sense any more.</P
|
||
><P
|
||
>For the money you'd spend on a high-capacity tape drive (over $1000)
|
||
it makes more sense to buy a laptop and a pile of CD-R or DVD-R or DVD+R
|
||
media. Sit the laptop on your house Ethernet when you're not traveling, and
|
||
back up the main machine to it every day, or oftener. Between the
|
||
efficiency of rsync and the speed of 100-megabit Ethernet, this will be a
|
||
lot faster than making a tape. Every once in a while, burn a set of backup
|
||
CD-ROMs or DVDROMs.</P
|
||
><P
|
||
>But CD-ROMs aren't reusable; the cost piles up over time. An
|
||
interesting alternative is a small external USB hard drive, especially if
|
||
you can salvage an old laptop drive and put it in a USB enclosure. These
|
||
enclosures are available for about $30; Google for "USB HD Enclosure". This
|
||
is faster than a tape, cheaper and lighter than a full laptop. For faster
|
||
transfer speeds, an enclosure that accepts eSATA connections as well as USB
|
||
helps a lot (assuming your PC or notebook has an eSATA connector).</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="processor"
|
||
></A
|
||
>3.2. How To Pick Your Processor</H2
|
||
><P
|
||
>Right now (early 2010), the chips to consider for running Unix are
|
||
the the 64-bit AMD Opteron or its Intel equivalents, especially the Core 2
|
||
Duo. We're long past the point at which 32-bit chips are interesting for
|
||
new desktop systems, presuming you could even find one. AMD and Intel built
|
||
up a buffer before switching their fabs fully to 64-bit chips in 2006, and
|
||
the 32-bit chips you can still find are coming out of warehouses rather
|
||
than off production lines.</P
|
||
><P
|
||
>Brands don't matter much, so don't feel you need to pay Intel's
|
||
premiums if you see an attractive Cyrix, AMD or other chip-clone
|
||
system offered. In the last few years I've been a big fan of
|
||
the AMD line. They used to be faster, cheaper, and better-designed than
|
||
Intel processors; today Intel has clawed back the speed advantage, but
|
||
AMD chips still deliver more performance than you're likely to be able
|
||
to use and do it with lower power dissipation (thus, less noise and
|
||
heat).</P
|
||
><P
|
||
>On the other hand, Intel-chip motherboards now have the advantage
|
||
that the on-board graphics chip will give you 3D acceleration with fully
|
||
open-source drivers. This will avoid the problems you would otherwise face
|
||
trying to select a supported graphics card from ATI or Nvidia.</P
|
||
><P
|
||
>Many CPUs now are multi-core — that is, they have multiple CPUs
|
||
on a single chip. This is very useful for doing something compute
|
||
intensive (re-encoding video, compressing large archives, etc.) in the
|
||
background and still having a responsive system for other work at the same
|
||
time. At current prices, a dual-core CPU makes good sense for most desktop
|
||
systems. If you are building a server or have specialized computing needs
|
||
you expect to be very CPU-intensive quad-core is worth considering, but on
|
||
a desktop system all the two extra cores will usually do is emit heat. Only
|
||
at the very low end (sub US$50 CPUs) do single-core CPUs still make sense
|
||
on desktop machines.</P
|
||
><P
|
||
>Mainstream desktop CPUs now use one of two sockets: LGA 775 (Intel)
|
||
and AM2 (AMD). Buying a system that uses one of these stands more chance
|
||
of allowing a useful CPU upgrade to extend its useful life than systems
|
||
using other less common sockets.</P
|
||
><P
|
||
>Current CPUs are <EM
|
||
>much</EM
|
||
> faster than those of just
|
||
a few years ago. As a result, unless your needs are highly specialized,
|
||
spending more than about US$200 on a desktop CPU is hard to justify. For
|
||
most users, putting extra budget into more RAM or a faster disk subsystem
|
||
will most likely result in greater benefit.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="twospindles"
|
||
></A
|
||
>3.3. One Disk or Two?</H2
|
||
><P
|
||
>I usually build with two disks — one <SPAN
|
||
CLASS="QUOTE"
|
||
>"system"</SPAN
|
||
> disk
|
||
and one <SPAN
|
||
CLASS="QUOTE"
|
||
>"home"</SPAN
|
||
> disk. There are two good reasons to do this
|
||
that have nothing to do with the extra capacity. One of them is the
|
||
performance advantage of being able to interleave commands to different
|
||
physical spindles that we'll explain a bit later in the section on disks.
|
||
The other is that I am quite a bit less likely to lose two disks at once
|
||
than I am to trash a single one.</P
|
||
><P
|
||
>Let's suppose you have a fatal disk crash. If you have only one
|
||
disk, goodbye Charlie. If you have two, maybe the crashed one was your
|
||
system disk, in which case you can buy another and mess around with a new
|
||
Linux installation knowing your personal files are safe. Or maybe it was
|
||
your home disk; in that case, you can still run and do recovery stuff and
|
||
basic Net communications until you can buy another home disk and restore it
|
||
from backups (you <EM
|
||
>did</EM
|
||
> keep backups, right?).</P
|
||
><P
|
||
>Given today's high capacity drives, another way to use two disks well
|
||
is to set them up as a RAID1 (mirrored) array. This can be done in
|
||
software or with a hardware RAID controller. This way if either of the two
|
||
drives fail, the system will continue to function, no data is lost, and
|
||
upon replacing the failed drive, the array can be rebuilt from the
|
||
remaining working drive. Hard drives are consumable media, they
|
||
<EM
|
||
>do</EM
|
||
> fail, so this approach (as well as good backups) is
|
||
well worth considering.</P
|
||
><P
|
||
>Buy SATA. The older IDE and EIDE buses are now obsolete, and SCSI no
|
||
longer has enough of a cost advantage to justify the premium. In fact, SCSI
|
||
has effectively nerged into SCSI; SATA is SCSI commands being shipped over
|
||
a single-wire data line.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="cases"
|
||
></A
|
||
>3.4. Getting Down to Cases</H2
|
||
><P
|
||
>I used to say that cases are just bent metal, and that it doesn't
|
||
much matter who makes those. Unfortunately, this isn't true any more.
|
||
Processors run so hot these days that fans and airflow are a serious
|
||
concern. They need to be well designed for proper airflow
|
||
throughout. </P
|
||
><P
|
||
>Look for the following quality features:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>Aluminum rather than steel. It's lighter and conducts
|
||
heat better.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Unobstructed air intake with at least one fan each
|
||
(in addition to the power supply and processor fans)</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>No sharp metal edges. You don't want to shred
|
||
your hands when you're tinkering with things.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>There shouldn't be any hot spots (poor air flow).</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Sturdy card clips. Some poorly-designed cases allow cards
|
||
to wiggle out of their slots under normal vibration.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Effective and easy to use mechanisms for attaching hard
|
||
drives, CD-ROM, CD-R/W, DVDs, etc.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>If you're fussy about RFI (Radio-Frequency Interference), it's worth
|
||
finding out whether the plastic parts of the case have conductive coating
|
||
on the inside; that will cut down emissions significantly, but a few cheap
|
||
cases omit it.</P
|
||
><P
|
||
>Should you buy a desktop or tower case? Our advice is go with tower
|
||
unless you're building a no-expansions personal system and expect to be
|
||
using the floppies a lot. Many vendors charge nothing extra for a tower
|
||
case, and the cost difference will be trivial even if they do. What you
|
||
get for that is less desktop clutter, more and bigger bays for expansion,
|
||
and often (perhaps most importantly) a beefed-up power-supply and fan.
|
||
Putting the box and its fan under a table is good for maybe 5db off the
|
||
effective noise level, too. Airflow is also an issue; if the peripheral
|
||
bays are less cramped, you get better cooling. Be prepared to buy
|
||
extension cables for your keyboard and monitor, though; vendors almost
|
||
never include enough flex.</P
|
||
><P
|
||
>The airflow thing is a good argument for a full- or mid-tower rather
|
||
than the ‘baby tower’ cases some vendors offer. However, smaller
|
||
towers are getting more attractive as boards and devices shrink and
|
||
more functions migrate onto the motherboard. A state of the art
|
||
system, with all 3" disks, 300W power supply, half-size motherboard,
|
||
on-board SATA and 4GB of RAM sockets, and half-sized expansion cards,
|
||
will fit into a baby or midsized tower with ample room for expansion;
|
||
and the whole thing will fit under a desk and make less noise than a
|
||
classic tower.</P
|
||
><P
|
||
>For users with really heavy expandability requirements,
|
||
rackmount PC cases do exist (ask prospective vendors). Typically a
|
||
rackmount case will have pretty much the same functionality as an
|
||
ordinary PC case. But, you can then buy drive racks (complete with
|
||
power supply), etc. to expand into. Also, you can buy passive
|
||
backplanes with up to 20 or so slots. You can either put a CPU card in
|
||
one of the slots, or connect it to an ordinary motherboard through one
|
||
of the slots.</P
|
||
><P
|
||
>Since USB has taken over most forms of detachable peripheral, a good
|
||
feature to look for in a case is USB ports mounted at the top forward edge
|
||
where it's easy to plug in digital cameras and the like.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="power"
|
||
></A
|
||
>3.5. Power Supplies and Fans</H2
|
||
><P
|
||
>A lot of people treat power supplies as a commodity, so many
|
||
interchangeable silver bricks. We know better — cheap power supplies
|
||
go bad, and when they go bad they have a nasty habit of taking out the
|
||
delicate electronics they're feeding. Also, the power supply tends to be
|
||
the noisiest component in your system.</P
|
||
><P
|
||
>Give preference to supplies with a Underwriter's Laboratories rating.
|
||
There's some controversy over optimum wattage level. On the one hand, you
|
||
want enough wattage for expansion. On the other, big supplies are noisier,
|
||
and if you draw too little current for the rating the delivered voltage can
|
||
become unstable. And the expected wattage load from peripherals is
|
||
dropping steadily. On the other hand, processors and their cooling fans
|
||
eat a lot more power than they used to.</P
|
||
><P
|
||
>The choice is generally between 200W and 300W. After some years of
|
||
deprecating 300W-and-up supplies as overkill, I'm now persuaded it's time
|
||
to go back to them; a modern processor can consume 50-75W by itself, and
|
||
for the newer dual-processor board the power supply needs to be rated 450W
|
||
or up.</P
|
||
><P
|
||
>Processors on modern motherboards run hot enough that all vendors
|
||
have gone to embedded temperature sensors and variable-speed
|
||
thermostat-controlled fans, out sheer self-defense (this used to be
|
||
a high-end only feature).</P
|
||
><P
|
||
>To cut noise, look for 120mm fans rather than the old-style 80mm
|
||
muffin fans. These can move the same amount of air per minute rotating at a
|
||
lower tip speed, which means less vortex formation and less noise. These
|
||
are now becoming standard even on cheap white-box hardware.</P
|
||
><P
|
||
>In garden-variety tower cases there often isn't enough airflow to
|
||
cool all components effectively with a single fan, even going at full
|
||
speed. And the single fan in the power supply was basically designed to
|
||
cool the power supply, not the components in the case. This is why
|
||
processors and some graphics cards have their own fans now.</P
|
||
><P
|
||
>A few years ago PCs often had two or more case fans in addition to
|
||
the power-supply fan. This made sense in the era of 80mm fans and lots of
|
||
expansion cards obstructing the airflow, but it was noisy. Nowadays, with
|
||
sound and graphics and Ethernet integrated onto motherboards, expansion
|
||
cards are much less common (and processors carry their own mini-fans).
