Specifications

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Appendix A Glossary
Socket AM2 A 940-pin socket used by many ver-
sions of the AMD Athlon 64, 64 X2, 64 FX,
Opteron, and Sempron processors.
Socket F A 1207-pin socket used by AMD Quad
FX platform processors to allow two dual-core
processors to work together in a quad-core plat-
form. Also called Socket 1207 FX by AMD and
Socket L1 by NVIDIA.
Socket T Early name for Socket 775. See also
Socket 775.
SODIMM (small outline dual inline memory
module) An industry-standard 144-pin memory
module designed for use primarily in laptop and
portable computers.
soft error An error in reading or writing data
that occurs sporadically, usually because of a tran-
sient problem, such as a power fluctuation.
software A series of instructions loaded in the
computer’s memory that instructs the computer in
how to accomplish a problem or task.
sound card An adapter card with sound-
generating capabilities.
South Bridge The Intel term for the lower-speed
component in the chipset that has always been a
single individual chip; it has been replaced in the
8xx-series chipsets by the ICH. The South Bridge
connects to the 33MHz PCI bus and contains the
IDE interface ports and the interface to the 8MHz
ISA bus (when present). It also typically contains
the USB interface and even the CMOS RAM and
real-time clock functions. The South Bridge con-
tains all the components that make up the ISA bus,
including the interrupt and DMA controllers. See
also chipset, ICH, MCH, and North Bridge.
SPI (SCSI parallel interface) Alternative name
for common SCSI standards. See also SCSI.
spindle The central post on which a disk drive’s
platters are mounted.
spindle count In notebook and laptop com-
puters with interchangeable drives, spindle count
refers to how many drives can be installed and used
at the same time.
splitter Used in DSL and cable modem service to
separate Internet signals from those used by the
existing telephone (DSL) or cable TV service.
SRAM (static random access memory) A
form of high-speed memory. SRAM chips do not
require a refresh cycle like DRAM chips and can be
made to operate at very high access speeds. SRAM
chips are very expensive because they normally
require six transistors per bit. This also makes the
chips larger than conventional DRAM chips. SRAM
is volatile, meaning it will lose data with no power.
SRAMs are often used for cache memory.
SSE (streaming SIMD extensions) The name
given by Intel for the 70 new MMX-type instruc-
tions added to the Pentium III processor when it
was introduced. See also MMX and SIMD.
ST-506/412 A hard disk interface invented by
Seagate Technology and introduced in 1980 with
the ST-506 5MB hard drive. IDE drives emulate this
disk interface.
stack An area of memory storage for temporary
values that normally are read in the reverse order
from which they are written. Also called last-in,
first-out (LIFO).
stackable hub or switch A hub or switch that
can be connected to another hub or switch to
increase its capacity. The uplink port on the exist-
ing hub or switch is used to connect the new hub
or switch.
stair-stepping Jagged raster representation of
diagonals or curves; corrected by antialiasing.
standby Defines an optional operating state
of minimal power reduction with the shortest
recovery time.
standby UPS A UPS that quickly switches into
operation during a power outage.
standoffs In a motherboard and case design,
small nonconductive spacers (usually plastic or
nylon) used to keep the underside of the mother-
board from contacting the metallic case, thus pre-
venting short circuits of the motherboard.
start/stop bits The signaling bits attached to a
character before and after the character is transmit-
ted during asynchronous transmission.
starting cluster The number of the first cluster
occupied by a file. Listed in the directory entry of
every file.
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