14 Glossary
serial printer
A printer with a serial interface.
SGRAM
Synchronous Graphic Random Access Memory. A type of DRAM used
increasing ly on video ada pters and gr aphics acce lerators. L ike SDRAM, SG RAM
can synchronize itself with the CPU bus clock at speeds of up to 100 MHz. In
addition, SGRAM uses several other techniques, such as masked writes and block
writes, to increase bandwidth for graphics-intensive functions. Unlike VRAM and
WRAM, SGRAM is single-port ed (it can only b e accessed b y o ne device at a t ime).
However, it c a n open two memor y pages at once, which simu la tes the dual-p ort
nature of other video RAM technologies (access by two different devices
simultan eously). S ee VRAM and WR AM.
SIMM
Single Inlin e Memory Modul e. A small circ u it board hold ing a group of me mor y
chips. Typically, SIMMs hold up to nine RAM chips. On PCs, the ninth chip is for
parity error checking. Unlike memory chips, SIMMs are measured in bytes rather
than bits. In today’s SIMMs, each chip holds 2 MB, so a single SIMM holds 16
MB. SIMMs are easier to install than individual memory chips. The bus from a
SIMM to the actual memory chips is 32 bits wide. A newer technology, called dual
in-line memory module (DIMM), provides a 64-bit bus. To take advantage of the
64-bit bus on Pentium processors, use either DIMMs or pairs of SIMMs. See
DIMMs.
Slot 1
The form factor for Intel Pentium processors. The Slot 1 package replaces the
Socket 7 and Socket 8 form factors used by previous Pentium processors. Slot 1 is a
242-pin daughter card slot that accepts a processor packaged as a Single Edge
Contact (SE C) cartridg e. A system boar d can have one or two Slot 1s. See SEC.
SMART
Self-Monitoring Analysis and Reporting Technology. A hard drive feature that
works in conju nction wit h s ystem soft wa re (for exa mple, LANDes k C lient
Manager, NEC Auto Backup) f or identifyin g a potential prob lem on the har d drive
and automatically backing up system files to a user-specified device, such as a tape
or Zip drive.
sound card
An expansion card designed for sound input and output. Sound cards can record
and play back d igital audio. Most also hav e a MIDI synthes izer, whic h means they
can play MIDI files; some also have MIDI inputs and outputs.
super video graphics array (SVGA)
A color bit-mapped graphics display standard that provides a resolution of 1024x
768 with up to 256 colors displayed simultaneously.
synchronous
Refers to protocols that require the clocks of the communicating machines to be
coordinat ed.