|
||
Thus, today's standard is to mount one 120mm fan, usually low and forward
|
||
just beneath the disk-drive stack. This is much quieter, like by a factor
|
||
of three or four.</P
|
||
><P
|
||
>The noise produced by a fan is not just a function of the speed with
|
||
which it turns. It also depends on the nature of the airflow produced by
|
||
the fan blades and the bearings of the rotor. If the blades cause lots of
|
||
turbulent airflow, the fan produces lots of noise. One brand of fans that
|
||
is much more silent than most others even if going at full throttle is
|
||
<A
|
||
HREF="http://www.papstplc.com/"
|
||
TARGET="_top"
|
||
>Papst</A
|
||
>.
|
||
</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="motherboards"
|
||
></A
|
||
>3.6. Motherboards</H2
|
||
><P
|
||
>Provided you exercise a little prudence and stay out of the price
|
||
basement, motherboards and BIOS chips don't vary much in quality. There
|
||
are only six or so major brands of motherboard inside all those cases and
|
||
they're pretty much interchangeable; brand premiums are low to nonexistent
|
||
and cost is strictly tied to maximum speed and bus type. There are only
|
||
four major brands of BIOS chip (AMI, Phoenix, Mylex, Award) and not much to
|
||
choose between 'em but the look of the self-test screens (even the
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"name"</SPAN
|
||
> vendors use lightly customized versions of these). One
|
||
advantage Unix buyers have is that Unixes are built not to rely on the BIOS
|
||
code (because it can't be used in protected mode without more pain than
|
||
than it's worth). If your BIOS will boot properly, you're usually going to
|
||
be OK.</P
|
||
><P
|
||
>Some good features to look for in a motherboard include:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>Gold-plated contacts in the expansion slots and RAM
|
||
sockets. Base-metal contacts tend to grow an oxidation layer which
|
||
can cause intermittent connection faults that look like bad RAM chips
|
||
or boards. (This is why, if your hardware starts flaking out, one of
|
||
the first things to do is jiggle or remove the boards and reseat them,
|
||
and press down on the RAM chips to reseat them as well —this may
|
||
break up the oxidation layer. If this doesn't work, rubbing what
|
||
contacts you can reach with a soft eraser is a good fast way to remove
|
||
the oxidation film. Beware, some hard erasers, including many pencil
|
||
erasers, can strip off the plating, too!)</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>The board should be speed-rated as high as your
|
||
processor, of course. It's good if it's rated higher, so upgrade to a
|
||
faster processor is just a matter of dropping in the chip and a new
|
||
crystal.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>(I used to have "Voltage, temperature and fan speed monitoring
|
||
hardware." on this list. But processors run so hot nowadays that all
|
||
current motherboards have it.)</P
|
||
><P
|
||
>The dominant form factor is still ATX. Intel tried to replace it
|
||
with a new standard called BTX in late 2004-2005, but failed; the proposal
|
||
was effectively withdrawn in 2006. In January 2007 AMD announced a <A
|
||
HREF="http://www.dtxpc.org/"
|
||
TARGET="_top"
|
||
>DTX</A
|
||
> specification for small-form-factor
|
||
PCs; it seems also to have sunk without trace.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="AEN238"
|
||
></A
|
||
>3.7. Monitor and Video</H2
|
||
><P
|
||
>The largest user-visible change since the last major update of this
|
||
guide is that the CRT (cathode-ray tube) is dead. The manufacturers shut
|
||
down their production lines in late 2004; the remaining CRTs out there are
|
||
old stock that's been sitting in warehouses. The only reason to buy one
|
||
since then has been to get high-end resolution at a price lower than the
|
||
insanely expensive high-end flatscreens; with 1920x1440 flatscreens having
|
||
become generally available at reasonable prices even that
|
||
reason is gone. It's all flatscreens now, baby.</P
|
||
><P
|
||
>On flatscreens, only two statistics matter; pixel size and response
|
||
time. The biggest functional drawback of flatscreens relative to CRTs is
|
||
that they refresh more slowly, because cheical reactions in a flatscreen
|
||
pixel take longer than remodulating a flying electron beam. You'll never
|
||
notice this during ordinary desktop use, but it can cause streakiness and
|
||
artifacts when you're playing games or viewing movies. If you're going to
|
||
do that a lot, the price premium for a flatscreen with better response time
|
||
may be worth it.</P
|
||
><P
|
||
>Next, buy your card (if you have to; see next paragraph). This used
|
||
to be complicated, with issues like matching the video bandwidths of the
|
||
card and the CRT, and the amount of display memory. Now (unless you are a
|
||
gamer or have similarly extreme 3D acceleration requirements) it's simple;
|
||
all cards have enough display memory for every resolution in use, and the
|
||
issues are software (does it have an open-source driver, and do you
|
||
care?)</P
|
||
><P
|
||
>It's actually fairly likely you'll never buy a video card again.
|
||
Very capable graphics chips are routinely integrated onto motherboards now;
|
||
unless you're a gamer or somebody else who absolutely must have the latest
|
||
wheeze in 3D acceleration, they'll be good enough. Even this is not
|
||
a stable situation, as 3D acceleration is commoditizing too.</P
|
||
><P
|
||
>I used to carry a lot of material on different video standards,
|
||
interlacing, and flicker. That stuff is all obsolete now.</P
|
||
><P
|
||
>Here's what to look for on the monitor spec sheet:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>Screen size and format. Usually measured in
|
||
diagonal inches. Most displays are now in a <SPAN
|
||
CLASS="QUOTE"
|
||
>"widescreen"</SPAN
|
||
>
|
||
format (16:10 ratio of width:height) rather than the older 5:4 or 4:3
|
||
ratios common for CRTs and older flat panel screens. A <SPAN
|
||
CLASS="QUOTE"
|
||
>"19
|
||
inch"</SPAN
|
||
> widescreen monitor generally has considerably fewer pixels
|
||
than a <SPAN
|
||
CLASS="QUOTE"
|
||
>"19 inch"</SPAN
|
||
> 5:4 ratio one. Unfortunately, this chane is
|
||
bad for pogrammers, as it tends to lose us the vertical pixel resolution we
|
||
want for editor windows.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Screen resolution. 1280x1024 is now low end on the
|
||
desktop. Seventeen inch 1280x1024 screens are the bargain basement now,
|
||
many manufacturers have already switched production to 19 inch widescreen
|
||
1440x900 screens instead. The cost difference between such screens and 20
|
||
inch 1680x1050 screens is very small, making the 20 inch screens a better
|
||
choice unless funds (or desktop space!) are very tight.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>5ms or lower response time. 3ms is better. There is some
|
||
marketing-speak going on in the way the response time is specified (grey to
|
||
gray rather than black to white) but since most manufacturers do it this
|
||
way these times are usually comparable between different manufacturers
|
||
screens.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Does it have a tilt-and-swivel base? Adequate
|
||
controls, including both horizontal and vertical size and horizontal
|
||
and vertical centering? A color-temperature control is a plus; the last is
|
||
particularly important if you compose graphics on screen for hardcopy
|
||
from a printer.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>If you can, buy your monitor from someplace that will let you
|
||
see the same monitor (the very unit you will walk out the door with,
|
||
not a different or `demo' unit of the same model) that will be on your
|
||
system. There's significant quality variation (even in "premium" monitor
|
||
brands) even among monitors of the same make and model.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="dvd"
|
||
></A
|
||
>3.8. DVD Drives</H2
|
||
><P
|
||
>DVD drives have two main uses in computer systems: playback of video
|
||
DVDs, and use for data storage (either installation media or backups, or
|
||
even as a primary drive in a few specialized systems).</P
|
||
><P
|
||
>DVD video playback used to be problematic on Unix due to various
|
||
stupid copy-protection schemes in firmware, but they have long since
|
||
been cracked. These days, any SATA DVD will do fine.</P
|
||
><P
|
||
>DVD burners (drives that can read and write CDROM media as well as
|
||
several kinds of DVD media) are now low cost and useful. The SATA interface
|
||
has taken over here, too. Linux and most current PC Unix-like systems will
|
||
work fine with either interface, which is good as most PCs now ship with
|
||
one.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="sound"
|
||
></A
|
||
>3.9. Sound Cards and Speakers</H2
|
||
><P
|
||
>You can't buy a really bad sound card any more. Even low-end
|
||
sound cards or the sound chips embedded in a lot of PC motherboards
|
||
these days support support all these features:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>16-bit sampling (for 65536 dynamic levels rather
|
||
than 256).</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Mono and stereo support.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Full-duplex mode.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Sampling rate of 44.1KHz (CD-quality).</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>MIDI interface via a standard 15-pin D-shell
|
||
connector.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>RCA output jacks for headphones or speakers.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>A microphone jack for sound input.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>If you are interested in multi-track digital recording, two
|
||
particularly good choices are the M-Audio Delta, or RME Hammerfall series
|
||
of cards. Decent (and lower cost!) two-channel cards for more normal use
|
||
are those using the ICE1712 (Envy24) and ICE1724 (Envy24HT) audio chips.
|
||
For normal users, though, the on-motherboard chips will work fine.</P
|
||
><P
|
||
>A rather comprehensive list of sound cards and chips supported by the
|
||
ALSA project, which is the main way sound cards are supported under Linux,
|
||
can be found at <A
|
||
HREF="http://www.alsa-project.org/main/index.php/Matrix:Main"
|
||
TARGET="_top"
|
||
>ALSA Sound
|
||
Card Matrix</A
|
||
>.</P
|
||
><P
|
||
>In speakers, look for a magnetically-shielded enclosure with volume,
|
||
bass and treble controls. Some speakers run off the card's 4-watt signal;
|
||
others are <SPAN
|
||
CLASS="QUOTE"
|
||
>"self-powered"</SPAN
|
||
>, using batteries or a separate power
|
||
supply. Your major buying choice is which one of these options to pursue.
