mirror of https://github.com/tLDP/LDP
2218 lines
105 KiB
XML
2218 lines
105 KiB
XML
<?xml version="1.0"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "docbook/docbookxx.dtd" [
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<!ENTITY ldpsite "http://www.tldp.org/">
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<!ENTITY howto "&ldpsite;HOWTO/">
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<!ENTITY mini-howto "&ldpsite;HOWTO/mini/">
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<!ENTITY home "http://www.catb.org/~esr/">
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]>
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<article id="index">
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<articleinfo>
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<title>The Unix Hardware Buyer HOWTO</title>
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<author>
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<firstname>Eric</firstname>
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<surname>Raymond</surname>
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<affiliation>
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<address>
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<email>esr@thyrsus.com</email>
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</address>
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</affiliation>
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</author>
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<abstract>
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<para>
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This is your one-stop resource for information about how to buy and
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configure generic PC hardware for cheap, powerful Unix systems.
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</para>
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</abstract>
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<revhistory id="revhistory">
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<revision>
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<revnumber>4.2</revnumber>
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<date>2010-04-11</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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DVD region-locking firmware is no longer an issue,
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</revremark>
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</revision>
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<revision>
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<revnumber>4.1</revnumber>
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<date>2009-07-01</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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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.
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</revremark>
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</revision>
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<revision>
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<revnumber>4.0</revnumber>
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<date>2007-11-02</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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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.
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</revremark>
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</revision>
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<revision>
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<revnumber>3.3</revnumber>
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<date>2007-18-13</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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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.
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</revremark>
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</revision>
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<revision>
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<revnumber>3.2</revnumber>
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<date>2004-10-28</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Fix and remove bad links.
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</revremark>
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</revision>
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<revision>
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<revnumber>3.1</revnumber>
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<date>2004-08-03</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Sound cards don't matter any more.
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</revremark>
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</revision>
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<revision>
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<revnumber>3.0</revnumber>
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<date>2004-02-21</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Power-protection stuff moved to UPS HOWTO. DIMM memory is
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gone. Tape drives don't make sense any more. Lots of the
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theory from my "Ultimate Linux Box"
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articles now lives here.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.4</revnumber>
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<date>2003-02-22</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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URL fixes.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.3</revnumber>
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<date>2002-08-06</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Buying at the low end isn't a lose anymore. I recommend
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Athlons. Nuked the section on video standards, EDID takes
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care of all that now. Also removed the section on older
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memory types. And keyboards, as the "ergonomic" ones all
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vanished along with the 1990s carpal-tunnel scare.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.2</revnumber>
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<date>2002-08-05</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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New section on DVD drives.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.1</revnumber>
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<date>2002-07-08</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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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.
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</revremark>
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</revision>
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<revision>
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<revnumber>2.0</revnumber>
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<date>2001-08-09</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Major update. Revisions based on Ultimate Linux Box experience.
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Caches are on-chip now. DDS4 tape drives are here.
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486 machines, CD caddies, and most non-DDS backup
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technologies are gone.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.1</revnumber>
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<date>2001-06-13</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Mid-2001 update.
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</revremark>
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</revision>
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<revision>
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<revnumber>1.0</revnumber>
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<date>2001-02-06</date>
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<authorinitials>esr</authorinitials>
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<revremark>
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Initial revision; but see the history in the introduction.
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</revremark>
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</revision>
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</revhistory>
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<!--
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This is the revision history for the old PC-Clone Unix Hardware Buyer's Guide:
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Nov 9 1994: We resume publication after a long hiatus.
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Dec 1 1994: More about Pentiums, laptops, and dual-bus boards.
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Dec 13 1994: Pre-Christmas roundup.
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Jun 29 1995: More about E-IDE and SCSI disks.
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Jul 22 1995: More about printers for Unix.
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Jan 20 1996: Major update, with new material on Trends in Disk Capacity,
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Modems, CD-ROMs, and many other topics.
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Mar 7 1996: Major update: Buying a Large Monitor. Also, new material
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on backup hardware, modems, printers.
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Jun 26 1996: More on caches and SCSI vs. IDE. Also a handy glossary
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of RAM-packaging terms.
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Oct 16 1996: Major Fall '96 update. New stuff on the bus wars, modems,
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benchmarks, lots of other topics.
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Dec 2 1996: New material on tape drives.
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Dec 10 1996: Reorganized and rewrote the `How To Buy' section.
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Dec 16 1996: Added material on GDI printers and a new `Links' section.
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Also more on RAM, ATX boards, video, and sound
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cards, 33.6 modems.
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Jan 8 1997: Minor update on ATX, printers, keyboards.
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Mar 12 1997: Minor update on multimedia.
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Apr 5 1997: Minor update on SCSI cables, Exabyte, keyboards.
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Aug 7 1997: Minor upgrade of power section.
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Aug 12 1997: Major update: new stuff on the processor market,
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memory, disk drives.
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Sep 12 1997: More good links.
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Sep 18 1997: Minor update on modems, keyboards, overall system prices.
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Dec 14 1997: Minor update on SCSI drives, and more resource links.
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Apr 21 1998: General update. Modem section still needs work.
