LSI 8751D - Manual (Page 49)

Glossary of Terms and Abbreviations A-5
Peripheral
Devices 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.
Pin-1
Orientation 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.