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diff --git a/sag-0.6.1-www/sag-0.6.1.html/x2451.html b/sag-0.6.1-www/sag-0.6.1.html/x2451.html new file mode 100644 index 0000000..d03cfa5 --- /dev/null +++ b/sag-0.6.1-www/sag-0.6.1.html/x2451.html @@ -0,0 +1,161 @@ +<!DOCTYPE HTML PUBLIC "-//Norman Walsh//DTD DocBook HTML 1.0//EN"> +<HTML +><HEAD +><TITLE +>The hardware and software clocks</TITLE +><META +NAME="GENERATOR" +CONTENT="Modular DocBook HTML Stylesheet"><LINK +REL="HOME" +TITLE="The Linux System Administrators' Guide" +HREF="book1.html"><LINK +REL="UP" +TITLE="Keeping Time" +HREF="c2432.html"><LINK +REL="PREVIOUS" +TITLE="Keeping Time" +HREF="c2432.html"><LINK +REL="NEXT" +TITLE="Showing and setting time" +HREF="x2457.html"></HEAD +><BODY +BGCOLOR="#FFFFFF" +TEXT="#000000" +><DIV +CLASS="NAVHEADER" +><TABLE +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TH +COLSPAN="3" +ALIGN="center" +>The Linux System Administrators' Guide</TH +></TR +><TR +><TD +WIDTH="10%" +ALIGN="left" +VALIGN="bottom" +><A +HREF="c2432.html" +>Prev</A +></TD +><TD +WIDTH="80%" +ALIGN="center" +VALIGN="bottom" +>Chapter 11. Keeping Time</TD +><TD +WIDTH="10%" +ALIGN="right" +VALIGN="bottom" +><A +HREF="x2457.html" +>Next</A +></TD +></TR +></TABLE +><HR +ALIGN="LEFT" +WIDTH="100%"></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN2451" +>The hardware and software clocks</A +></H1 +><P +> A personal computer has a battery driven hardware clock. + The battery ensures that the clock will work even if the rest of + the computer is without electricity. The hardware clock can be + set from the BIOS setup screen or from whatever operating system + is running. </P +><P +> The Linux kernel keeps track of time independently from + the hardware clock. During the boot, Linux sets its own clock + to the same time as the hardware clock. After this, both clocks + run independently. Linux maintains its own clock because looking + at the hardware is slow and complicated. </P +><P +> The kernel clock always shows universal time. This way, + the kernel does not need to know about time zones at all. The + simplicity results in higher reliability and makes it easier + to update the time zone information. Each process handles time + zone conversions itself (using standard tools that are part of + the time zone package). </P +><P +> The hardware clock can be in local time or in universal + time. It is usually better to have it in universal time, + because then you don't need to change the hardware clock when + daylight savings time begins or ends (UTC does not have DST). + Unfortunately, some PC operating systems, including MS-DOS, + Windows, and OS/2, assume the hardware clock shows local time. + Linux can handle either, but if the hardware clock shows local + time, then it must be modified when daylight savings time begins + or ends (otherwise it wouldn't show local time). </P +></DIV +><DIV +CLASS="NAVFOOTER" +><HR +ALIGN="LEFT" +WIDTH="100%"><TABLE +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +><A +HREF="c2432.html" +>Prev</A +></TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +><A +HREF="book1.html" +>Home</A +></TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +><A +HREF="x2457.html" +>Next</A +></TD +></TR +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +>Keeping Time</TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +><A +HREF="c2432.html" +>Up</A +></TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +>Showing and setting time</TD +></TR +></TABLE +></DIV +></BODY +></HTML +>
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