|
||
Usually you'll want separately-powered speakers. If appropriate for your
|
||
listening habits, a pair of decent headphones will get you better quality
|
||
sound for the money compared to speakers.</P
|
||
><P
|
||
>One final, important tip: that audio cable from your CD-ROM back to
|
||
the sound card is used only when you play audio CD-ROMs through your
|
||
speakers. Software-generated sound goes through the system bus, so you can
|
||
play games with sound even if your sound board or motherboard won't accept
|
||
the audio cable connector.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="modems"
|
||
></A
|
||
>3.10. Modems</H2
|
||
><P
|
||
>Demand for (dialup telephone) modems is dropping as more and more
|
||
people get broadband Internet through DSL and cable. This section still
|
||
has as much detail as it does only because (a) there are people out beyond
|
||
the exurbs who can't get broadband, and (b) there are one or two remaining
|
||
traps for the unwary.</P
|
||
><P
|
||
>The modem market has stabilized and standardized. If you can spend
|
||
$59, get a U.S. Robotics V.92 USB external. You can then know that you've
|
||
got the best and skip the rest of this section. If you really must
|
||
economize, spend $39 for the internal-card version (but you'll probably
|
||
regret the $20 first time you have to do diagnostics).</P
|
||
><DIV
|
||
CLASS="note"
|
||
><P
|
||
></P
|
||
><TABLE
|
||
CLASS="note"
|
||
WIDTH="100%"
|
||
BORDER="0"
|
||
><TR
|
||
><TD
|
||
WIDTH="25"
|
||
ALIGN="CENTER"
|
||
VALIGN="TOP"
|
||
><IMG
|
||
SRC="../images/note.gif"
|
||
HSPACE="5"
|
||
ALT="Note"></TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
VALIGN="TOP"
|
||
><P
|
||
>If you live somewhere with <EM
|
||
>really</EM
|
||
> bad
|
||
telephone lines, the U.S. Robotics V.92 Business Modem may be truly "the
|
||
best" for your needs, though it is about four times the price of the
|
||
U.S. Robotics V.92 USB external, which is marketed for home use. See the
|
||
<A
|
||
HREF="http://www.usrobotics.com"
|
||
TARGET="_top"
|
||
>U.S. Robotics</A
|
||
> web site for
|
||
current product numbers and more detailed specifications.</P
|
||
></TD
|
||
></TR
|
||
></TABLE
|
||
></DIV
|
||
><P
|
||
>The modem market is like consumer electronics (and unlike the
|
||
computer market as a whole) in that price is a very poor predictor of
|
||
performance. For ordinary file transfers, some $50 modems are better than
|
||
some $150 modems. Paying top dollar mainly buys you better tolerance of
|
||
poor connections and better performance at heavy-duty bi-directional
|
||
transfers (such as you would generate, for exmaple, using SLIP or PPP over
|
||
a leased line to an Internet provider).</P
|
||
><P
|
||
>In today's market all modems do a nominal 56kbps —V.90 and V.92
|
||
plus V.29 or V.17 fax transmission and reception (over plain old phone
|
||
lines you won't get more than 53K of that). You don't see much in the way
|
||
of slow/cheap to fast/expensive product ranges within a single brand,
|
||
because competition is fierce and for many modem board designs (those
|
||
featuring DSP (Digital Signal Processor) chips run by a program in ROM)
|
||
adding a new protocol is basically a software change.</P
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="modem_format"
|
||
></A
|
||
>3.10.1. Internal vs. External</H3
|
||
><P
|
||
>Most modems come in two packagings: internal, designed to fit in a PC
|
||
card slot, and external, with its own case, power supply, and front-panel
|
||
lights. Typically you'll pay $20 to $30 more for an external modem than
|
||
you will for the internal equivalent. You'll also need a serial or USB
|
||
port to connect your external modem to.</P
|
||
><P
|
||
>Pay that premium — being able to see the blinkenlights on
|
||
the external ones will help you understand and recover from
|
||
pathological situations. For example, if your Unix system is prone to
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"screaming-tty"</SPAN
|
||
> syndrome, you'll quickly learn to recognize the
|
||
pattern of flickers that goes with it. Punch the hangup/reset button
|
||
on an external modem and you're done — whereas with an internal
|
||
modem, you have to go root and flounder around killing processes and
|
||
maybe cold-boot the machine just to reset the card.</P
|
||
><P
|
||
>See <A
|
||
HREF="http://linuxmafia.com/~rick/faq/"
|
||
TARGET="_top"
|
||
>Rick's
|
||
Rants</A
|
||
> for extended discussion of this point.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="modem_pitfalls"
|
||
></A
|
||
>3.10.2. Pitfalls to Avoid</H3
|
||
><P
|
||
>Don't buy a serial (RS232C) modem. This used to be the only kind
|
||
there was, but they were always a bitch to configure and troubleshoot.
|
||
Go USB instead; the sanity you save may be your own.</P
|
||
><P
|
||
>If the abbreviation <SPAN
|
||
CLASS="QUOTE"
|
||
>"RPI"</SPAN
|
||
> occurs anywhere on the box,
|
||
don't even consider buying the modem. RPI (Rockwell Protocol Interface) is
|
||
a proprietary <SPAN
|
||
CLASS="QUOTE"
|
||
>"standard"</SPAN
|
||
> that allows modem makers to save a
|
||
few bucks at your expense by using a cheap-jack Rockwell chipset that
|
||
doesn't do error correction. Instead, it hands the job off to a modem
|
||
driver which (on a Unix machine) you will not have.</P
|
||
><P
|
||
>Also avoid anything called a <SPAN
|
||
CLASS="QUOTE"
|
||
>"Windows Modem"</SPAN
|
||
> or
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"WinModem"</SPAN
|
||
>, <SPAN
|
||
CLASS="QUOTE"
|
||
>"HCF"</SPAN
|
||
>, or <SPAN
|
||
CLASS="QUOTE"
|
||
>"HSP"</SPAN
|
||
>; these
|
||
lobotomized pieces of crap require a Windows DLL to run. They will eat up
|
||
to 25% of your processor clocks during transfers, and hog high-priority
|
||
interrupts (causing your machine to stall under Windows even if your
|
||
processor still has spare cycles). </P
|
||
><P
|
||
>A good way to avoid falling into the WinModem trap is to look for
|
||
the designation "OEM modem". This is apparently the new industry-speak
|
||
for a modem with an on-board harware DSP. Occasionally you'll see these
|
||
called "gaming modems".</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="AEN317"
|
||
></A
|
||
>3.10.3. Fax Modems</H3
|
||
><P
|
||
>Many modems come with bundled Windows fax software that is at best
|
||
useless under Unix, and at worst a software kluge to cover inadequate
|
||
hardware. Avoid these bundles and buy a bare modem — it's cheaper,
|
||
and lowers the likelihood that something vital to your communications needs
|
||
has been left out of the hardware.</P
|
||
><P
|
||
>Avoid <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class 1"</SPAN
|
||
> and <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class 2"</SPAN
|
||
> modems. Look
|
||
for <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class 2.0"</SPAN
|
||
> for the full EIA-standard command set.</P
|
||
><P
|
||
>Fax capability is included with effectively all modems these days; it's
|
||
cheap for manufacturers, being basically a pure software add-on. The
|
||
CCITT also sets fax protocol standards. Terms to know:</P
|
||
><P
|
||
></P
|
||
><DIV
|
||
CLASS="variablelist"
|
||
><DL
|
||
><DT
|
||
>V.29</DT
|
||
><DD
|
||
><P
|
||
> CCITT standard for Group III fax encoding at 9600bps</P
|
||
></DD
|
||
><DT
|
||
>V.17</DT
|
||
><DD
|
||
><P
|
||
> CCITT standard for Group III fax encoding at
|
||
14400bps</P
|
||
></DD
|
||
></DL
|
||
></DIV
|
||
><P
|
||
>There's a separate series of standards for software control of fax
|
||
modems over the serial (or USB) line maintained by the Electronics Industry
|
||
Association and friends. These are:</P
|
||
><P
|
||
><I
|
||
CLASS="firstterm"
|
||
>Class 1</I
|
||
> — base EIA standard for fax
|
||
control as extensions to the Hayes AT command set.</P
|
||
><P
|
||
><I
|
||
CLASS="firstterm"
|
||
>Class 2.0</I
|
||
> — enhanced EIA standard
|
||
including compression, error correction, station ID and other
|
||
features.</P
|
||
><P
|
||
><I
|
||
CLASS="firstterm"
|
||
>Class 2</I
|
||
> — marketroidian for anything
|
||
between Class 1 and Class 2.0. Different <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class 2"</SPAN
|
||
> modems
|
||
implement different draft subsets of the 2.0 standard, so <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class
|
||
2"</SPAN
|
||
> fax software won't necessarily drive any given <SPAN
|
||
CLASS="QUOTE"
|
||
>"Class
|
||
2"</SPAN
|
||
> modem.</P
|
||
><P
|
||
>There's also a proprietary Intel "standard" called CAS, Communicating
|
||
Applications Specification. Ignore it; only Intel products support it.</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="printers"
|
||
></A
|
||
>3.11. Printers</H2
|
||
><P
|
||
>The most important thing to optimize nowadays is cost of consumables.
|
||
Printer manufacturers, especially at the low end, have adopted a model
|
||
under which they sell printers with near-zero or even negative margin, then
|
||
gouge you horribly on the cost of cartridges and ink. Common tactics
|
||
include (a) shipping half-filled "starter" cartridges with your printer, so
|
||
you have to replace much sooner than you'd think, (b) toner-empty
|
||
sensors deliberately miscalibrated to blink the error light on your printer
|
||
when they're still a quarter to a third full, and (c) electronic
|
||
countermeasures to lock out cheap third-party refills - in one notorious
|
||
case, a printer manufacturer used the DMCA to sue refill vebdoers who
|
||
circumvented these!</P
|
||
><P
|
||
>Better dealers (the Staples chain, for example) will show you
|
||
a chart covering price and consumable-cost-per-page for all the models
|
||
they carry. If you don't see this, leave. When you do, estimate your
|
||
monthly print volume and trade off up-front against consumables price.
|
||
appropriately. Hint: The vendors count on you underestimating your volume
|
||
and consumables cost, and you usually will. Payiing a few extra bucks
|
||
up front to lower that cost is smart.</P
|
||
><P
|
||
>Other than that, there really isn't all that much to be said about
|
||
printers; the market is thoroughly commoditized and printer capabilities
|
||
pretty much independent of the rest of your hardware. The PC-clone
|
||
magazines will tell you what you need to know about print quality, speed,
|
||
features, etc. The business users they feed on are obsessed with all these
|
||
things.</P
|
||
><P
|
||
>(There used to be a problem with <SPAN
|
||
CLASS="QUOTE"
|
||
>"GDI printers"</SPAN
|
||
> and
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"WinPrinters"</SPAN
|
||
> that only worked with Windows —they
|
||
required special drivers that took over your CPU to do image processing,
|
||
These were such a bad idea that they have basically disappeared off the
|
||
market.)</P
|
||
><P
|
||
>Most popular printers are supported by GhostScript, and so it's easy
|
||
to make them do PostScript. If you're buying any letter-quality
|
||
printer (laser or ink-jet), check to see if it's on GhostScript's
|
||
supported device list — otherwise you'll have to pay a premium for
|
||
Postscript capability! Postscript is still high-end in the Windows
|
||
market, but it's ubiquitous in the Unix world.</P
|
||
><P
|
||
>Warning, however: if you're using ghostscript on a non-Postscript
|
||
printer, printspeed will be slow, especially with a serial printer. A
|
||
bitmapped 600 dpi page has a <EM
|
||
>lot</EM
|
||
> of pixels on it. At
|
||
today's prices, paying the small premium for Postscript capability makes
|
||
sense.</P
|
||
><P
|
||
>If you're buying a printer for home, an inkjet is a good choice
|
||
because it doesn't use gobs of power and you won't have the
|
||
toner/ozone/noise/etc mess that you do with a laser. If all
|
||
you want is plain-ASCII, dot-matrix is cheaper to buy and run — if
|
||
you can find one. Inexpensive ink-jets and lasers have almost driven
|
||
them off the market.</P
|
||
><P
|
||
>Inkjets are great in that they're cheap, many of them do color, and
|
||
there are many kinds which aren't PCL but are understood by
|
||
Ghostscript anyway. If you print very infrequently (less than weekly,
|
||
say), you should be careful to buy a printer whose print head gets
|
||
replaced with every ink cartrige: infrequent use can lead to the
|
||
drying of the ink, both in the ink cartrige and in the print head.
|
||
The print heads you don't replace with the cartrige tend to cost
|
||
nearly as much as the printer (~$200 for an Epson Stylus 800) once the
|
||
warranty runs out (the third such repair, just after the warranty
|
||
expired, totalled one informant's Stylus 800). Be careful, check
|
||
print head replacement costs ahead of time, and run at least a
|
||
cleaning cycle if you don't actually print anything in a given week.
|
||
(Conversely, toner starts out dry, and ribbon ink won't evaporate for
|
||
years...if you truly print only rarely, but neither a dot matrix nor a
|
||
laser makes sense, consider buying no printer and taking your
|
||
PostScript files to a copy shop...)</P
|
||
><P
|
||
>Nowadays, a lot of printers are moving away from parallel-port
|
||
interfaces to USB. This is a good idea, because USB devices announce
|
||
themselves to the host computer and can be automatically configured.
|
||
Parallel ports (and serial ports for that matter) are becoming obsolete.
