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@(#)mem.4 6.2 (Berkeley) 5/16/86

C 4 mem, kmem - main memory .lg 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. Examining and patching device registers is likely to lead to unexpected results when read-only or write-only bits are present.

On ISA the I/O memory space begins at physical address 0x000a0000 and runs to 0x00100000. Per-process data for the current process is UPAGES long, and ends at virtual address 0xfe000000.

/dev/mem

/dev/kmem