NAME

mem, kmem − core memory

DESCRIPTION

Mem is a special file that is an image of the core 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 memory addresses.  References to non-existent locations cause errors to be returned. 

Examining and patching device registers is likely to lead to unexpected results when read-only or write-only bits are present. 

The file kmem is the same as mem except that kernel virtual memory rather than physical memory is accessed. 

On the PDP-11, the I/O page begins at location 0160000 of kmem and per-process data for the current process begins at 0140000. 

FILES

/dev/mem, /dev/kmem

BUGS

On the PDP-11, memory files are accessed one byte at a time, an inappropriate method for some device registers. 

May 16, 1980