|
||
Many new PC motherboards no longer include them.</P
|
||
><P
|
||
>Many printers (even some sub-$100 models) now come with a network
|
||
(10/100 Ethernet) interface. This make sharing them trivial, and also
|
||
avoids having to leave a desktop PC powered on so others (using notebooks
|
||
perhaps) can print to your printer. Therefore, such printers are worth
|
||
considering in many networked environments, including home networks.</P
|
||
><P
|
||
>In the near future, new motherboards may stop including parallel and
|
||
serial ports altogether. That's another good reason to go with a USB-
|
||
or Ethernet-capable printer.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="power_protection"
|
||
></A
|
||
>3.12. Power Protection</H2
|
||
><P
|
||
>I strongly recommend that you buy a UPS to protect your hardware and
|
||
data. MOV-filtered power bars make nice fuses (they're cheap to replace),
|
||
but they're not enough. I have written a <A
|
||
HREF="http://www.tldp.org/HOWTO/UPS-HOWTO"
|
||
TARGET="_top"
|
||
>UPS
|
||
HOWTO</A
|
||
> that provides more complete coverage of what used to be in
|
||
this section.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="rfi"
|
||
></A
|
||
>3.13. Radio Frequency Interference</H2
|
||
><P
|
||
>(Thanks to Robert Corbett <Robert.Corbett@Eng.Sun.COM> for
|
||
contributing much of this section)</P
|
||
><P
|
||
>Radio Frequency Interference (RFI) is a growing problem with PC-class
|
||
machines. Today's processor speeds are such that the electromagnetic noise
|
||
generated by a PC's circuitry in normal operation can degrade or jam radio
|
||
and TV reception in the neighborhood. Such noise is called Radio Frequency
|
||
Interference (RFI). Computers, as transmitting devices, are regulated by
|
||
the Federal Communications Commission (FCC).</P
|
||
><P
|
||
>FCC regulations recognize two classes of computer:</P
|
||
><P
|
||
>If a PC is to be used in a home or apartment, it must be
|
||
certified to be FCC class B. If it is not, neighbors have a legal
|
||
right to prevent its use. FCC class A equipment is allowed in
|
||
industrial environments.</P
|
||
><P
|
||
>Many systems are not FCC class B. Some manufacturers build
|
||
boxes that are class B and then ship them with class A monitors or
|
||
external disk drives. Even the cables can be a source of RFI.</P
|
||
><P
|
||
>It pays to be cautious. For example, the Mag MX17F is FCC class B.
|
||
There are less expensive versions of the MX17 that are not. The Mag MX17
|
||
is a great monitor. It would be painful to own one and not be allowed to
|
||
use it.</P
|
||
><P
|
||
>An upgradeable system poses special problems. A system that is
|
||
FCC class B with a 33 MHz CPU might not be when the CPU is upgraded to
|
||
a 50 or 66 MHz CPU. Some upgrades require knockouts in the case to be
|
||
removed. If a knockout is larger than whatever replaces it, RFI can
|
||
leak out through the gap. Grounded metal shims can eliminate the
|
||
leaks.</P
|
||
><P
|
||
>Even Class B systems don't mix well with wireless phonesets (not cellular
|
||
phones, but the kind with a base station and antennaed headset). You'll often
|
||
find a wireless phone hard to use withing 20 feet of a Class B machine.</P
|
||
><P
|
||
>To cut down on RFI, get a good metal case with tight joints, or at
|
||
least make sure any plastic one you buy has a conductive lining. You
|
||
can also strip the painted metal-to-metal contacting parts of paint so
|
||
that there's good conductive metal contact. Paint's a poor conductor
|
||
in most cases, so you can get some benefit from this.</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="optimize"
|
||
></A
|
||
>4. What To Optimize</H1
|
||
><DIV
|
||
CLASS="sect2"
|
||
><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="AEN378"
|
||
></A
|
||
>4.1. First, add more memory</H2
|
||
><P
|
||
>Max out your memory. Having lots of free memory will improve your
|
||
virtual-memory performance (and Unix takes advantage of extra memory more
|
||
effectively than Windows does). Fortunately, with RAM as cheap as it is
|
||
now, a gigabyte or three is unlikely to bust your budget even if you're
|
||
economizing.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="AEN381"
|
||
></A
|
||
>4.2. Bus and Disk speeds</H2
|
||
><P
|
||
>Most people think of the processor as the most important choice in
|
||
specifying any kind of personal-computer system. But for typical job loads
|
||
under Linux, the processor type is nearly a red herring — it's far
|
||
more important to specify a capable system bus and disk I/O subsystem. If
|
||
you don't believe this, you may find it enlightening to keep
|
||
<SPAN
|
||
CLASS="citerefentry"
|
||
><SPAN
|
||
CLASS="refentrytitle"
|
||
>top</SPAN
|
||
>(1)</SPAN
|
||
>
|
||
running for a while as you use your machine. Notice how seldom the CPU
|
||
idle percentage drops below 90%!</P
|
||
><P
|
||
>It's true that after people upgrade their motherboards they often do
|
||
report a throughput increase. But this is often more due to other changes
|
||
that go with the processor upgrade, such as improved cache memory or an
|
||
increase in the clocking speed of the system's front-side bus (enabling
|
||
data to get in and out of the processor faster).</P
|
||
><P
|
||
>If you're buying for Linux on a fixed budget, it makes sense to trade
|
||
away some excess processor clocks to get a faster bus and disk subsystem.
|
||
If you're building a monster hot-rod, go ahead and buy that fastest
|
||
available processor — but once you've gotten past that gearhead
|
||
desire for big numbers, pay careful attention to bus speeds and your disk
|
||
subsystem, because that's where you'll get the serious performance wins.
|
||
The gap between processor speed and I/O subsystem throughput has only
|
||
widened in the last five years.</P
|
||
><P
|
||
>How does it translate into a recipe in 2010? Like this; if
|
||
you're building a hot rod,</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
><EM
|
||
>Do</EM
|
||
> buy a machine with the fastest
|
||
available "front-side" (e.g. processor-to-memory) bus.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
><EM
|
||
>Do</EM
|
||
> get the fastest SATA disks you can
|
||
get your hands on.</P
|
||
></LI
|
||
></UL
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="diskwars"
|
||
></A
|
||
>4.3. Optimizing your disk subsystem</H2
|
||
><P
|
||
>For the fastest disks you can find, pay close attention to
|
||
average seek and latency time. The former is an average time
|
||
required to seek to any track; the latter is the maximum time
|
||
required for any sector on a track to come under the heads, and is
|
||
a function of the disk's rotation speed.</P
|
||
><P
|
||
>Of these, average seek time is <EM
|
||
>much</EM
|
||
> more
|
||
important. When you're running Linux or any other virtual-memory operating
|
||
system, a one millisecond faster seek time can make a really substantial
|
||
difference in system throughput. Back when PC processors were slow enough
|
||
for the comparison to be possible (and I was running System V Unix), it was
|
||
easily worth as much as a 30MHz increment in processor speed. Today the
|
||
corresponding figure would probably be as much as 300MHz!</P
|
||
><P
|
||
>The manufacturers themselves avoid running up seek time on the
|
||
larger-capacity drives by stacking platters vertically rather than
|
||
increasing the platter size. Thus, seek time (which is proportional
|
||
to the platter radius and head-motion speed) tends to be constant across
|
||
different capacities in the same product line. This is good because it
|
||
means you don't have to worry about a capacity-vs.-speed tradeoff.</P
|
||
><P
|
||
>Average drive latency is inversely proportional to the disk's
|
||
rotational speed. For years, most disks spun at 3600 rpm; most disks now
|
||
spin at 7,200 or 10,000rpm, and high-end disks at 15,000 rpm. These
|
||
fast-spin disks run extremely hot; cooling is becoming a critical
|
||
constraint in drive design.</P
|
||
><P
|
||
>For years, your basic decision was SATA vs. SCSI (the older IDE and
|
||
EIDE buses are long obsolete). Not in 2009; SATA 3 devices and controllers
|
||
are good enough that the performance advantage of SCSI is marginal unless
|
||
you are designing a super-high-end server box - slightly faster transfer
|
||
speeds (320MB/s vs. 300MB/s) and slightly better susrained throughput.</P
|
||
><P
|
||
>The SCSI price premium entailed in an extra controller and more
|
||
expensive disks are no longer worth it for the home builder, even from the
|
||
point of view of grizzled old SCSI partisans like me. Accordingly, I've
|
||
dropped most of the detailed SCSI information I used to carry here.</P
|
||
><P
|
||
>Final note: Solid-state drives loom on the horizon as replacements
|
||
for SATA disks, but the price per megabyte is still high enough that as
|
||
yet they're only being deployed in small capacities on netbooks. Watch
|
||
this space.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="iotune"
|
||
></A
|
||
>4.4. Tuning Your I/O Subsystem</H2
|
||
><P
|
||
><EM
|
||
>(This section comes to us courtesy of Perry The Cynic,
|
||
<perry@sutr.cynic.org>; it was written in 1998. My own experience
|
||
agrees pretty completely with his. I have revised the numbers in it since
|
||
to reflect more recent developments.)</EM
|
||
></P
|
||
><P
|
||
>Building a good I/O subsystem boils down to two major points:
|
||
<EM
|
||
>pick matched components</EM
|
||
> so you don't over-build any
|
||
piece without benefit, and <EM
|
||
>construct the whole pipe such that
|
||
it can feed what your OS/application combo needs</EM
|
||
>.</P
|
||
><P
|
||
>It's important to recognize that <SPAN
|
||
CLASS="QUOTE"
|
||
>"balance"</SPAN
|
||
> is with
|
||
respect to not only a particular processor/memory subsystem, but also to a
|
||
particular OS and application mix. A Unix server machine running the whole
|
||
TCP/IP server suite has radically different I/O requirements than a
|
||
video-editing workstation. For the <SPAN
|
||
CLASS="QUOTE"
|
||
>"big boys"</SPAN
|
||
> a good
|
||
consultant will sample the I/O mix (by reading existing system performance
|
||
logs or taking new measurements) and figure out how big the I/O system
|
||
needs to be to satisfy that app mix. This is not something your typical
|
||
Linux buyer will want to do; for one, the application mix is not static and
|
||
will change over time. So what you'll do instead is design an I/O subsystem
|
||
that is internally matched and provides maximum potential I/O performance
|
||
for the money you're willing to spend. Then you look at the price points
|
||
and compare them with those for the memory subsystem. That's the most
|
||
important trade-off inside the box.</P
|
||
><P
|
||
>So the job now is to design and buy an I/O subsystem that is well
|
||
matched to provide the best bang for your buck. The two major performance
|
||
numbers for disk I/O are latency and bandwidth. Latency is how long a
|
||
program has to wait to get a little piece of random data it asked for.
|
||
Bandwidth is how much contiguous data can be sent to/from the disk once
|
||
you've done the first piece. Latency is measured in milliseconds (ms);
|
||
bandwidth in megabytes per second (MB/s). Obviously, a third number of
|
||
interest is how big all of your disks are together (how much storage you've
|
||
got), in Gigabytes (GB).</P
|
||
><P
|
||
>Within a rather big envelope, minimizing latency is the cat's meow.
|
||
Every millisecond you shave off effective latency will make your system
|
||
feel significantly faster. Bandwidth, on the other hand, only helps you
|
||
if you suck a big chunk of contiguous data off the disk, which happens
|
||
rarely to most programs. You have to keep bandwidth in mind to avoid
|
||
mis-matching pieces, because (obviously) the lowest usable bandwidth in
|
||
a pipe constrains everything else.</P
|
||
><P
|
||
>I'm going to ignore IDE. IDE is no good for multi-processing systems,
|
||
period. You may use an IDE CD-ROM if you don't care about its
|
||
performance, but if you care about your I/O performance, go SCSI.
|
||
(Beware that if you mix an IDE CD-ROM with SCSI drives under Linux,
|
||
you'll have to run a SCSI emulation layer that is a bit flaky.)</P
|
||
><P
|
||
>Let's look at the disks first. Whenever you seriously look at a
|
||
disk, <EM
|
||
>get its data sheet</EM
|
||
>. Every reputable
|
||
manufacturer has them on their website; just read off the product code
|
||
and follow the bouncing lights. Beware of numbers (`<12ms fast!')
