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. For details see the appropriate hardware technical reference manual for your computer.

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 0xe or greater than 0x3f 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 0xe or greater than 0x3f will result in an error, with errno set to ENXIO. Note that only the superuser may open the CMOS RAM device for writing, and that the CMOSWRITE ioctl will fail for any user other than the superuser.

FILES

/dev/cram

ADDED VALUE

This entry, supplied by INTERACTIVE Systems Corporation, contains enhancements to UNIX System V.