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Jun 7 1998: More on modems: V.90, ADSL, K2, 56Flex.
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Jul 24 1998: More on DAT drives. Retired the 486 section and QIC
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material. Updated section on processors and motherboards.
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Aug 24 1998: New section on tuning your I/O subsystem.
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Aug 28 1998: More stuff on modems thanks to Frederic Joly.
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Sep 9 1998: Yet more on modems and I/O tuning. Fax section
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removed, apparently it was obsolete and incorrect.
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Dec 20 1998: Christmas update, various small fixes.
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Jun 11 1999: V90 modems have taken over.
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Jun 18 1999: Major Summer 1999 update. We're actually current now.
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Jun 23 1999: Minor update based on suggestions from Andrew Comech.
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Jun 26 1999: Minor update on How To Buy.
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Jul 9 1999: Added link to http://www.pc-disk.de/pcdisk.htm
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humongous disk database.
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Nov 6 1999: Minor updates on power protection and video cards.
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Apr 12 2000: Added link to the Linux Hardware Database.
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Jul 27 2000: Major update. AGP rules graphics now. Lots of
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stale stuff about older processors removed; those
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machines are just boat anchors now...
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-->
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</articleinfo>
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<sect1 id="intro"><title>Introduction</title>
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<sect2 id="purpose"><title>Purpose of this document</title>
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<para>The purpose of this document is to give you the background
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information you need to be a savvy buyer of Intel hardware for running
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Unix. It is aimed especially at hackers and others with the technical
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skills and confidence to go to the Internet/mail-order channel, but
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contains plenty of useful advice for people buying store-front
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retail.</para>
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<para>This document is maintained and periodically updated as a service to
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the net by Eric S. Raymond, who began it for the very best self-interested
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reason that he was in the market and didn't believe in plonking down
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several grand without doing his homework first (no, I don't get paid for
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this, though I have had a bunch of free software and hardware dumped on me
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as a result of it!). Corrections, updates, and all pertinent information
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are welcomed at <ulink
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url="mailto:esr@snark.thyrsus.com">esr@snark.thyrsus.com</ulink>. The
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editorial «we’ reflects the generous contributions of many
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savvy Internetters.</para>
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<para>If you email me questions that address gaps in the FAQ material,
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you will probably get a reply that says <quote>Sorry, everything I know
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about this topic is in the HOWTO</quote>. If you find out the
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<emphasis>answer</emphasis> to such a question, please share it with
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me for the HOWTO, so everyone can benefit.</para>
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<para>If you end up buying something based on information from this HOWTO,
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please do yourself and the net a favor; make a point of telling the vendor
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<quote>The HOWTO sent me</quote> or some equivalent. If we can show
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vendors that this HOWTO influences a lot of purchasing decisions, we get
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leverage to change some things that need changing.</para>
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<para>Note that in December 1996 I published an introductory article on
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building and tuning Linux systems summarizing much of the material in this
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HOWTO. It's <ulink url="&home;writings/lj-howtobuild.html">available
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here</ulink>. In 2001 I published an article on building the <ulink
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url="&home;/writings/ultimate-linux-box/">Ultimate Linux
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Box</ulink>.</para>
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<para>This Buyer's Guide actually dates back to 1992, when it was known as
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the <quote>PC-Clone Unix Hardware Buyer's Guide</quote>; this was before Linux
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took over my world :-). Before that, portions of it were part of
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a Unix Buyer's Guide that I maintained back in the 1980s on USENET.</para>
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<para>It may be a matter of historical interest that the page count of this
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guide peaked in mid-2001 and has been declining since. Video, sound, and
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other functions are migrating onto motherboards. Several bus types have
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disappeared, as have all the old-school backup technologies that couldn't
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scale up to match disk capacities, Spec sheets are getting
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simpler. Accordingly, there are parts that used to have whole sections to
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hemselves that I barely even write about anymore — mice, floppy disks,
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CD-ROM drives, and keyboards, for example, are utterly generic now,</para>
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<para>Another consequence of the technology stabilizing is also that I'm
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updating this guide less often than I used to. Years can now go by without
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the PC market changing in any fundamental way. </para>
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<para>In retrospect, the success of the ATX standard for motherboards in
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1998-1999 was probably the turning point. The PC industry has become
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sufficiently commoditized that your choices are now getting simpler rather
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than more complicated. This is a Good Thing.</para>
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</sect2>
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<sect2 id="newversions"><title>New versions of this document</title>
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<para>New versions of the Unix Hardware Buyer HOWTO will be periodically be
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uploaded to various Linux WWW and FTP sites, including the LDP home
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page.</para>
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<para>You can view the latest version of this on the World Wide Web via the
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URL <ulink
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url="&howto;Unix-Hardware-Buyer-HOWTO/">&howto;Unix-Hardware-Buyer-HOWTO/</ulink>.