|
||
you may see in ads; these folks often look for the lowest/highest
|
||
numbers on the data sheet and stick them into the ad copy. Not
|
||
dishonest (usually), but ignorant.</P
|
||
><P
|
||
>What you need to find out for a disk is:</P
|
||
><P
|
||
></P
|
||
><OL
|
||
TYPE="1"
|
||
><LI
|
||
><P
|
||
>What kind of SCSI interface does it have? Look for
|
||
"fast", "ultra", and "wide". Ignore disks that say "fiber"
|
||
(this is a specialty physical layer not appropriate for the insides
|
||
of small computers). Note that you'll often find the same disk with
|
||
different interfaces.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>What is the "typical seek" time (ms)? Make sure
|
||
you get "typical", not "track-to-track" or "maximum" or some other
|
||
measure (these don't relate in obvious ways, due to things like
|
||
head-settling time).</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>What is the rotational speed? This is typically
|
||
4500, 5400, 7200, 10000, or 15000 rpm (rotations per minute). Also look
|
||
for "rotational latency" (in ms). (In a pinch, average rotational
|
||
latency is approx. 30000/rpm in milliseconds.)</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>What is the ‘media transfer rate’ or speed (in
|
||
MB/s)? Many disks will have a range of numbers (say,
|
||
7.2-10.8MB/s). Don't confuse this with the "interface transfer rate"
|
||
which is always a round number (10 or 20 or 40MB/s) and is the speed of
|
||
the SCSI bus itself.</P
|
||
></LI
|
||
></OL
|
||
><P
|
||
>These numbers will let you do apple-with-apples comparisons of disks.
|
||
Beware that they will differ on different-size models of the same disk;
|
||
typically, bigger disks have slower seek times.</P
|
||
><P
|
||
>Now what does it all mean? Bandwidth first: the `media transfer rate'
|
||
is how much data you can, under ideal conditions, get off the disk per
|
||
second. This is a function mostly of rotation speed; the faster the
|
||
disk rotates, the more data passes under the heads per time unit. This
|
||
constrains the sustained bandwidth of <EM
|
||
>this disk</EM
|
||
>.</P
|
||
><P
|
||
>More interestingly, your effective latency is the sum of typical seek
|
||
time and rotational latency. So for a disk with 8.5ms seek time and 4ms
|
||
rotational latency, you can expect to spend about 12.5ms between the
|
||
moment the disk `wants' to read your data and the moment when it
|
||
actually starts reading it. This is the one number you are trying to
|
||
make small. Thus, you're looking for a disk with low seek times and
|
||
high rotation (RPM) rates.</P
|
||
><P
|
||
>For comparison purposes, the first hard drive I ever bought was a
|
||
20MB drive with 65ms seek time and about 3000RPM rotation. A floppy drive
|
||
has about 100-200ms seek time. A CD-ROM drive can be anywhere between 120ms
|
||
(fast) and 400ms (slow). The best IDE harddrives have about 10-12ms and
|
||
5400 rpm. The best SCSI harddrive I know (the Fujitsu MAM) runs
|
||
3.9ms/15000rpm.</P
|
||
><P
|
||
>Fast, big drives are expensive. Really big drives are very
|
||
expensive. Really fast drives are pretty expensive. On the other end,
|
||
really slow, small drives are cheap but not cost effective, because it
|
||
doesn't cost any less to make the cases, ship the drives, and sell
|
||
them.</P
|
||
><P
|
||
>In between is a ‘sweet spot’ where moving in either
|
||
direction (cheaper or more expensive) will cost you more than you get out
|
||
of it. The sweet spot moves (towards better value) with time. If you
|
||
can make the effort, go to your local computer superstore and write down a
|
||
dozen or so drives they sell ‘naked’. (If they don't sell at
|
||
least a dozen hard drives naked, find yourself a better store. Use the Web,
|
||
Luke!) Plot cost against size, seek and rotational speed, and it will
|
||
usually become pretty obvious which ones to get for your budget.</P
|
||
><P
|
||
>Do look for specials in stores; many superstores buy overstock from
|
||
manufacturers. If this is near the sweet spot, it's often
|
||
surprisingly cheaper than comparable drives. Just make sure you
|
||
understand the warranty procedures.</P
|
||
><P
|
||
>Note that if you need a lot of capacity, you may be better off with
|
||
two (or more) drives than a single, bigger one. Not only can it be cheaper
|
||
but you end up with two separate head assemblies that move independently,
|
||
which can cut down on latency quite a bit (see below).</P
|
||
><P
|
||
>If you find yourself at the high end of the bandwidth game, be aware
|
||
that the theoretical maximum of the PCI bus itself is 132MB/s. That
|
||
means that a dual ultra/wide SCSI controller (2x40MB/s) can fill more
|
||
than half of the PCI bus's bandwidth, and it is not advised to add
|
||
another fast controller to that mix. As it is, your device driver
|
||
better be well written, or your entire system will melt down (figuratively
|
||
speaking).</P
|
||
><P
|
||
>Incidentally, all of the numbers I used are ‘optimal’
|
||
bandwidth numbers. The real scoop is usually somewhere between 50-70% of
|
||
nominal, but things tend to cancel out — the drives don't quite
|
||
transfer as fast as they might, but the SCSI bus has overhead too, as does
|
||
the controller card.</P
|
||
><P
|
||
>Whether you have a single disk or multiple ones, on one or several
|
||
SCSI buses, you should give careful thought to their partition layout.
|
||
Given a set of disks and controllers, this is the most crucial
|
||
performance decision you'll make.</P
|
||
><P
|
||
>A partition is a contiguous group of sectors on the disk. Partitioning
|
||
typically starts at the outside and proceeds inwards. All partitions
|
||
on one disk share a single head assembly. That means that if you try
|
||
to overlap I/O on the first and last partition of a disk, the heads
|
||
must move full stroke back and forth over the disk, which can
|
||
radically increase seek time delays. A partition that is in the
|
||
middle of a partition stack is likely to have best seek performance,
|
||
since at worst the heads only have to move half-way to get there (and
|
||
they're likely to be around the area anyway).</P
|
||
><P
|
||
>Whenever possible, split partitions that compete onto different
|
||
disks. For example, /usr and the swap should be on different disks if
|
||
at all possible (unless you have outrageous amounts of RAM).</P
|
||
><P
|
||
>Another wrinkle is that most modern disks use `zone sectoring'. The
|
||
upshot is that outside partitions will have higher bandwidth than inner
|
||
ones (there is more data under the heads per revolution). So if you
|
||
need a work area for data streaming (say, a CD-R pre-image to record),
|
||
it should go on an outside (early numbered) partition of a
|
||
fast-rotating disk. Conversely, it's a good convention to put
|
||
rarely-used, performance-uncritical partitions on the inside (last).</P
|
||
><P
|
||
>Ah yes, caches. There are three major points where you could cache
|
||
I/O buffers: the OS, the controller card or chip in your machine, and the
|
||
on-disk controller. Intelligent OS caching is by far the biggest win, for
|
||
many reasons. RAM caches on controller cards are pretty pointless these
|
||
days; you shouldn't pay extra for them, and experiment with disabling them
|
||
if you're into tinkering.</P
|
||
><P
|
||
>RAM caches on the drives themselves are a mixed bag. At moderate size
|
||
(1-2MB), they are a potential big win for Windows 95/98, because
|
||
Windows has stupid VM and I/O drivers. If you run a true multi-tasking
|
||
OS like Linux, having unified RAM caches on the disk is a significant
|
||
loss, since the overlapping I/O threads kick each other out of the
|
||
cache, and the disk ends up performing work for nothing.</P
|
||
><P
|
||
>Most high-performance disks can be reconfigured (using mode page
|
||
parameters, see above) to have `segmented' caches (sort of like a
|
||
set-associative memory cache). With that configured properly, the RAM
|
||
caches can be a moderate win, not because caching is so great on the
|
||
disk (it's much better in the OS), but because it allows the disk
|
||
controller more flexibility to reschedule its I/O request queue. You
|
||
won't really notice it unless you routinely have >2 I/O requests
|
||
pending at the SCSI level. The conventional wisdom (try it both ways)
|
||
applies.</P
|
||
><P
|
||
>And finally I <EM
|
||
>do</EM
|
||
> have to make a
|
||
disclaimer. Much of the stuff above is shameless simplification. In
|
||
reality, high-performance disks are very complicated
|
||
beasties. They run little mini-operating systems that are most
|
||
comfortable if they have 10-20 I/O requests pending <EM
|
||
>at the
|
||
same time</EM
|
||
>. Under those circumstances, the amortized global
|
||
latencies are much reduced, though any single request may experience
|
||
<EM
|
||
>longer</EM
|
||
> latencies than if it were the only one
|
||
pending. The only really valid analysis are stochastic-process models,
|
||
which we <EM
|
||
>really</EM
|
||
> don't want to get into
|
||
here. :-)</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="economizing"
|
||
></A
|
||
>5. But What If I'm Economizing?</H1
|
||
><P
|
||
>If you are economizing, here's a simple rule:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
><EM
|
||
>Do</EM
|
||
> buy a CPU/motherboard one or two
|
||
levels lower than commercial state of the art.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>For best value, look in the <EM
|
||
>middle</EM
|
||
> of the
|
||
current range of available processors. On the desktop, in late 2007, that
|
||
means a CPU costing perhaps $75 to $200, not the latest and greatest quad
|
||
core marvels selling for several times that!</P
|
||
><P
|
||
>Why? Because of the way manufacturers' price-performance curves are
|
||
shaped. The top-of-line system is generally boob bait for corporate
|
||
executives and other people with more money than sense. Chances are the
|
||
system design is new and untried — if you're at the wrong point in the
|
||
technology cycle, the chip may even be a pre-production sample, or an early
|
||
production stepping with undiscovered bugs like the infamous FDIV problem
|
||
in early Pentiums. You don't need such troubles. Better to go with a
|
||
chip/motherboard combination that's been out for a while and is known good.
|
||
It's not like you really need the extra speed, after all.</P
|
||
><P
|
||
>Besides, if you buy one of these gold-plated systems, you're only
|
||
going to kick yourself three months later when the price plunges by
|
||
30%. Further down the product line there's been more real competition
|
||
and the manufacturer's margins are already squeezed. There's less
|
||
room for prices to fall, so you won't watch your new toy lose street
|
||
value so fast. Its price will still drop, but it won't plummet
|
||
sickeningly.</P
|
||
><P
|
||
>Again, bear in mind that the cheapest processor you can buy new today
|
||
is plenty fast enough for Linux. So if dropping back a speed level or
|
||
two brings you in under budget, you can do it with no regrets.</P
|
||
><P
|
||
>Consider one drive rather than two. This <EM
|
||
>will</EM
|
||
>
|
||
reduce overall system performance somewhat, but the cost saving as a
|
||
fraction of total system cost is often substantial.</P
|
||
><P
|
||
>Another easy economy measure is looking for repaired or reconditioned
|
||
parts with a warranty. These are often as good as new, and much
|
||
cheaper.</P
|
||
><P
|
||
>Your display is one of the areas where pinching pennies is
|
||
<EM
|
||
>not</EM
|
||
> a good idea. You're going to be looking at that
|
||
display for hours on end. You are going to be using the screen real estate
|
||
constantly. Buy the best quality, largest screen you possibly can — it
|
||
will be worth it.</P
|
||
><P
|
||
>Similarly, do not reduce the amount of RAM in your system too far. A
|
||
minimum of 4GB of RAM is helpful in desktop systems today.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="noise"
|
||
></A
|
||
>6. Noise Control and Heat Dissipation</H1
|
||
><P
|
||
>An increasingly critical aspect of machine design is handling the
|
||
waste heat and acoustic noise of operation. This may seem like a boring
|
||
subject, but cooling is a centrally important one if you want your machine
|
||
to last — because thermal stress from the electronics' own waste heat
|
||
is almost certainly what will kill it. You want that fatal moment to
|
||
happen later rather than sooner. On the other hand, cooling makes acoustic
|
||
noise, which human beings don't tolerate well.</P
|
||
><P
|
||
>This tradeoff bites harder than you think; it's the fundamental
|
||
reason that, despite my money-is-no-object premise in the Ultimate Linux
|
||
Box artcles, I didn't go to relatively exotic technologies like
|
||
liquid-cooled overclocking or RAID disk arrays for a performance boost.
