kmem(7) [osf1 man page]

kmem(7) 						 Miscellaneous Information Manual						   kmem(7)

NAME

       kmem - mapped kernel memory interface

DESCRIPTION

       The kmem character special device provides access to mapped kernel memory.

       Byte  addresses	in  kmem  are equivalent to mapped kernel memory addresses.  References to unmapped or user space addresses will return an
       error. Write accesses to console or PAL memory or to memory protected against writes will also return an error.

RESTRICTIONS

       Because memory is read and written in aligned quadwords (eight contiguous bytes), writing fewer than all the bytes in an  aligned  quadword
       is a read-modify-write operation that is not protected against writes to the same quadword.

       Device registers are accessed as aligned quadwords through kmem.

       The kmem file is not available as a memory mapped file.

FILES

       /dev/kmem

RELATED INFORMATION

       mem(7) delim off

																	   kmem(7)

MEM(4)							     Kernel Interfaces Manual							    MEM(4)

NAME

       mem, kmem - main memory

SYNOPSIS

       major device number(s):
	    raw: 1
       minor device encoding:
	    mem: 0;  kmem: 1;  null: 2

DESCRIPTION

       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 PDP-11s, the I/O page begins at location 0160000 of kmem and the per-process data segment for the current process begins at 0140000  and
       is USIZE clicks (64 bytes each) long.

FILES

       /dev/mem
       /dev/kmem
       /dev/MAKEDEV	   script to create special files
       /dev/MAKEDEV.local  script to localize special files

BUGS

       On PDP-11's, specifying an odd kernel or user address, or an odd transfer count is [generally] slower than using all even parameters.

       On machines with ENABLE/34(tm) memory mapping boards the I/O page can be accessed only through kmem.

3rd Berkeley Distribution					 January 28, 1988							    MEM(4)