MEM(4) | Device Drivers Manual (acorn32) | MEM(4)

# 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.

July 28, 1995 | NetBSD 9.0