|
||
Sure, they may initially look attractive — but overclocked chips and
|
||
banks of disk drives require massive cooling with lots of moving parts, and
|
||
it's not good to be trying to do creative work like programming with
|
||
anything that sounds quite so much like an idling jet engine sitting beside
|
||
one's desk.</P
|
||
><P
|
||
>In 2001 we had already reached the point at which the thermal load
|
||
vs. cooling-noise tradeoff is the effective limiting factor in the
|
||
performance of personal machines. Ten years ago, even low-end and medium
|
||
"server" machines differed from personal-PC designs in fairly important
|
||
ways (different processor and bus types, different speed ranges, etc.)
|
||
Nowadays specialized server architectures are in retreat at the high end of
|
||
the market and everything else looks like a PC. And the difference between
|
||
a "PC" and a "server" is mainly that servers live in server rooms, and are
|
||
allowed to have monster cases with lots of noisy fans.</P
|
||
><P
|
||
>So how do we manage this tradeoff for a personal, desktop or
|
||
desk-side machine? Careful choice of components and being willing to pay
|
||
some price premium for cool-running and low-noise characteristics can help
|
||
a lot. Even exceptionally clueful system integrators can't generally
|
||
afford to do this, because they're under constant competitive pressure to
|
||
cut price and costs by using generic components.</P
|
||
><P
|
||
>Reducing expected noise and heat in a design call for different
|
||
strategies. It's relatively easy to find decibel figures for the
|
||
noisemaking parts in a PC design. And, once you know a little basic
|
||
audiometry and a few basic rules of thumb, it's not hard to form a fair
|
||
estimate of your design's noisiness. Estimating a design's heat
|
||
dissipation is harder, partly because the waste-heat emission of a PC's
|
||
subsystems tends to vary in a more complex way than the acoustic emissions
|
||
of the mechanical parts. This means that you can and should try to design
|
||
ahead for low noise, but on the other hand expect to have to monitor for
|
||
heat-dissipation problems in your prototype and solve them by building
|
||
in more cooling.</P
|
||
><P
|
||
>Here's the basic audiometry you need to know to control your
|
||
design's noise emissions:</P
|
||
><P
|
||
>Sound is measured in <I
|
||
CLASS="firstterm"
|
||
>decibels</I
|
||
>, abbreviated dB,
|
||
relative to the threshold of audibility, "A". (Thus, sound levels above
|
||
that threshold are written "dBA".) The scale is logarithmic, with every
|
||
3dB increment roughly doubling sound intensity.</P
|
||
><P
|
||
>For sounds that are not phase-related, decibel levels add as a
|
||
logarithmic sum. Thus if X and Y are uncorrelated sound sources,</P
|
||
><P
|
||
CLASS="literallayout"
|
||
><br>
|
||
dBA(X + Y) = 10 * log(10 ^ (dBA(X)/10) + 10 ^ (dBA(Y)/10))<br>
|
||
</P
|
||
><P
|
||
>A consequence of the above formula is that dBA(X + Y) cannot be
|
||
more than 3dB above the greater of dBA(X) and dBA(Y) for uncorrelated
|
||
sources (6dB for perfectly correlated ones).</P
|
||
><P
|
||
>Sound from a point source decays by an inverse-square law,
|
||
roughly 6dB for each doubling of distance.</P
|
||
><P
|
||
>Important thresholds on the decibel scale:</P
|
||
><P
|
||
></P
|
||
><DIV
|
||
CLASS="variablelist"
|
||
><DL
|
||
><DT
|
||
>0 dBA</DT
|
||
><DD
|
||
><P
|
||
>Threshold of hearing</P
|
||
></DD
|
||
><DT
|
||
>20 dBA</DT
|
||
><DD
|
||
><P
|
||
>Rustling leaves, quiet living room</P
|
||
></DD
|
||
><DT
|
||
>30 dBA</DT
|
||
><DD
|
||
><P
|
||
>Quiet office</P
|
||
></DD
|
||
><DT
|
||
>40 dBA</DT
|
||
><DD
|
||
><P
|
||
>Quiet conversation</P
|
||
></DD
|
||
><DT
|
||
>45 dBA</DT
|
||
><DD
|
||
><P
|
||
>Threshold of distraction, according to EPA</P
|
||
></DD
|
||
><DT
|
||
>50 dBA</DT
|
||
><DD
|
||
><P
|
||
>Quiet street, average office noise</P
|
||
></DD
|
||
><DT
|
||
>60 dBA</DT
|
||
><DD
|
||
><P
|
||
>Normal conversation (1 foot distance)</P
|
||
></DD
|
||
><DT
|
||
>70 dBA</DT
|
||
><DD
|
||
><P
|
||
>Inside car</P
|
||
></DD
|
||
><DT
|
||
>75 dBA</DT
|
||
><DD
|
||
><P
|
||
>Loud singing (3 feet)</P
|
||
></DD
|
||
><DT
|
||
>80 dBA</DT
|
||
><DD
|
||
><P
|
||
>Typical home-stereo listening level</P
|
||
></DD
|
||
></DL
|
||
></DIV
|
||
><P
|
||
>The acoustic noise emitted by PCs is normally a combination of white
|
||
noise produced by airflow, high-frequency noise produced by bearing
|
||
friction in drive spindles and fans, and the constant frequency "blade
|
||
passing" noise that all propellers emit (the latter is often more intense
|
||
than white noise and bearing whine).</P
|
||
><P
|
||
>The best low-noise ball-bearing case fans emit around 20dBA.
|
||
Typical sleeve-bearing fans emit 30-50dBA.</P
|
||
><P
|
||
>According to the indispensable <A
|
||
HREF="http://tomshardware.com/"
|
||
TARGET="_top"
|
||
>Tom's Hardware site</A
|
||
>, you can expect
|
||
to cut at least 5dB off the interior noise level of the computer with a
|
||
good choice of case. We'll improve on that by adding sound-absorbing
|
||
material to the interior.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="laptops"
|
||
></A
|
||
>7. Special Considerations When Buying Laptops and Netbboks</H1
|
||
><P
|
||
>First, don't be misled by the term "netbook". A netbook is just a
|
||
small, low-priced, low-power laptop with relatively small solid-state
|
||
drives. Because the display and drive capacity are small, netbooks are
|
||
basically just good for email and surfing. If you're going to do coding
|
||
or even much word processing you'll need something more like a traditional
|
||
laptop or desktop.</P
|
||
><P
|
||
>Up until about 1999 the laptop market was completely crazy. The
|
||
technology was in a state of violent flux, with <SPAN
|
||
CLASS="QUOTE"
|
||
>"standards"</SPAN
|
||
>
|
||
phasing in and out and prices dropping like rocks. Things are beginning to
|
||
settle out a bit more now.</P
|
||
><P
|
||
>One sign of this change is that there are now a couple of laptop lines
|
||
that are clear best-of-breeds for reasons having as much to do with
|
||
good industrial design and ergonomics as the technical details of the
|
||
processor and display.</P
|
||
><P
|
||
>In lightweight machines, I was a big fan of the Sony VAIO line.
|
||
I owned one from early 1999 until it physically disintegrated under
|
||
the rigors of travel in late 2000, and could hardly imagine
|
||
switching. They weigh 3.5 pounds, give you an honest 3 hours of life
|
||
per detachable battery pack, have a very nice 1024x768 display, and
|
||
are just plain <EM
|
||
>pretty</EM
|
||
>. Their only serious
|
||
drawback is that they're not rugged, and often fall apart after
|
||
a year or so of use.</P
|
||
><P
|
||
>If you want a full-power laptop that can compete with or replace your
|
||
desktop machine, the Lenovo (formerly IBM) ThinkPad line is the bomb.
|
||
Capable, rugged, and nicely designed. I now use a ThinkPad X61, the
|
||
lightest and smallest machine in the line, and like it a lot.</P
|
||
><P
|
||
>These machines are not cheap, though. If you're trying to save
|
||
money by buying a no-name laptop, here are things to look for:</P
|
||
><P
|
||
>First: despite what you may believe, the most important aspect
|
||
of any laptop is <EM
|
||
>not</EM
|
||
> the CPU, or the disk, or the
|
||
memory, or the screen, or the battery capacity. It's the keyboard
|
||
feel, since unlike in a PC, you cannot throw the keyboard away and
|
||
replace it with another one unless you replace the whole computer.
|
||
<EM
|
||
>Never buy any laptop that you have not typed on for a couple
|
||
hours</EM
|
||
>. Trying a keyboard for a few minutes is not enough.
|
||
Keyboards have very subtle properties that can still affect whether
|
||
they mess up your wrists.</P
|
||
><P
|
||
>A standard desktop keyboard has keycaps 19mm across with 7.55mm
|
||
between them. If you plot frequency of typing errors against keycap size,
|
||
it turns out there's a sharp knee in the curve at 17.8 millimeters. Beware
|
||
of <SPAN
|
||
CLASS="QUOTE"
|
||
>"kneetop"</SPAN
|
||
> and <SPAN
|
||
CLASS="QUOTE"
|
||
>"palmtop"</SPAN
|
||
> machines, which
|
||
squeeze the keycaps a lot tighter and typically don't have enough oomph for
|
||
Unix anyway; you're best off with the "notebook" class machines that have
|
||
full-sized keys.</P
|
||
><P
|
||
>Second: with present flatscreens, 1920x1200 color is the best you're
|
||
going to do (and that is on a 17in widescreen, which translates to a large
|
||
notebook. On normal size notebooks, a maximum of 1440x900 is more common).
