clock -- Device Driver

Read the system clock
/dev/clock

The file  /dev/clock lets you  read and set  your system's clock.   It is a
part of the  driver mem, which manages memory; thus,  it has major number 0
and minor number 5.

The  real  time  clock occupies  the  first  14  bytes  of nonvolatile  RAM
(/dev/cmos).  The  difference between /dev/cmos and  /dev/clock is that the
latter device locks  the circuit during a read, so  that the clock will not
be updated as it is being read.

/dev/clock limits access to a 14-byte data area.  Attempts to read or write
beyond this limit will fail.   /dev/clock stores the system time in binary-
coded decimal (BCD).  For details on BCD, see the Lexicon entry for float.

The COHERENT command ATclock reads this device and writes to it.

See Also

ATclock,
cmos,
device drivers,
float

© 2012 by Stephen A. Ness