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</para>
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</sect2>
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<sect2 id="feedback"><title>Feedback and corrections</title>
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<para>If you have questions or comments about this document, please
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feel free to mail Eric S. Raymond, at <ulink
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url="mailto:esr@thyrsus.com"> esr@thyrsus.com</ulink>. I welcome any
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suggestions or criticisms. If you find a mistake with this document,
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please let me know so I can correct it in the next
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version. Thanks.</para>
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</sect2>
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<sect2 id="resources"><title>Related resources</title>
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<para>You may also want to look at the read the <ulink
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url="&howto;Hardware-HOWTO.html">Hardware-HOWTO</ulink>. It lists hardware
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known to be compatible with Linux, and hardware known to be
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incompatible. I've also done a series of articles on <ulink
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url="&home;/writings/ultimate-linux-box/">The Ultimate Linux
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Box</ulink>.</para>
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</sect2>
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</sect1>
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<sect1 id="overview"><title>Overview of the Market</title>
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<para>The central fact about PC hardware is that de-facto hardware
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standards have created a commodity market with low entry barriers, lots of
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competitive pressure, and volume high enough to amortize a
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<emphasis>lot</emphasis> of development on the cheap.</para>
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<para>The result is that this hardware gives you lots of
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bang-per-buck, and it's getting both cheaper and better all the time.
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Furthermore, margins are thin enough that vendors have to be lean,
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hungry, and <emphasis>very</emphasis> responsive to the market to
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survive.</para>
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<para>One good general piece of advice is that you should avoid
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the highest-end new-technology systems (those not yet shipping in
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volume). The problem with the high end is that it usually
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carries a hefty <quote>prestige</quote> price premium, and may be a bit less
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reliable on average because the technology hasn't been through a lot
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of test/improve cycles.</para>
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<para>There used to be a real issue with low-end PCs as well,
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because there used to be a lot of dodgy crap PC components out
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there going into boxes made by vendors trying to save a few cents.
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That's not really a problem anymore. Market pressure has been
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very effective at raising reliability standards for even low-end
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components as the market has matured. It's actually hard to go
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wrong even buying at the bottom end of the market these days.</para>
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<para>I put together the first version of this guide around 1992;
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Unix-capable systems are now ten to twenty times cheaper than they were
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then. At today's prices, building your own system from parts no
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longer makes much sense at all —so this HOWTO is now more oriented
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towards helping you configure a whole system from a single vendor.</para>
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</sect1>
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<sect1 id="basics"><title>Buying the Basics</title>
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<para>In this section, we cover things to look out for that are more or less
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independent of price-performance tradeoffs, part of your minimum system
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for running Unix.</para>
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<para>Issues like your choice of disk, processor, and I/O bus (where there is
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a significant tradeoff between price and capability) are covered in the section
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on <link linkend="optimize">What To Optimize</link>.</para>
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<sect2><title>Things to Not Care About</title>
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<para>An effect of PC commoditization is that there aren lots of things
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you used to have to worry about that don't matter any more, because
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the market has completely flattened out. We list these here to get them
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out of the way.</para>
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<sect3 id="buswars"><title>Bus Wars</title>
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<para>The system bus is what ties all the parts of your machine together.
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This is an area in which progress has simplified your choices a lot. There
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used to be no fewer than <emphasis>four</emphasis> competing bus standards
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out there (ISA, EISA, VESA/VLB, PCI, and PCMCIA). Now there are
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effectively just <emphasis>two</emphasis> —PCI-X on servers, and PCIe
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for desktop/tower machines. Even PCI is now legacy technology, and the
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PCMCIA bus that seemed so important a few years back has been reduced to
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near-irrelevance by Ethernet, USB, and WiFi hardware built onto
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motherboards. The newcomer is PCIe, which is (in late 2007) a
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‘video-card-mostly’ bus, though it seems to be gaining in
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popularity for other uses too on mainstream desktop motherboards, whereas
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PCI-X is only found on higher end ‘server’ motherboards.
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</para>
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</sect3>
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<sect3 id="memory"><title>Memory</title>
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<para>Judging the memory-controller and cache design used to be one of the
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trickiest parts of evaluating a motherboard, but that stuff is all baked
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into the processor itself now. This removed a large source of latency and
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design variations. It also killed off the plethora of different RAM
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types that used to be out there.</para>
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<para>Today's advice is very simple. Make sure the memory is rated for your
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machine's bus speed, then buy as much as you can afford to stuff in your
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machine.</para>
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<note><para>DDR3 RAM is beginning to appear. Right now its extra expense
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over DDR2 is not worth paying, for all but extremely specialized needs. It
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is almost always <emphasis>far</emphasis> more useful to have 4GB of
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reasonably fast RAM, than 2GB of very fast RAM, in your
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machine.</para></note>
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<para>For more technical stuff on memory architectures, see <ulink
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url="http://www.kingston.com/tools/umg/default.asp">The Ultimate Memory
|
|
Guide</ulink> maintained by Kingston Technologies.</para>
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</sect3>
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<sect3 id="mice"><title>Keyboards and Mice</title>
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<para>Keyboards are mostly generic nowadays. One useful piece of advice is
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to not buy any desktop machine with <quote>Internet</quote> buttons on it;
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this is a sure sign of a PC that's an overpriced glitzy toy. Nowadays
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keyboards with a USB connector are the norm, rather than the older
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dedicated connectors; modern open-source Unixes handle these
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just fine.</para>
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<para>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
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|
your mouse when it starts up, so configuration is not a big deal any
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|
more.</para>
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<para>Some PC vendors, being Windows-oriented, still bundle two-button
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mice. Thus, you may have to buy your own three-button (or two button and a
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scroll wheel) mouse. Ignore the adspeak about dpi and pick a mouse or
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trackball that feels good to your hand.</para>
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<para>Your humble editor really, really likes the Logitech TrackMarble, an
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optical trackball that eliminates the chronic roller-fouling problems of
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the older TrackMan. They're well-supported by X, so any Linux or BSD will
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accept them.</para>
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</sect3>
|
|
<sect3 id="floppies"><title>Floppy Drives</title>
|
|
|
|
<para>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.