|
||
On travel machines like the Lenovo X serties, you're still stuck with
|
||
1024x768. If you want more than that (for X, for example) you have to
|
||
either fall back to a desktop or make sure there's an external-monitor port
|
||
on the laptop (and many laptops won't support higher resolution than the
|
||
flatscreen's).</P
|
||
><P
|
||
>Third: about those vendor-supplied time-between-recharge
|
||
figures; <EM
|
||
>don't believe them</EM
|
||
>. They collect those
|
||
from a totally quiescent machine, sometimes with the screen or hard
|
||
disk turned off. Under Windows, you'd be lucky to get half the endurance
|
||
they quote; under Unix, which hits the disk more often, it may be less
|
||
yet. Figures from magazine reviews are more reliable.</P
|
||
><P
|
||
>Fourth: You can now avoid many of the driver hassles involved in
|
||
getting some devices on your notebook to work (or week well) under Linux by
|
||
purchasing a notebook with Linux pre-installed. Dell has recently started
|
||
to make noise in this regard in the Linux community. Taking this approach
|
||
limits the set of notebooks you can consider, but the one you get is likely
|
||
to "just work" (including sound, useful capabilities like suspend/resume,
|
||
and even hotplugging of external displays and projectors) to a much higher
|
||
degree under Linux than others.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="howtobuy"
|
||
></A
|
||
>8. How to Buy</H1
|
||
><DIV
|
||
CLASS="sect2"
|
||
><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="whentobuy"
|
||
></A
|
||
>8.1. When to Buy</H2
|
||
><P
|
||
>It used to be that good configurations for Unix were what the market
|
||
called ‘server’ machines, with beefed-up I/O subsystems and
|
||
fast buses. No longer; today's ‘servers’ are monster boxes
|
||
with multiple power supplies and processors, gigabytes of memory, and
|
||
industrial-grade air cooling —they're not really suitable as personal
|
||
machines. A typical SCSI desktop workstation is as much as you'll
|
||
need.</P
|
||
><P
|
||
>Prices keep dropping, so there's a temptation to wait forever to
|
||
buy. A good way to cope with this is to configure your system on paper, get
|
||
a couple of initial estimates, then set a trigger price, below the
|
||
lowest one, at what you're willing to pay. Then watch and wait. When
|
||
the configuration cost hits your trigger price, place your order.</P
|
||
><P
|
||
>The advantage of this method is that it requires you to settle in your
|
||
mind, well in advance, what you're willing to pay for what you're
|
||
getting. That way, you'll buy at the earliest time you should, and
|
||
won't stress too much out afterwards as it depreciates.</P
|
||
><P
|
||
>Before you shop, do your homework. Publications like "Computer
|
||
Shopper" (and their web site at <A
|
||
HREF="http://www.computershopper.com"
|
||
TARGET="_top"
|
||
> http://www.computershopper.com</A
|
||
>) are invaluable for helping you
|
||
get a feel for prices and what clonemakers are doing. Another
|
||
excellent site is <A
|
||
HREF="http://www.computeresp.com"
|
||
TARGET="_top"
|
||
>ComputerESP</A
|
||
>.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="wheretobuy"
|
||
></A
|
||
>8.2. Where to Buy</H2
|
||
><P
|
||
>The most important where-to-buy advice is negative. Do
|
||
<EM
|
||
>not</EM
|
||
> go to a traditional, business-oriented
|
||
storefront dealership. Their overheads are high. So are their
|
||
prices.</P
|
||
><P
|
||
>Especially, run —do not walk —away from any outfit that
|
||
trumpets ‘business solutions’. This is marketing code for the
|
||
kind of place that will justify a heavy price premium by promising
|
||
after-sale service and training which, nine times out of ten, will turn out
|
||
to be nonexistent or incompetent. Sure, they'll give you plush carpeting
|
||
and a firm handshake from a guy with too many teeth and an expensive watch
|
||
—but did you really want to pay for that?</P
|
||
><P
|
||
>There are two major alternatives to storefront dealerships and one
|
||
minor one. The major ones are mail order and computer superstores.
|
||
The minor one is computer fairs.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="fairs"
|
||
></A
|
||
>8.3. Computer Fairs</H2
|
||
><P
|
||
>I used to be a big fan of hole-in-the-wall stores run by immigrants
|
||
from the other side of the International Date Line, but most of those
|
||
places have been driven out of the regular retail game by the superstores
|
||
and the Web. If you still have one in your neighborhood, you're lucky. I
|
||
do, as it happens, but that is now unusual; the only place you normally
|
||
find diaspora Chinese and Indians selling cheap PCs over the counter
|
||
anymore is at computer fairs. (Usually they're doing it to publicize an
|
||
Internet/mail-order business.)</P
|
||
><P
|
||
>You can find good loss-leader deals on individual parts at these
|
||
fairs (they're especially good places to buy disk drives cheap). But I call
|
||
them a minor alternative because it's hard to get a custom configuration
|
||
tuned for Unix built for you at a fair. So you end up, effectively, back
|
||
in the mail-order or Web channel.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="mailorder"
|
||
></A
|
||
>8.4. Mail Order</H2
|
||
><P
|
||
>Internet buying makes a lot of sense today for anyone with
|
||
more technical savvy than J. Random Luser in a suit. Even from no-name
|
||
vendors, parts and system quality tend to be high and consistent,
|
||
so conventional dealerships don't really have much more to offer than a
|
||
warm fuzzy feeling. Furthermore, competition has become so intense that
|
||
even Internet/mail-order vendors today have to offer not just lower prices
|
||
than ever before but warranty and support policies of a depth that would
|
||
have seemed incredible a few years back. For example, many bundle a year
|
||
of on-site hardware support with their medium- and high-end
|
||
<SPAN
|
||
CLASS="QUOTE"
|
||
>"business"</SPAN
|
||
> configurations for a very low premium over the bare
|
||
hardware.</P
|
||
><P
|
||
>Note, however, that assembling a system yourself out of parts is
|
||
<EM
|
||
>not</EM
|
||
> likely to save you money over dealing with the
|
||
Internet/mail-order systems houses. You can't buy parts at the volume they
|
||
do; the discounts they command are bigger than the premiums reflected in
|
||
their prices. The lack of any system warranty or support can also be a
|
||
problem even if you're expert enough to do the integration yourself —
|
||
because you also assume all the risk of defective parts and integration
|
||
problems.</P
|
||
><P
|
||
>Watch out for dealers (Spectrum Trading for one) who charge ridiculous
|
||
shipping fees. One of our spies reports he bought a hotswappable hard
|
||
disc drive tray that weighed about 3 lbs. and cost $250 and they
|
||
charged $25 to ship it UPS groud.</P
|
||
><P
|
||
>Don't forget that (most places) you can avoid sales tax by buying from an
|
||
out-of-state outfit, and save yourself 6-8% depending on where you
|
||
live. If you live near a state line, buying from a local outfit you can often
|
||
win, quite legally, by having the stuff shipped to a friend or relative just
|
||
over it. Best of all is a buddy with a state-registered dealer number; these
|
||
aren't very hard to get and confer not just exemption from sales tax but
|
||
(often) whopping discounts from the vendors. Hand him a dollar afterwards to
|
||
make it legal.</P
|
||
><P
|
||
>(Note: I have been advised that you shouldn't try the latter tactic in
|
||
Florida —they are notoriously tough on "resale license" holders).</P
|
||
><P
|
||
>(Note II: The Supreme Court has ruled that states may not tax
|
||
out-of-state businesses under existing law, but left the way open for
|
||
Congress to pass enabling legislation. Let's hope the mail-order
|
||
industry has good lobbyists.)</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="superstores"
|
||
></A
|
||
>8.5. Computer Superstores</H2
|
||
><P
|
||
>Big chain superstores like CompUSA give you a reasonable alternative
|
||
to the Web. And there are good reasons to explore it — these stores
|
||
buy and sell at volumes that allow them to offer prices not far above the
|
||
Web. (They make back a lot of their margin on computer games and small
|
||
accessories like mouse pads, cables, and floppy disks.)</P
|
||
><P
|
||
>Note, however: <EM
|
||
>Avoid Best Buy</EM
|
||
>. Horror stories
|
||
about them are legion — predatory salescritters, incompetent
|
||
service, routine bait-and-switch tactics.</P
|
||
><P
|
||
>One thing you should not buy remotely if you can avoid it is a
|
||
monitor. Monitors are subject to significant quality variations even
|
||
within the same make and model. Flatscreens haver this [roblem less than
|
||
CRTs did, but you don't want a flatscreen with dead pixels. So buy your
|
||
monitor face-to-face, picking the best out of three or four.</P
|
||
><P
|
||
>Another good argument for buying at a superstore is that you may
|
||
have to pay return postage if you ship a system back to the vendor. On a
|
||
big, heavy system, this can eat your initial price savings.</P
|
||
><P
|
||
>The only major problem with superstores is that the salespeople who
|
||
staff them aren't very bright or very clueful (it's a sort of Darwinian
|
||
reverse-selection effect; these are the guys who are fascinated by computer
|
||
technology but not smart enough to be techies). Most of them don't know
|
||
from Linux and are likely to push things like two-button mice that you
|
||
can't use. Use caution and check your system manifest.</P
|
||
><P
|
||
>But if you shop carefully and don't fall for one of their name-brand
|
||
"prestige" systems, you can get prices comparable to Internet/mail-order
|
||
with the comfort of knowing there's a trouble desk you can drive back to in
|
||
a pinch. (Also, you <EM
|
||
>can</EM
|
||
> see your monitor before you
|
||
buy!)</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="buying_tips"
|
||
></A
|
||
>8.6. Other Buying Tips</H2
|
||
><P
|
||
>You can often get out of paying tax just by paying cash,
|
||
especially at computer shows. You can always say you're going to ship
|
||
the equipment out of the state.</P
|
||
><P
|
||
>A lot of vendors bundle Windows and variable amounts of apps
|
||
with their hardware. If you tell them to lose all this useless cruft
|
||
they may shave $50 or $100 off the system price.</P
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="questions"
|
||
></A
|
||
>9. Questions You Should Always Ask Your Vendor</H1
|
||
><DIV
|
||
CLASS="sect2"
|
||
><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="warranty"
|
||
></A
|
||
>9.1. Minimum Warranty Provisions</H2
|
||
><P
|
||
>The weakest guarantee you should settle for in the mail-order
|
||
market should include:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>72-hour burn-in to avoid that sudden infant death
|
||
syndrome. (Also, try to find out if they do a power-cycling test and
|
||
how many repeats they do; this stresses the hardware much more than
|
||
steady burn-in.)</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>30 day money-back guarantee. Watch out for fine print
|
||
that weakens this with a restocking fee or limits it with
|
||
exclusions.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>1 year parts and labor guarantee (some vendors give 2
|
||
years).</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>1 year of 800 number tech support (many vendors give
|
||
lifetime support).</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>Additionally, many vendors offer a year of on-site service free. You
|
||
should find out who they contract the service to. Also be sure the free
|
||
service coverage area includes your site; some unscrupulous vendors weasel
|
||
their way out with <SPAN
|
||
CLASS="QUOTE"
|
||
>"some locations pay extra"</SPAN
|
||
>, which
|
||
translates roughly to <SPAN
|
||
CLASS="QUOTE"
|
||
>"through the nose if you're further away than
|
||
our parking lot"</SPAN
|
||
>.</P
|
||
><P
|
||
>If you're buying store-front, find out what they'll guarantee beyond
|
||
the above. If the answer is <SPAN
|
||
CLASS="QUOTE"
|
||
>"nothing"</SPAN
|
||
>, go somewhere
|
||
else.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="documention"
|
||
></A
|
||
>9.2. Documentation</H2
|
||
><P
|
||
>Ask your potential suppliers what kind and volume of documentation
|
||
they supply with your hardware. You should get, at minimum,
|
||
operations manuals for the motherboard and each card or peripheral;
|
||
also an IRQ list. Skimpiness in this area is a valuable clue that
|
||
they may be using no-name parts from Upper Baluchistan, which is not
|
||
necessarily a red flag in itself but should prompt you to ask more
|
||
questions.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="quality"
|
||
></A
|
||
>9.3. A System Quality Checklist</H2
|
||
><P
|
||
>There are various cost-cutting tactics a vendor can use which
|
||
bring down the system's overall quality. Here are some good questions
|
||
to ask:</P
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>If you're buying a factory-configured system, does it
|
||
have FCC certification? While it's not necessarily the case that a
|
||
non-certified system is going to spew a lot of radio-frequency
|
||
interference, certification is legally required — and becoming
|
||
more important as clock frequencies climb. Lack of that sticker may
|
||
indicate a fly-by-night vendor, or at least one in danger of being
|
||
raided and shut down! (For further discussion, see the section on <A
|
||
HREF="#rfi"
|
||
>Radio Frequency Interference</A
|
||
>
|
||
above.)</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Are the internal cable connectors keyed, so they can't
|
||
be put in upside down? This doesn't matter if you'll never, ever
|
||
<EM
|
||
>ever</EM
|
||
> need to upgrade or service your system.
