NAME

mem, kmem — memory files

DESCRIPTION

The special file /dev/mem is an interface to the physical memory of the computer. Byte offsets in this file are interpreted as physical memory addresses. Reading and writing this file is equivalent to reading and writing memory itself. Only offsets within the bounds of /dev/mem are allowed.

Kernel virtual memory is accessed through the interface /dev/kmem in the same manner as /dev/mem. Only kernel virtual addresses that are currently mapped to memory are allowed.

On Acorn RiscPC, A7000(+) and RC7500 systems the I/O memory space (podule space and SuperIO) begins at physical address 0x03000000 and runs to 0x033fffff. On the RiscPC, EASI space runs from 0x08000000 to 0x0fffffff. The per-process data size for the current process is UPAGES long, and starts at VM_MAXUSER_ADDRESS.

FILES

/dev/mem

/dev/kmem

HISTORY

The mem, kmem files appeared in Version 6 AT&T UNIX.