Peripheral DevicesPin-1 Orientation

A piece of hardware (such as a video monitor, disk drive, printer, or CD-ROM) used with a computer and under the computer’s control. SCSI peripherals are controlled through a SCSI host adapter.

The alignment of pin 1 on a SCSI cable connector and the pin-1 position on the SCSI connector into which it is inserted. External SCSI cables are always keyed to insure proper alignment, but internal SCSI ribbon cables sometimes are not keyed.

PIO

Programmed Input/Output. A way the CPU can transfer data to and from

 

memory using the computer’s I/O ports. PIO is usually faster than DMA,

 

but requires CPU time.

Port Address

Also Port Number. The address through which commands are sent to a

 

host adapter board. This address is assigned by the PCI bus.

Port Number

See Port Address.

Queue Tags

A way to keep track of multiple commands that allow for increased

 

throughput on the SCSI bus.

RAM

Random Access Memory. The computer’s primary working memory in

 

which program instructions and data are stored and are accessible to the

 

CPU. Information can be written to and read from RAM. The contents of

 

RAM are lost when the computer is turned off.

RISC Core

LSI Logic SCSI chips contain a RISC (Reduced Instruction Set

 

Computer) processor, programmed through microcode scripts.

ROM

Read Only Memory. Memory from which information can be read but not

 

changed. The contents of ROM are not erased when the computer is

 

turned off.

SCAM

SCSI Configured AutoMatically. A method to automatically allocate SCSI

 

IDs using software when SCAM compliant SCSI devices are attached.

SCSI

Small Computer System Interface. A specification for a high performance

 

peripheral bus and command set. The original standard is referred to as

 

SCSI-1.

SCSI-2

The current SCSI specification which adds features to the original

 

SCSI-1 standard.

SCSI-3

The SCSI specification which adds features to the SCSI-2 standard.

Glossary of Terms and Abbreviations

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