Glossary 231
MACIO SBus-to-SCSI, Ethernet, and parallel interface. An ASIC that integrates three
functions: DMA, LANCE, and fast SCSI bus interface. Provides the interface
between the SBus and the following: SCSI, thick AUI Ethernet, TPE, and
parallel port.
MBus module A printed circuit board installed in an MBus slot of the system unit that
contains the CPU circuitry and components.
Mbyte Megabyte.
MDI Memory display interface.
MMU Memory management unit.
Monitor 1) Indicated by the > prompt. From the > prompt, you can boot the system,
continue the execution of a halted program, or enter the Forth Toolkit. If
disaster happened to your operating system, the Monitor automatically starts.
Monitor 2) A video display unit that is part of the SPARCstation 20 system. It is not the
same as a terminal.
MSBI MBus-to-SBus interface.
NVRAM Non-volatile RAM.
NVSIMM Non-volatile single in-line memory module.
on-board diagnostics Tests that allow you to test the network controller, diskette drive system,
memory, cache, system clock, and watch the network for valid Ethernet data
packets.
Pok Power ok. A signal from the power supply that is activated after DC voltages
are nominal.
POST Power-on self-test. Executes when you turn on the system power switch or
reboot the system and press and hold the keyboard Stop (L1) and D keys.
Initiated from the OpenBoot PROM, POST is a series of rudimentary tests
designed to verify that the major components on the system board and the
MBus modules installed within the system are operating properly.
printed circuit board Any board with electronic wiring etched on it.
PROM Programmable read-only memory.
RAM Random access memory.
RH Relative humidity.
ROM Read-only memory.
SBus card A printed circuit board installed in an SBus slot of the system unit.
SCC Serial communications controller.