|
||
Otherwise, it's pretty important; and, vendors who fluff this detail
|
||
may be quietly cutting other corners.</P
|
||
></LI
|
||
></UL
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="mailtips"
|
||
></A
|
||
>10. Things to Check when Buying</H1
|
||
><DIV
|
||
CLASS="sect2"
|
||
><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="tricks"
|
||
></A
|
||
>10.1. Tricks and Traps in Warranties</H2
|
||
><P
|
||
>Reading warranties is an art in itself. A few tips:</P
|
||
><P
|
||
>Beware the deadly modifier <SPAN
|
||
CLASS="QUOTE"
|
||
>"manufacturer's"</SPAN
|
||
> on a warranty;
|
||
this means you have to go back to the equipment's original
|
||
manufacturer in case of problems and can't get satisfaction from the
|
||
mail-order house. Also, manufacturer's warranties run from the date
|
||
<EM
|
||
>they</EM
|
||
> ship; by the time the mail-order house
|
||
assembles and ships your system, it may have run out!</P
|
||
><P
|
||
>Watch for the equally deadly <SPAN
|
||
CLASS="QUOTE"
|
||
>"We do not guarantee
|
||
compatibility"</SPAN
|
||
>. This gotcha on a component vendor's ad means you may
|
||
not be able to return, say, a video card that fails to work with your
|
||
motherboard.</P
|
||
><P
|
||
>Another dangerous phrase is <SPAN
|
||
CLASS="QUOTE"
|
||
>"We reserve the right to substitute
|
||
equivalent items"</SPAN
|
||
>. This means that instead of getting the
|
||
high-quality name-brand parts advertised in the configuration you just
|
||
ordered, you may get those no-name parts from Upper Baluchistan
|
||
— theoretically equivalent according to the spec sheets, but
|
||
perhaps more likely to die the day after the warranty expires.
|
||
Substitution can be interpreted as <SPAN
|
||
CLASS="QUOTE"
|
||
>"bait and switch"</SPAN
|
||
>, so most
|
||
vendors are scared of getting called on this. Very few will hold
|
||
their position if you press the matter.</P
|
||
><P
|
||
>Another red flag: <SPAN
|
||
CLASS="QUOTE"
|
||
>"Only warranted in supported
|
||
environments"</SPAN
|
||
>. This may mean they won't honor a warranty on a
|
||
non-Windows system at all, or it may mean they'll insist on installing the Unix
|
||
on disk themselves.</P
|
||
><P
|
||
>One absolute show-stopper is the phrase <SPAN
|
||
CLASS="QUOTE"
|
||
>"All sales are
|
||
final"</SPAN
|
||
>. This means you have <EM
|
||
>no</EM
|
||
> options if a
|
||
part doesn't work. Avoid any company with this policy.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="mail_questions"
|
||
></A
|
||
>10.2. Special Questions to Ask Web/Mail-Order
|
||
Vendors Before Buying</H2
|
||
><P
|
||
></P
|
||
><UL
|
||
><LI
|
||
><P
|
||
>Does the vendor have the part or system presently in
|
||
stock? Mail order companies tend to run with very lean inventories;
|
||
if they don't have your item in stock, delivery may take longer.
|
||
Possibly <EM
|
||
>much</EM
|
||
> longer.</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>Does the vendor pay for shipping? What's the delivery
|
||
wait?</P
|
||
></LI
|
||
><LI
|
||
><P
|
||
>If you need to return your system, is there a
|
||
restocking fee? and will the vendor cover the return freight? Knowing
|
||
the restocking fee can be particularly important, as they make keep
|
||
you from getting real satisfaction on a bad major part. Avoid dealing
|
||
with anyone who quotes more than a 15% restocking fee — and it's
|
||
a good idea, if possible, to avoid any dealer who charges a restocking
|
||
fee at all.</P
|
||
></LI
|
||
></UL
|
||
><P
|
||
>Warranties are tricky. There are companies whose warranties are
|
||
invalidated by opening the case. Some of those companies sell
|
||
upgradeable systems, but only authorized service centers can do
|
||
upgrades without invalidating the warranty. Sometimes a system is
|
||
purchased with the warranty already invalidated. There are vendors
|
||
who buy minimal systems and upgrade them with cheap RAM and/or disk
|
||
drives. If the vendor is not an authorized service center, the
|
||
manufacturer's warranty is invalidated. The only recourse in case of
|
||
a problem is the vendor's warranty. So beware!</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="payment"
|
||
></A
|
||
>10.3. Payment Method</H2
|
||
><P
|
||
>It's a good idea to pay with AmEx or Visa or MasterCard; that way you
|
||
can stop payment if you get a lemon, and may benefit from a
|
||
buyer-protection plan using the credit card company's clout (not all cards
|
||
offer buyer-protection plans, and some that do have restrictions which may
|
||
be applicable). However, watch for phrases like <SPAN
|
||
CLASS="QUOTE"
|
||
>"Credit card
|
||
surcharges apply"</SPAN
|
||
> or <SPAN
|
||
CLASS="QUOTE"
|
||
>"All prices reflect 3% cash
|
||
discount"</SPAN
|
||
> which mean you're going to get socked extra if you pay by
|
||
card.</P
|
||
><P
|
||
>Note that many credit-card companies have clauses in their
|
||
standard contracts forbidding such surcharges. You can (and should)
|
||
report such practices to your credit-card issuer. If you already paid
|
||
the surcharge, they will usually see to it that it is returned to you.
|
||
Credit-card companies will often stop dealing with businesses that
|
||
repeat such behavior.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect2"
|
||
><HR><H2
|
||
CLASS="sect2"
|
||
><A
|
||
NAME="vendors"
|
||
></A
|
||
>10.4. Which Clone Vendors to Talk To</H2
|
||
><DIV
|
||
CLASS="sect3"
|
||
><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="pans"
|
||
></A
|
||
>10.4.1. Some pans</H3
|
||
><P
|
||
><EM
|
||
>Gateway</EM
|
||
>: may also be a vendor to avoid.
|
||
Apparently their newer machines don't have parity bits in their
|
||
memories; memory is tested only on reboot. This is dubious design
|
||
even for Windows, and totally unacceptable for Unix.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect3"
|
||
><HR><H3
|
||
CLASS="sect3"
|
||
><A
|
||
NAME="AEN670"
|
||
></A
|
||
>10.4.2. Some picks</H3
|
||
><P
|
||
>In early August 2001 I designed an `Ultimate Linux Box' with Gary
|
||
Sandine and John Pearson of <A
|
||
HREF="http://lanm-pc.com"
|
||
TARGET="_top"
|
||
>Los Alamos
|
||
Computers</A
|
||
>; you can <A
|
||
HREF="http://www.catb.org/~esr/writings/ultimate-linux-box/"
|
||
TARGET="_top"
|
||
>read all about it</A
|
||
> These
|
||
guys know what they are doing and are fun to work with. If you need a
|
||
high-end Linux workstation, or your laboratory needs a computer cluster,
|
||
talk with them.</P
|
||
></DIV
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="AEN675"
|
||
></A
|
||
>11. After You Take Delivery</H1
|
||
><P
|
||
>Your configuration is custom and involves slightly unusual
|
||
hardware. Therefore, keep a copy of the configuration you wrote down,
|
||
and check it against the invoice and the actual delivered hardware.
|
||
If there is a problem, calling back your vendor right away will
|
||
maximize your chances of getting the matter settled quickly.</P
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="software"
|
||
></A
|
||
>12. Software to go with your hardware</H1
|
||
><P
|
||
>I used to maintain an entire separate FAQ on Unixes for 386/486 and
|
||
Pentium hardware. Times change, industries evolve, and I can now
|
||
replace that FAQ with just three words:</P
|
||
><P
|
||
><STRONG
|
||
>Go get Linux!</STRONG
|
||
></P
|
||
><DIV
|
||
CLASS="note"
|
||
><P
|
||
></P
|
||
><TABLE
|
||
CLASS="note"
|
||
WIDTH="100%"
|
||
BORDER="0"
|
||
><TR
|
||
><TD
|
||
WIDTH="25"
|
||
ALIGN="CENTER"
|
||
VALIGN="TOP"
|
||
><IMG
|
||
SRC="../images/note.gif"
|
||
HSPACE="5"
|
||
ALT="Note"></TD
|
||
><TD
|
||
ALIGN="LEFT"
|
||
VALIGN="TOP"
|
||
><P
|
||
>FreeBSD or OpenSolaris are currently niche choices, but if they
|
||
offer something you need that Linux doesn't, don't let me stop you from
|
||
trying one or both of them.</P
|
||
></TD
|
||
></TR
|
||
></TABLE
|
||
></DIV
|
||
></DIV
|
||
><DIV
|
||
CLASS="sect1"
|
||
><HR><H1
|
||
CLASS="sect1"
|
||
><A
|
||
NAME="links"
|
||
></A
|
||
>13. Other Resources on Building Linux PCs</H1
|
||
><P
|
||
>The <A
|
||
HREF="http://www.pctechguide.com/"
|
||
TARGET="_top"
|
||
>PC Tech Guide</A
|
||
>
|
||
offers pretty comprehensive descriptions of PC hardware technologies.</P
|
||
><P
|
||
>The <A
|
||
HREF="http://hawks.ha.md.us/hardware/"
|
||
TARGET="_top"
|
||
>Caveat
|
||
Emptor</A
|
||
> guide has an especially good section on evaluating
|
||
monitor specifications. </P
|
||
><P
|
||
>Anthony Olszewski's <A
|
||
HREF="http://www.computercraft.com/docs/pcbuild.html"
|
||
TARGET="_top"
|
||
> Assembling A
|
||
PC</A
|
||
> is an excellent guide to the perplexed. Not
|
||
Linux-specific.</P
|
||
><P
|
||
><A
|
||
HREF="http://www.sysdoc.pair.com/"
|
||
TARGET="_top"
|
||
>Tom's Hardware
|
||
Guide</A
|
||
> covers many hardware issues exhaustively. It is
|
||
especially good about CPU chips and motherboards. Full of ads and
|
||
slow-loading graphics, though.</P
|
||
><P
|
||
>The <A
|
||
HREF="http://www.sysopt.com"
|
||
TARGET="_top"
|
||
>System Optimization
|
||
Site</A
|
||
> has many links to other worthwhile sites for hardware
|
||
buyers.</P
|
||
><P
|
||
>Christopher B. Browne has a page on <A
|
||
HREF="http://linuxfinances.info/info/linuxvars.html#VARS"
|
||
TARGET="_top"
|
||
>Linux VARs</A
|
||
>
|
||
that build systems. He also recommends the <A
|
||
HREF="http://en.tldp.org/HOWTO/VAR-HOWTO.html"
|
||
TARGET="_top"
|
||
>Linux
|
||
VAR HOWTO</A
|
||
>.</P
|
||
><P
|
||
>There's a <A
|
||
HREF="http://www.aplus.net/docs/facts/the-ultimate-guide-to-building-your-own-pc.htm"
|
||
TARGET="_top"
|
||
>Building
|
||
Your Own PC</A
|
||
> page. It's more oriented towards building from parts
|
||
than this one. Less technical depth in most areas, but better coverage of
|
||
some including RAM, soundcards and motherboard installation. Features
|
||
nifty and helpful graphics, one of the better graphics-intensive pages I've
|
||
seen. However, the hardware-selection advice is out of date.</P
|
||
><P
|
||
>The <A
|
||
HREF="http://en.tldp.org/HOWTO/Hardware-HOWTO"
|
||
TARGET="_top"
|
||
>Linux Hardware
|
||
Database</A
|
||
> .</P
|
||
><P
|
||
>The <A
|
||
HREF="http://www.silentpcreview.com/"
|
||
TARGET="_top"
|
||
>Silent PC
|
||
Reviews</A
|
||
> site has lots of good material on building quiet PCs.</P
|
||
></DIV
|
||
></DIV
|
||
></BODY
|
||
></HTML
|
||
> |