MEM(4S) — SPECIAL FILES

NAME

mem, kmem, mbmem, mbio − main memory and I/O space

SYNOPSIS

None; included with standard system.

DESCRIPTION

These devices are special files that map memory and bus i/o space. They may be read, written, seek’ed and (except for kmem) mmap(2) ed.

Mem is a special file that is an image of the physical memory of the computer. It may be used, for example, to examine (and even to patch) the system.

Kmem is a special file that is an image of the kernel virtual memory of the system.

Mbmem is a special file that is an image of the Multibus memory of the system. Multibus memory is in the range from 0 to 1 Megabyte.

Mbio is a special file that is an image of the Multibus I/O space. Multibus I/O space extends from 0 to 64K.

When reading and writing mbmem and mbio odd counts or offsets cause byte accesses and even counts and offsets cause word accesses.

DIAGNOSTICS

None.

FILES

/dev/mem
/dev/kmem
/dev/mbmem
/dev/mbio