cram(7) UNIX System V cram(7)
NAME
cram- CMOS RAM interface
DESCRIPTION
The cram driver provides an interface to the 64 bytes of battery backed-
up RAM. This memory contains information such as diagnostics and
configuration information.
Ioctl Calls
CMOSREAD
This call is used to read the contents of one of the CMOS RAM
locations. The argument to the ioctl is the address of a buffer of
two unsigned characters, the first of which is the address to be
read. The ioctl will fill in the second byte with the data. An
address less than 0 or greater than 63 will result in an error,
with errno set to ENXIO.
CMOSWRITE
This call is used to write a value into one of the CMOS RAM
locations. The argument to the ioctl is the address of a buffer of
two unsigned characters, the first of which is the address and the
second of which is the value to write at that address. An address
less than 0 or greater than 63 will result in an error, with errno
set to ENXIO. Note that only the super-user may open the CMOS RAM
device for writing, and that the CMOSWRITE ioctl will fail for any
other than the super-user.
FILES
/dev/cram
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