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|
You only ever see the 3.5-inch ‘hard-shell’ floppies with
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|
1.44MB capacity anymore.</para>
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<para>Bootable CD-ROMs killed off the last use of floppies, which was OS
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|
installation. So go ahead and settle for cheap Mitsumi and Teac floppy
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|
drives. There are no ‘premium’ floppy drives anymore. Nobody
|
|
bothers.</para>
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|
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<para>It's possible your system won't even include one. No loss.</para>
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|
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</sect3>
|
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<sect3 id="cdrom"><title>CD-ROM Drives</title>
|
|
|
|
<para>Standard CD-ROMs hold about 650 megabytes of read-only data in a
|
|
format called ISO-9660 (formerly <quote>High Sierra</quote>). 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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect3>
|
|
<sect3 id="backup"><title>Backup devices</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
</sect3>
|
|
</sect2>
|
|
|
|
<sect2 id="processor"><title>How To Pick Your Processor</title>
|
|
|
|
<para>Right now (early 2010), the chips to consider for running Unix are
|
|
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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Current CPUs are <emphasis>much</emphasis> 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.</para>
|
|
|
|
</sect2>
|
|
|
|
<sect2 id='twospindles'><title> One Disk or Two?</title>
|
|
|
|
<para>I usually build with two disks — one <quote>system</quote> disk
|
|
and one <quote>home</quote> 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.</para>
|
|
|
|
<para>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 <emphasis>did</emphasis> keep backups, right?).</para>
|
|
|
|
<para>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
|
|
<emphasis>do</emphasis> fail, so this approach (as well as good backups) is
|
|
well worth considering.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="cases"><title>Getting Down to Cases</title>
|
|
|
|
<para>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. </para>
|
|
|
|
<para>Look for the following quality features:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>Aluminum rather than steel. It's lighter and conducts
|
|
heat better.</para></listitem>
|
|
<listitem><para>Unobstructed air intake with at least one fan each
|
|
(in addition to the power supply and processor fans)</para></listitem>
|
|
<listitem><para>No sharp metal edges. You don't want to shred
|
|
your hands when you're tinkering with things.</para></listitem>
|
|
<listitem><para>There shouldn't be any hot spots (poor air flow).</para></listitem>
|
|
<listitem><para>Sturdy card clips. Some poorly-designed cases allow cards
|
|
to wiggle out of their slots under normal vibration.</para></listitem>
|
|
<listitem><para>Effective and easy to use mechanisms for attaching hard
|
|
drives, CD-ROM, CD-R/W, DVDs, etc.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="power"><title>Power Supplies and Fans</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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
|
|
<ulink url="http://www.papstplc.com/">Papst</ulink>.
|
|
</para>
|
|
|
|
</sect2>
|
|
<sect2 id="motherboards"><title>Motherboards</title>
|
|
|
|
<para>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
|
|
<quote>name</quote> 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.</para>
|
|
|
|
<para>Some good features to look for in a motherboard include:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>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!)</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>(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.)</para>
|
|
|
|
<para>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 <ulink
|
|
url="http://www.dtxpc.org/">DTX</ulink> specification for small-form-factor
|
|
PCs; it seems also to have sunk without trace.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Monitor and Video</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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?)</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>I used to carry a lot of material on different video standards,
|
|
interlacing, and flicker. That stuff is all obsolete now.</para>
|
|
|
|
<para>Here's what to look for on the monitor spec sheet:</para>
|
|
|
|
<itemizedlist> <listitem><para>Screen size and format. Usually measured in
|
|
diagonal inches. Most displays are now in a <quote>widescreen</quote>
|
|
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 <quote>19
|
|
inch</quote> widescreen monitor generally has considerably fewer pixels
|
|
than a <quote>19 inch</quote> 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.</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>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.</para>
|
|
</sect2>
|
|
<sect2 id="dvd"><title>DVD Drives</title>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="sound"><title>Sound Cards and Speakers</title>
|
|
|
|
<para>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 all these features:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>16-bit sampling (for 65536 dynamic levels rather
|
|
than 256).</para></listitem>
|
|
<listitem><para>Mono and stereo support.</para></listitem>
|
|
<listitem><para>Full-duplex mode.</para></listitem>
|
|
<listitem><para>Sampling rate of 44.1KHz (CD-quality).</para></listitem>
|
|
<listitem><para>MIDI interface via a standard 15-pin D-shell
|
|
connector.</para></listitem>
|
|
<listitem><para>RCA output jacks for headphones or speakers.</para></listitem>
|
|
<listitem><para>A microphone jack for sound input.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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 <ulink
|
|
url="http://www.alsa-project.org/main/index.php/Matrix:Main">ALSA Sound
