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MEM(4)              NetBSD/acorn32 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 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.

NetBSD 2.1                       July 28, 1995                      NetBSD 2.1