NAME

mem, kmem − core memory

HP-UX COMPATIBILITY

Level: HP-UX/Optional

Origin: System III

Remarks: Not all HP−UX systems provide the mem and kmem files.  Programs which use them cannot expect to be portable from one HP-UX implementation to another. 

DESCRIPTION

Mem is a special file that is an image of the core 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 memory addresses.  References to non-existent locations cause errors to be returned. 

Examining and patching device registers is likely to lead to unexpected results when read-only or write-only bits are present. 

The file kmem is the same as mem except that kernel virtual memory rather than physical memory is accessed. 

Mem and kmem should always be protected so that only the super-user can read and write them, othewise both privacy and system security are compromised. 

FILES

/dev/mem, /dev/kmem

HARDWARE DEPENDENCIES

Series 500:
Mem and kmem are not provided. 

Series 200:
Memory does not begin at physical address 0. Instead, it occupies the upper portion of the physical address space from 0x900000 through 0xffffff, beginning at address 0xffffff and moving downward. Thus, if one megabyte of RAM is installed, it occupies addresses 0xf00000 through 0xffffff.

BUGS

On some machines memory files are accessed one byte at a time, an inappropriate method for some device registers. 

Hewlett-Packard  —  last mod. May 11, 2021