HP A6829A PCI Dual Channel Ultra160 SCSI Host Bus Adapter Service and User Guide (May 2003)

Glossary
pin-1 orientation
Glossary 119
Low Voltage Differential (LVD) A robust
design methodology that improves power
consumption, data integrity, cable lengths,
and support for multiple devices while
providing a migration path for increased I/O
performance.
M
main memory The part of a computer’s
memory that is directly accessible by the
CPU (usually synonymous with RAM).
mainboard A large circuit board that holds
RAM, ROM, the microprocessor, custom
integrated circuits, and other components
that make a computer work. It also has
expansion slots for host bus adapters and
other plug-in boards.
megabyte (MByte) A measure of computer
storage equal to 1024 kilobytes.
motherboard See mainboard. In some
countries, the term motherboard is not
appropriate.
multi-tasking The initiation and control of
more than one sequence of operations. This
allows programs to operate in parallel.
multi-threading The simultaneous
accessing of data by more than one SCSI
device. This increases the aggregate data
throughput.
N
Non-Volatile Random Access Memory
(NVRAM ) An EEPROM used to store
configuration information.
O
operating system (OS) A program that
organizes the internal activities of the
computer and its peripheral devices. An
operating system performs basic tasks such
as moving data to and from devices and
managing information in memory. It also
provides the user interface.
P
parity checking A way to verify the
accuracy of data transmitted over the SCSI
bus. One bit in the transfer is used to make
the sum of all the 1 bits either odd or even
(for odd or even parity). If the sum is not
correct, an error message appears. SCSI uses
odd parity for data transfer rates less than
160 MB/s.
peripheral component interconnect
(PCI) A local bus specification that allows
connection of integrated peripheral
controller components, peripheral add-in
boards, and processor/memory systems.
peripheral devices A hardware device
(such as a video monitor, disk drive, printer,
or CD-ROM) used with a computer and
under the computer’s control. SCSI
peripherals are controlled through a SCSI
host bus adapter.
pin-1 orientation The alignment of pin 1
on a SCSI cable connector and the pin 1
position on the SCSI connector into which it
is inserted. External SCSI cables are keyed
to ensure proper alignment, but internal
SCSI ribbon cables might not be.