NEC Direction SP B-Series, Руководство пользователя

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22 Glossary
serial interface
An interface that communicates information one bit at a time.
serial printer
A printer with a serial interface.
SGRAM
Synchronous Graphic Random Access Memory. A type of
DRAM used increasingly on video adapters and graphics
accelerators. Like SDRAM, SGRAM 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-ported (it can only be accessed by one
device at a time). However, it can open two memory pages at
once, which simulates the dual-port nature of other video RAM
technologies (access by two different devices simultaneously).
See VRAM and WRAM.
SIMM
Single Inline Memory Module. A small circuit board that can
hold a group of memory 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 II processors, you
need to use either DIMMs or pairs of SIMMs. See DIMMs.