|
|
Card Matrix</ulink>.</para>
|
|
|
|
<para>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 <quote>self-powered</quote>, 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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="modems"><title>Modems</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<note><para>If you live somewhere with <emphasis>really</emphasis> 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
|
|
<ulink url="http://www.usrobotics.com">U.S. Robotics</ulink> web site for
|
|
current product numbers and more detailed specifications.</para></note>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<sect3 id="modem_format"><title>Internal vs. External</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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
|
|
<quote>screaming-tty</quote> 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.</para>
|
|
|
|
<para>See <ulink url="http://linuxmafia.com/~rick/faq/">Rick's
|
|
Rants</ulink> for extended discussion of this point.</para>
|
|
|
|
</sect3>
|
|
<sect3 id="modem_pitfalls"><title>Pitfalls to Avoid</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>If the abbreviation <quote>RPI</quote> occurs anywhere on the box,
|
|
don't even consider buying the modem. RPI (Rockwell Protocol Interface) is
|
|
a proprietary <quote>standard</quote> 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.</para>
|
|
|
|
<para>Also avoid anything called a <quote>Windows Modem</quote> or
|
|
<quote>WinModem</quote>, <quote>HCF</quote>, or <quote>HSP</quote>; 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). </para>
|
|
|
|
<para>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".</para>
|
|
|
|
</sect3>
|
|
<sect3><title>Fax Modems</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Avoid <quote>Class 1</quote> and <quote>Class 2</quote> modems. Look
|
|
for <quote>Class 2.0</quote> for the full EIA-standard command set.</para>
|
|
|
|
<para>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:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term> V.29</term>
|
|
<listitem><para> CCITT standard for Group III fax encoding at 9600bps</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term> V.17</term>
|
|
<listitem><para> CCITT standard for Group III fax encoding at
|
|
14400bps</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>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:</para>
|
|
|
|
<para><firstterm>Class 1</firstterm> — base EIA standard for fax
|
|
control as extensions to the Hayes AT command set.</para>
|
|
|
|
<para><firstterm>Class 2.0</firstterm> — enhanced EIA standard
|
|
including compression, error correction, station ID and other
|
|
features.</para>
|
|
|
|
<para><firstterm>Class 2</firstterm> — marketroidian for anything
|
|
between Class 1 and Class 2.0. Different <quote>Class 2</quote> modems
|
|
implement different draft subsets of the 2.0 standard, so <quote>Class
|
|
2</quote> fax software won't necessarily drive any given <quote>Class
|
|
2</quote> modem.</para>
|
|
|
|
<para>There's also a proprietary Intel "standard" called CAS, Communicating
|
|
Applications Specification. Ignore it; only Intel products support it.</para>
|
|
</sect3>
|
|
</sect2>
|
|
<sect2 id="printers"><title>Printers</title>
|
|
|
|
<para>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!</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>(There used to be a problem with <quote>GDI printers</quote> and
|
|
<quote>WinPrinters</quote> 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.)</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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 <emphasis>lot</emphasis> of pixels on it. At
|
|
today's prices, paying the small premium for Postscript capability makes
|
|
sense.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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...)</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
</sect2>
|
|
|
|
<sect2 id="power_protection"><title>Power Protection</title>
|
|
|
|
<para>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 <ulink url="&howto;UPS-HOWTO">UPS
|
|
HOWTO</ulink> that provides more complete coverage of what used to be in
|
|
this section.</para>
|
|
</sect2>
|
|
|
|
<sect2 id="rfi"><title>Radio Frequency Interference</title>
|
|
|
|
<para>(Thanks to Robert Corbett <Robert.Corbett@Eng.Sun.COM> for
|
|
contributing much of this section)</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>FCC regulations recognize two classes of computer:</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
</sect1>
|
|
<sect1 id='optimize'><title>What To Optimize</title>
|
|
|
|
<sect2><title>First, add more memory</title>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2><title>Bus and Disk speeds</title>
|
|
|
|
<para>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
|
|
<citerefentry>
|
|
<refentrytitle>top</refentrytitle>
|
|
<manvolnum>1</manvolnum>
|
|
</citerefentry>
|
|
running for a while as you use your machine. Notice how seldom the CPU
|
|
idle percentage drops below 90%!</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>How does it translate into a recipe in 2010? Like this; if
|
|
you're building a hot rod,</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para><emphasis>Do</emphasis> buy a machine with the fastest
|
|
available "front-side" (e.g. processor-to-memory) bus.</para></listitem>
|
|
|
|
<listitem><para><emphasis>Do</emphasis> get the fastest SATA disks you can
|
|
get your hands on.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
</sect2>
|
|
<sect2 id="diskwars"><title>Optimizing your disk subsystem</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Of these, average seek time is <emphasis>much</emphasis> 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!</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="iotune"><title>Tuning Your I/O Subsystem</title>
|
|
|
|
<para><emphasis>(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.)</emphasis></para>
|
|
|
|
<para>Building a good I/O subsystem boils down to two major points:
|
|
<emphasis>pick matched components</emphasis> so you don't over-build any
