NAME

mem, kmem − main memory

DESCRIPTION

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

Byte addresses in mem are interpreted as physical memory addresses.  References to non-existent locations cause errors to be returned. 

The file kmem is the same as mem except that kernel virtual memory rather than physical memory is accessed.  Only kernel virtual addresses that are mapped to memory are allowed.  The file kUmem also refers to kernel virtual memory, but may be used to access areas mapped to UNIBUS address space and other I/O areas.  It forces all accesses to use word (short integer) accesses.  Examining and patching device registers is likely to lead to unexpected results when read-only or write-only bits are present. 

FILES

/dev/mem
/dev/kmem
/dev/kUmem

4th Berkeley Distribution  —  May 16, 1986