Open SCSI Integrator's Manual for NonStop S-Series Servers

Glossary
Open SCSI Integrator’s Manual for NonStop Servers—422988-002
Glossary-13
main memory
When the HP NonStop operating system is not running, communication must take place
over a low-level link. You can also communicate with a NonStop S-series server over a
low-level link when the operating system is running. See also service connection.
main memory. Data storage, specifically the chips that store the programs and data currently
in use by a processor. On Himalaya S-series servers, main memory is stored on the
processor and memory board (PMB) in the processor multifunction (PMF)
customer-replaceable unit (CRU) and is cleared when the system is powered off.
master service processor (MSP). A service processor (SP) that provides the basic service
processor functions as well as centralized system functions such as a console port, a
modem port for remote support functions, and system-load control. The enclosure
containing processors 0 and 1 (group 01) also contains a pair of MSPs.
MB. See megabyte (MB)
.
megabyte (MB). A unit of measurement equal to 1,048,576 bytes (1024 kilobytes). See also
gigabyte (GB)
and kilobyte (KB).
memory CRU. A customer-replaceable unit (CRU) containing dual inline memory modules
(DIMMs) that is installed in groups of four on the processor and memory board (PMB)
of the processor multifunction (PMF) CRU. Memory CRUs contain the processor
memory.
memory slot. One of eight slots for memory customer-replaceable units (CRUs) on the
processor and memory board (PMB). The slots are labeled MS1 through MS8.
MFIOB. See multifunction I/O board (MFIOB)
.
microcode. Any machine code or data that can run in a microprocessor.The two types of
microcode are volatile and nonvolatile. Volatile microcode is loaded into the volatile
random-access memory (RAM) of some types of printed wiring assemblies (PWAs) and
is not retained in a host PWA when power to the PWA is interrupted. For nonvolatile
microcode, see firmware
. See also millicode.
millicode. RISC instructions that implement various NonStop Series TNS low-level functions
such as exception handling, real-time translation routines, and library routines that
implement the TNS instruction set. Millicode is functionally equivalent to TNS
microcode. See also microcode
.
mirrored disk or volume. A pair of identical disk drives that are used together as a single
logical volume. One drive is considered primary and the other is called the mirror. Each
byte of data written to the primary drive is also written to the mirror drive; if the primary
drive fails, the mirror drive can continue operations.
module. A set of components sharing a common interconnection, such as a backplane. A
module is a subset of a group, and it is usually contained in an enclosure. In a Himalaya
S-series server, there is exactly one module in a group.