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hwclock(5) [debian man page]

HWCLOCK(5)						   Debian Administrator's Manual						HWCLOCK(5)

NAME
hwclock - variables that affect the behaviour of the hwclock boot script DESCRIPTION
The /etc/default/rcS file contains variable settings in POSIX format: VAR=VAL Only one assignment is allowed per line. Comments (starting with '#') are also allowed. OPTIONS
The following variables can be set. BADYEAR This is used to specify that the hardware clock is incapable of storing years outside the range of 1994-1999. Set to yes if the hardware is broken or no if working correctly. HWCLOCKACCESS If the hardware clock is not accessible, set to no, in which case hwclock will not be run. Otherwise, set to yes. HWCLOCKPARS Additional options for hwclock. Unset by default. For example, this may be use to specify the machine hardware clock type for Alphas. HCTOSYS_DEVICE The hardware clock device you want to use. Defaults to rtc0. It should probably match the CONFIG_RTC_HCTOSYS_DEVICE kernel config option. AUTHOR
Roger Leigh <rleigh@debian.org> SEE ALSO
hwclock(8), rcS(5). Feb 2012 HWCLOCK(5)

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FAKE-HWCLOCK(8) 					      System Manager's Manual						   FAKE-HWCLOCK(8)

NAME
fake-hwclock - Control fake hardware clock SYNOPSIS
fake-hwclock [ command ] [ force ] BACKGROUND
Many embedded Linux systems do not have a functional hardware clock. Either they simply don't have a hardware clock at all or they have a hardware clock but it is not usable (e.g. because Linux doesn't know how to use it or because no battery is present). This can lead to time moving backwards to some default value (often 1970) when the system is rebooted. Since lots of software assumes that time only moves forward this is a bad thing. NTP can (and should where practical) be used to sync with an external timeserver but it is not available early in the boot process and may be unavailable for other reasons. DESCRIPTION
fake-hwclock sets and queries a fake "hardware clock" which stores the time in a file. This program may be run by the system administrator directly but is typically run by init (to load the time on startup and save it on shutdown) and cron (to save the time hourly). If no command is given then fake-hwclock acts as if the save command was used. COMMANDS
save Save the time to the file. load Load the time from the file. If force is specified fake-hwclock will move the clock either backwards or forwards. Otherwise it will only move it forwards. FILES
/etc/fake-hwclock.data The file used to store the time /etc/init.d/fake-hwclock The init script used to run fake-hwclock on startup and shutdown /etc/default/fake-hwclock Settings file for the init script. /etc/cron.hourly/fake-hwclock Cron job used to save the time hourly ENVIRONMENT VARIABLES
FILE set the file used by fake-hwclock RETURN VALUES
1 is returned for invalid commands. 0 is returned in all other cases. BUGS
This approach can only provide a crude approximation of what a real hardware clock provides. Use of NTP or another method to keep the time in sync is strongly advised. Debian 5 April 2012 FAKE-HWCLOCK(8)
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