|
|
piece without benefit, and <emphasis>construct the whole pipe such that
|
|
it can feed what your OS/application combo needs</emphasis>.</para>
|
|
|
|
<para>It's important to recognize that <quote>balance</quote> 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 <quote>big boys</quote> 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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.)</para>
|
|
|
|
<para>Let's look at the disks first. Whenever you seriously look at a
|
|
disk, <emphasis>get its data sheet</emphasis>. 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.</para>
|
|
|
|
<para>What you need to find out for a disk is:</para>
|
|
|
|
<orderedlist>
|
|
<listitem><para>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.</para></listitem>
|
|
|
|
<listitem><para>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).</para></listitem>
|
|
|
|
<listitem><para>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.)</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
</orderedlist>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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 <emphasis>this disk</emphasis>.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>And finally I <emphasis>do</emphasis> 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 <emphasis>at the
|
|
same time</emphasis>. Under those circumstances, the amortized global
|
|
latencies are much reduced, though any single request may experience
|
|
<emphasis>longer</emphasis> latencies than if it were the only one
|
|
pending. The only really valid analysis are stochastic-process models,
|
|
which we <emphasis>really</emphasis> don't want to get into
|
|
here. :-)</para>
|
|
|
|
</sect2>
|
|
</sect1>
|
|
<sect1 id='economizing'><title>But What If I'm Economizing?</title>
|
|
|
|
<para>If you are economizing, here's a simple rule:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para><emphasis>Do</emphasis> buy a CPU/motherboard one or two
|
|
levels lower than commercial state of the art.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>For best value, look in the <emphasis>middle</emphasis> 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!</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Consider one drive rather than two. This <emphasis>will</emphasis>
|
|
reduce overall system performance somewhat, but the cost saving as a
|
|
fraction of total system cost is often substantial.</para>
|
|
|
|
<para>Another easy economy measure is looking for repaired or reconditioned
|
|
parts with a warranty. These are often as good as new, and much
|
|
cheaper.</para>
|
|
|
|
<para>Your display is one of the areas where pinching pennies is
|
|
<emphasis>not</emphasis> 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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect1>
|
|
|
|
<sect1 id='noise'><title>Noise Control and Heat Dissipation</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Here's the basic audiometry you need to know to control your
|
|
design's noise emissions:</para>
|
|
|
|
<para>Sound is measured in <firstterm>decibels</firstterm>, 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.</para>
|
|
|
|
<para>For sounds that are not phase-related, decibel levels add as a
|
|
logarithmic sum. Thus if X and Y are uncorrelated sound sources,</para>
|
|
|
|
<literallayout>
|
|
dBA(X + Y) = 10 * log(10 ^ (dBA(X)/10) + 10 ^ (dBA(Y)/10))
|
|
</literallayout>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>Sound from a point source decays by an inverse-square law,
|
|
roughly 6dB for each doubling of distance.</para>
|
|
|
|
<para>Important thresholds on the decibel scale:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>0 dBA</term>
|
|
<listitem><para>Threshold of hearing</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>20 dBA</term>
|
|
<listitem><para>Rustling leaves, quiet living room</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>30 dBA</term>
|
|
<listitem><para>Quiet office</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>40 dBA</term>
|
|
<listitem><para>Quiet conversation</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>45 dBA</term>
|
|
<listitem><para>Threshold of distraction, according to EPA</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>50 dBA</term>
|
|
<listitem><para>Quiet street, average office noise</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>60 dBA</term>
|
|
<listitem><para>Normal conversation (1 foot distance)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>70 dBA</term>
|
|
<listitem><para>Inside car</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>75 dBA</term>
|
|
<listitem><para>Loud singing (3 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>80 dBA</term>
|
|
<listitem><para>Typical home-stereo listening level</para></listitem>
|
|
</varlistentry>
|
|
<!--
|
|
<varlistentry>
|
|
<term>85 dBA</term>
|
|
<listitem><para>Pushing a lawnmower over grass</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>88 dBA</term>
|
|
<listitem><para>Motorcycle (30 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>90 dBA</term>
|
|
<listitem><para>Food Blender (3 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>94 dBA</term>
|
|
<listitem><para>Subway (inside)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>100 dBA</term>
|
|
<listitem><para>Diesel truck (30 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>107 dBA</term>
|
|
<listitem><para>Power mower (3 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>115 dBA</term>
|
|
<listitem><para>Pneumatic riveter (3 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>117 dBA</term>
|
|
<listitem><para>Chainsaw (3 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>120 dBA</term>
|
|
<listitem><para>Amplified Rock and Roll (6 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>130 dBA</term>
|
|
<listitem><para>Jet plane (100 feet)</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>140 dBA</term>
|
|
<listitem><para>Gunshot, firecracker</para></listitem>
|
|
</varlistentry>
|
|
-->
|
|
</variablelist>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>The best low-noise ball-bearing case fans emit around 20dBA.
