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Glossary of Terms and Abbreviations
Version 1.3
Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
Differential SCSI
A hardware configuration for connecting SCSI devices. It uses a pair of
lines for each signal transfer (as opposed to Single-Ended SCSI, which
references each SCSI signal to a common ground).
DMA
Direct Memory Access. A type of computer memory access that does not
involve the microprocessor. DMA often transfers data directly between
memory and an “intelligent” peripheral device.
DMA Bus
Master
A feature that allows a peripheral to control the flow of data to and from
system memory by blocks, as opposed to PIO (Programmed I/O), where
the processor is in control and the flow is by byte.
Domain
Validation
A software procedure in which a host queries a device to determine its
ability to communicate at the negotiated Ultra160 data rate.
DT Clocking
In DT Clocking, data is sampled on both the asserting and deasserting
edge of the REQ/ACK signal. DT clocking may only be implemented on
an LVD SCSI bus.
EEPROM
Electronically Erasable Programmable Read Only Memory. A memory
chip that typically stores configuration information. See NVRAM.
EISA
Extended Industry Standard Architecture. An extension of the 16-bit ISA
bus standard. It allows devices to perform 32-bit data transfers.
External SCSI
Device
A SCSI device installed outside the computer cabinet. These devices are
connected in a continuous chain using specific types of shielded cables.
Fast SCSI
A standard for SCSI data transfers. Fast SCSI allows a transfer rate of
up to 10 Mbytes/s over an 8-bit SCSI bus and up to 20 Mbytes/s over a
16-bit SCSI bus.
FCC
Federal Communications Commission.
Host Adapter
A circuit board or integrated circuit that provides a SCSI bus connection
to the computer system.
Internal SCSI
Device
A SCSI device installed inside the computer cabinet. These devices are
connected in a continuous chain using an unshielded ribbon cable.
ISA
Industry Standard Architecture. A type of computer bus used in most
PCs. ISA allows devices to send and receive data up to 16 bits at a time.
Kbyte
Kilobyte. A measure of computer storage equal to 1024 bytes.