adjtime - phpMan

ADJTIME_CONFIG(5) File Formats ADJTIME_CONFIG(5)

NAME
adjtime - information about hardware clock setting and drift factor

SYNOPSIS
/etc/adjtime

DESCRIPTION
The file /etc/adjtime contains descriptive information about the hardware mode clock set-
ting and clock drift factor. The file is read and write by hwclock; and read by programs
like rtcwake to get RTC time mode.

The file is usually located in /etc, but tools like hwclock(8) or rtcwake(8) allow to use
alternative location by command line options if write access to /etc is unwanted. The de-
fault clock mode is "UTC" if the file is missing.

The Hardware Clock is usually not very accurate. However, much of its inaccuracy is com-
pletely predictable - it gains or loses the same amount of time every day. This is called
systematic drift. The util hwclock keeps the file /etc/adjtime, that keeps some histori-
cal information. For more details see "The Adjust Function" and "The Adjtime File" sec-
tions from hwckock(8) man page.

The format of the adjtime file is, in ASCII.

First line
Three numbers, separated by blanks:

drift factor
the systematic drift rate in seconds per day (floating point decimal)

last adjust time
the resulting number of seconds since 1969 UTC of most recent adjustment or
calibration (decimal integer)

adjustment status
zero (for compatibility with clock(8)) as a decimal integer.

Second line
last calibration time
The resulting number of seconds since 1969 UTC of most recent calibration. Zero if
there has been no calibration yet or it is known that any previous calibration is
moot (for example, because the Hardware Clock has been found, since that calibra-
tion, not to contain a valid time). This is a decimal integer.

Third line
clock mode
Supported values are "UTC" or "LOCAL". Tells whether the Hardware Clock is set to
Coordinated Universal Time or local time. You can always override this value with
options on the hwclock command line.

FILES
/etc/adjtime