|
|
Typical sleeve-bearing fans emit 30-50dBA.</para>
|
|
|
|
<para>According to the indispensable <ulink
|
|
url="http://tomshardware.com/">Tom's Hardware site</ulink>, 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.</para>
|
|
</sect1>
|
|
|
|
<sect1 id="laptops"><title>Special Considerations When Buying Laptops and Netbboks</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Up until about 1999 the laptop market was completely crazy. The
|
|
technology was in a state of violent flux, with <quote>standards</quote>
|
|
phasing in and out and prices dropping like rocks. Things are beginning to
|
|
settle out a bit more now.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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 <emphasis>pretty</emphasis>. Their only serious
|
|
drawback is that they're not rugged, and often fall apart after
|
|
a year or so of use.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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:</para>
|
|
|
|
<para>First: despite what you may believe, the most important aspect
|
|
of any laptop is <emphasis>not</emphasis> 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.
|
|
<emphasis>Never buy any laptop that you have not typed on for a couple
|
|
hours</emphasis>. 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.</para>
|
|
|
|
<para>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 <quote>kneetop</quote> and <quote>palmtop</quote> 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.</para>
|
|
|
|
<para>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).</para>
|
|
|
|
<para>Third: about those vendor-supplied time-between-recharge
|
|
figures; <emphasis>don't believe them</emphasis>. 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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect1>
|
|
|
|
<sect1 id="howtobuy"><title>How to Buy</title>
|
|
|
|
<sect2 id="whentobuy"><title>When to Buy</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>Before you shop, do your homework. Publications like "Computer
|
|
Shopper" (and their web site at <ulink
|
|
url="http://www.computershopper.com">
|
|
http://www.computershopper.com</ulink>) are invaluable for helping you
|
|
get a feel for prices and what clonemakers are doing. Another
|
|
excellent site is <ulink
|
|
url="http://www.computeresp.com">ComputerESP</ulink>.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="wheretobuy"><title>Where to Buy</title>
|
|
|
|
<para>The most important where-to-buy advice is negative. Do
|
|
<emphasis>not</emphasis> go to a traditional, business-oriented
|
|
storefront dealership. Their overheads are high. So are their
|
|
prices.</para>
|
|
|
|
<para>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?</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="fairs"><title>Computer Fairs</title>
|
|
|
|
<para>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.)</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="mailorder"><title>Mail Order</title>
|
|
|
|
<para>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
|
|
<quote>business</quote> configurations for a very low premium over the bare
|
|
hardware.</para>
|
|
|
|
<para>Note, however, that assembling a system yourself out of parts is
|
|
<emphasis>not</emphasis> 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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>(Note: I have been advised that you shouldn't try the latter tactic in
|
|
Florida —they are notoriously tough on "resale license" holders).</para>
|
|
|
|
<para>(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.)</para>
|
|
|
|
</sect2>
|
|
<sect2 id="superstores"><title>Computer Superstores</title>
|
|
|
|
<para>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.)</para>
|
|
|
|
<para>Note, however: <emphasis>Avoid Best Buy</emphasis>. Horror stories
|
|
about them are legion — predatory salescritters, incompetent
|
|
service, routine bait-and-switch tactics.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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 <emphasis>can</emphasis> see your monitor before you
|
|
buy!)</para>
|
|
|
|
</sect2>
|
|
<sect2 id="buying_tips"><title>Other Buying Tips</title>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>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.</para>
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="questions"><title>Questions You Should Always Ask Your Vendor</title>
|
|
|
|
<sect2 id="warranty"><title>Minimum Warranty Provisions</title>
|
|
|
|
<para>The weakest guarantee you should settle for in the mail-order
|
|
market should include:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>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.)</para></listitem>
|
|
|
|
<listitem><para>30 day money-back guarantee. Watch out for fine print
|
|
that weakens this with a restocking fee or limits it with
|
|
exclusions.</para></listitem>
|
|
|
|
<listitem><para>1 year parts and labor guarantee (some vendors give 2
|
|
years).</para></listitem>
|
|
|
|
<listitem><para>1 year of 800 number tech support (many vendors give
|
|
lifetime support).</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>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 <quote>some locations pay extra</quote>, which
|
|
translates roughly to <quote>through the nose if you're further away than
|
|
our parking lot</quote>.</para>
|
|
|
|
<para>If you're buying store-front, find out what they'll guarantee beyond
|
|
the above. If the answer is <quote>nothing</quote>, go somewhere
|
|
else.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="documention"><title>Documentation</title>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="quality"><title>A System Quality Checklist</title>
|
|
|
|
<para>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:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>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 <link
|
|
linkend="rfi">Radio Frequency Interference</link>
|
|
above.)</para></listitem>
|
|
|
|
<listitem><para>Are the internal cable connectors keyed, so they can't
|
|
be put in upside down? This doesn't matter if you'll never, ever
|
|
<emphasis>ever</emphasis> need to upgrade or service your system.
