pc

10.25 pc

11.25 pc

38

 

 

34.5 pc

 

IRQ

 

Interrupt Request Channel. A path through which a device can get the

 

 

 

immediate attention of the computer’s CPU. The PCI bus assigns an IRQ

 

 

 

path for each SCSI host adapter.

 

ISA

 

Industry Standard Architecture. A type of computer bus used in most

 

 

 

PCs. It 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.

 

Local Bus

 

A way to connect peripherals directly to computer memory. It bypasses

 

 

 

the slower ISA and EISA buses. PCI is a local bus standard.

 

Logical Unit

A subdivision, either logical or physical, of a SCSI device (actually the

 

 

 

place for the device on the SCSI bus). Most devices have only one logical

 

 

 

unit, but up to eight are allowed for each of the eight possible devices on

 

 

 

a SCSI bus.

 

LUN

 

Logical Unit Number. An identifier, zero to seven, for a logical unit.

 

LVDlink

 

Low Voltage Differential Link allows greater Ultra2 SCSI device

 

 

 

connectability and longer SCSI cables. LVDlink lowers the amplitude of

 

 

 

noise reflections and allows higher transmission frequencies. Detailed

 

pc

 

information may be found in Section 1.5, “Benefits of LVDlink

 

 

 

Technology.”

 

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 adapters and other expansion boards.

 

Main Memory

The part of a computer’s memory which is directly accessible by the CPU

 

 

 

(usually synonymous with RAM).

 

Mbyte

 

Megabyte. A measure of computer storage equal to 1024 kilobytes.

 

Motherboard

See Mainboard. In some countries, the term Motherboard is not

 

 

 

appropriate.

 

Multitasking

The executing of more than one command at the same time. This allows

 

 

 

programs to operate in parallel.

 

Multithreading

The simultaneous accessing of data by more than one SCSI device. This

 

 

 

increases the data throughput.

 

B-4

Glossary of Terms and Abbreviations