MEM(4S)

NAME
mem, kmem, zero, vme16d16, vme24d16, vme32d16, vme16d32, vme24d32, vme32d32, eeprom, atbus, sbus - main memory and bus I/O space

CONFIG
None; included with standard system.

DESCRIPTION

These devices are special files that map memory and bus I/O space. They may be read, written, seeked, and (except for kmem) memory-mapped. See read(2V), write(2V), mmap(2), and directory(3V).

  All Systems

mem is a special file that is an image of the physical memory of the computer. It may be used, for example, to examine (and even to patch) the system.

kmem is a special file that is an image of the kernel virtual memory of the system.

zero is a special file which is a source of private zero pages.

eeprom is a special file that is an image of the EEPROM or NVRAM.

  Sun-3 and Sun-4 Systems VMEbus
vme16d16 (also known as vme16) is a special file that is an image of VMEbus 16-bit addresses with 16-bit data. vme16 address space extends from 0 to 64K.

vme24d16 (also known as vme24) is a special file that is an image of VMEbus 24-bit addresses with 16-bit data. vme24 address space extends from 0 to 16 megabytes. The VME 16-bit address space overlaps the top 64K of the 24-bit address space.

vme32d16 is a special file that is an image of VMEbus 32-bit addresses with 16-bit data.

vme16d32 is a special file that is an image of VMEbus 16-bit addresses with 32-bit data.

vme24d32 is a special file that is an image of VMEbus 24-bit addresses with 32-bit data.

vme32d32 (also known as vme32) is a special file that is an image of VMEbus 32-bit addresses with 32-bit data. vme32 address space extends from 0 to 4 gigabytes. The VME 24-bit address space overlaps the top 16 megabytes of the 32-bit address space.

  Desktop SPARCsystems
The sbus is represented by a series of entries each of which is an image of a single sbus slot. The entries are named sbusn, where n is the slot number in hexadecimal. The number of sbus slots and the address range within each slot may vary between implementations.

  SPARCsystem 600MP Series
SPARCsystem 600MP series systems have both sbus and VMEbus as described above.

  Sun386i Systems

atbus is a special file that is an image of the AT bus space. It extends from 0 to 16 megabytes.

FILES
/dev/mem
/dev/kmem
/dev/zero
/dev/vme16d16
/dev/vme16
/dev/vme24d16
/dev/vme24
/dev/vme32d16
/dev/vme16d32
/dev/vme24d32
/dev/vme32d32
/dev/vme32
/dev/eeprom
/dev/atbus
/dev/sbus[0-3]

SEE ALSO
mmap(2), read(2V), write(2V), directory(3V)