|
|
Otherwise, it's pretty important; and, vendors who fluff this detail
|
|
may be quietly cutting other corners.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="mailtips"><title>Things to Check when Buying</title>
|
|
|
|
<sect2 id="tricks"><title>Tricks and Traps in Warranties</title>
|
|
|
|
<para>Reading warranties is an art in itself. A few tips:</para>
|
|
|
|
<para>Beware the deadly modifier <quote>manufacturer's</quote> 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
|
|
<emphasis>they</emphasis> ship; by the time the mail-order house
|
|
assembles and ships your system, it may have run out!</para>
|
|
|
|
<para>Watch for the equally deadly <quote>We do not guarantee
|
|
compatibility</quote>. 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.</para>
|
|
|
|
<para>Another dangerous phrase is <quote>We reserve the right to substitute
|
|
equivalent items</quote>. 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 <quote>bait and switch</quote>, so most
|
|
vendors are scared of getting called on this. Very few will hold
|
|
their position if you press the matter.</para>
|
|
|
|
<para>Another red flag: <quote>Only warranted in supported
|
|
environments</quote>. 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.</para>
|
|
|
|
<para>One absolute show-stopper is the phrase <quote>All sales are
|
|
final</quote>. This means you have <emphasis>no</emphasis> options if a
|
|
part doesn't work. Avoid any company with this policy.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="mail_questions"><title>Special Questions to Ask Web/Mail-Order
|
|
Vendors Before Buying</title>
|
|
|
|
<itemizedlist>
|
|
<listitem><para>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 <emphasis>much</emphasis> longer.</para></listitem>
|
|
|
|
<listitem><para>Does the vendor pay for shipping? What's the delivery
|
|
wait?</para></listitem>
|
|
|
|
<listitem><para>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.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>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!</para>
|
|
|
|
</sect2>
|
|
<sect2 id="payment"><title>Payment Method</title>
|
|
|
|
<para>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 <quote>Credit card
|
|
surcharges apply</quote> or <quote>All prices reflect 3% cash
|
|
discount</quote> which mean you're going to get socked extra if you pay by
|
|
card.</para>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect2>
|
|
<sect2 id="vendors"><title>Which Clone Vendors to Talk To</title>
|
|
|
|
<sect3 id="pans"><title>Some pans</title>
|
|
|
|
<para><emphasis>Gateway</emphasis>: 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.</para>
|
|
|
|
</sect3>
|
|
<sect3><title>Some picks</title>
|
|
|
|
<para>In early August 2001 I designed an `Ultimate Linux Box' with Gary
|
|
Sandine and John Pearson of <ulink url="http://lanm-pc.com">Los Alamos
|
|
Computers</ulink>; you can <ulink
|
|
url="&home;writings/ultimate-linux-box/">read all about it</ulink> 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.</para>
|
|
|
|
</sect3>
|
|
</sect2>
|
|
</sect1>
|
|
<sect1><title> After You Take Delivery</title>
|
|
|
|
<para>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.</para>
|
|
|
|
</sect1>
|
|
<sect1 id="software"><title>Software to go with your hardware</title>
|
|
|
|
<para>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:</para>
|
|
|
|
<para><emphasis role="strong">Go get Linux!</emphasis></para>
|
|
|
|
<note><para>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.</para></note>
|
|
|
|
</sect1>
|
|
|
|
<sect1 id="links"><title>Other Resources on Building Linux PCs</title>
|
|
|
|
<para>The <ulink url="http://www.pctechguide.com/">PC Tech Guide</ulink>
|
|
offers pretty comprehensive descriptions of PC hardware technologies.</para>
|
|
|
|
<para>The <ulink url="http://hawks.ha.md.us/hardware/">Caveat
|
|
Emptor</ulink> guide has an especially good section on evaluating
|
|
monitor specifications. </para>
|
|
|
|
<para>Anthony Olszewski's <ulink
|
|
url="http://www.computercraft.com/docs/pcbuild.html"> Assembling A
|
|
PC</ulink> is an excellent guide to the perplexed. Not
|
|
Linux-specific.</para>
|
|
|
|
<para><ulink url="http://www.sysdoc.pair.com/">Tom's Hardware
|
|
Guide</ulink> covers many hardware issues exhaustively. It is
|
|
especially good about CPU chips and motherboards. Full of ads and
|
|
slow-loading graphics, though.</para>
|
|
|
|
<para>The <ulink url="http://www.sysopt.com">System Optimization
|
|
Site</ulink> has many links to other worthwhile sites for hardware
|
|
buyers.</para>
|
|
|
|
<para>Christopher B. Browne has a page on <ulink
|
|
url="http://linuxfinances.info/info/linuxvars.html#VARS">Linux VARs</ulink>
|
|
that build systems. He also recommends the <ulink
|
|
url="http://en.tldp.org/HOWTO/VAR-HOWTO.html">Linux
|
|
VAR HOWTO</ulink>.</para>
|
|
|
|
<para>There's a <ulink
|
|
url="http://www.aplus.net/docs/facts/the-ultimate-guide-to-building-your-own-pc.htm">Building
|
|
Your Own PC</ulink> 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.</para>
|
|
|
|
<para>The <ulink url="http://en.tldp.org/HOWTO/Hardware-HOWTO">Linux Hardware
|
|
Database</ulink> .</para>
|
|
|
|
<para>The <ulink url='http://www.silentpcreview.com/'>Silent PC
|
|
Reviews</ulink> site has lots of good material on building quiet PCs.</para>
|
|
</sect1>
|
|
</article>
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|
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