mem(4) - NetBSD Manual Pages

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MEM(4)                NetBSD/x86 Kernel Interfaces Manual               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 cur-
     rently mapped to memory are allowed.

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


FILES

     /dev/mem
     /dev/kmem


HISTORY

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

NetBSD 10.1                   September 23, 2011                   NetBSD 10.1