225 lines
4.1 KiB
HTML
225 lines
4.1 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>About ACPI</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="ACPI: Advanced Configuration and Power Interface"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Translations"
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HREF="translations.html"><LINK
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REL="NEXT"
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TITLE="Why switch?"
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HREF="apmtoacpi.html"></HEAD
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><BODY
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CLASS="sect1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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SUMMARY="Header navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>ACPI: Advanced Configuration and Power Interface</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="translations.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="apmtoacpi.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="aboutacpi"
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></A
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>4. About ACPI</H1
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><P
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>In the world of power management ACPI is relatively new to the game.
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It was first released in 1996 by
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Compaq/Hewlett-Packard, Intel, Microsoft, Phoenix and Toshiba. These
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developers aimed to replace the previous industry standard for power
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management. Their <A
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HREF="http://www.acpi.info"
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TARGET="_top"
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>ACPI.info</A
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> site
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contains the official specifications, a list of companies that support ACPI
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and a number of other goodies. This is definitely not required reading, but
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may be of some interest to the insanely curious.</P
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><P
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>ACPI allows control of power management from within the
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operating system. The previous industry standard for power management, Advanced
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Power Management (APM), is controlled at the BIOS level. APM is activated
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when the system becomes idle--the longer the system idles, the less power it
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consumes (e.g. screen saver vs. sleep vs. suspend).
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In APM, the operating system has no knowledge of when the system will
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change power states.</P
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><P
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>ACPI can typically be configured from within the operating system.
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This is unlike APM where configuration often involves rebooting and
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entering the BIOS configuration screens to set parameters.</P
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><P
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>ACPI has several different software components:</P
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><P
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></P
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><UL
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><LI
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><P
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>a subsystem which controls hardware states and
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functions that may have previously been in the BIOS configuration</P
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><P
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>These states include:</P
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><P
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></P
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><UL
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><LI
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><P
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>thermal control</P
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></LI
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><LI
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><P
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>motherboard configuration</P
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></LI
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><LI
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><P
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>power states (sleep, suspend)</P
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></LI
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></UL
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></LI
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><LI
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><P
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>a policy manager, which is software that sits on top of
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the operating system and allows user input on the system
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policies</P
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></LI
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><LI
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><P
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>the ACPI also has device drivers that control/monitor devices such as a
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laptop battery, SMBus (communication/transmission path) and EC (embedded controller).</P
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></LI
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></UL
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><P
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>If you would like more information on power management in laptops, check out
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the resources on <A
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HREF="http://www.tuxmobil.org"
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TARGET="_top"
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>tuxmobil.org</A
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>.
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Specifically: <A
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HREF="http://tuxmobil.org/apm_linux.html"
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TARGET="_top"
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>Power Management
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with Linux - APM, ACPI, PMU</A
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> and the <A
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HREF="http://tuxmobil.org/Mobile-Guide.db/mobile-guide-p2c1-hardware-in-detail.html"
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TARGET="_top"
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>Hardware in Detail</A
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> section of the
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<A
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HREF="http://tuxmobil.org/Mobile-Guide.db/Mobile-Guide.html"
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TARGET="_top"
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>Linux
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Mobile Guide</A
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>.</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="translations.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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|
></TD
|
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|
><TD
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||
|
WIDTH="33%"
|
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|
ALIGN="right"
|
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VALIGN="top"
|
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|
><A
|
||
|
HREF="apmtoacpi.html"
|
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|
ACCESSKEY="N"
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|
>Next</A
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></TD
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|
></TR
|
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><TR
|
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|
><TD
|
||
|
WIDTH="33%"
|
||
|
ALIGN="left"
|
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|
VALIGN="top"
|
||
|
>Translations</TD
|
||
|
><TD
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||
|
WIDTH="34%"
|
||
|
ALIGN="center"
|
||
|
VALIGN="top"
|
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|
> </TD
|
||
|
><TD
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||
|
WIDTH="33%"
|
||
|
ALIGN="right"
|
||
|
VALIGN="top"
|
||
|
>Why switch?</TD
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||
|
></TR
|
||
|
></TABLE
|
||
|
></DIV
|
||
|
></BODY
|
||
|
></HTML
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>
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