LSI 20860 Host Adapter, Internal Scsi, Local Bus, Mainboard, Main Memory, Motherboard, Operating

Host Adapter	A circuit board or integrated circuit that provides a SCSI bus connection
	to the computer system.
Internal SCSI	A SCSI device installed inside the computer cabinet. These devices are
Device	connected in a continuous chain using an unshielded ribbon cable.
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.
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.
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).
Motherboard	See Mainboard. In some countries, the term Motherboard is not
	appropriate.
Operating	A program that organizes the internal activities of the computer and its
System (OS)	peripheral devices. An operating system performs basic tasks such as
	moving data to and from devices, and managing information in memory.
	It also provides the user interface.
PCI	Peripheral Component Interconnect. A local bus specification that allows
	connection of peripherals directly to computer memory. It bypasses the
	slower ISA and EISA buses.

Peripheral Devices

Pin-1 Orientation

Port Address

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 ensure proper alignment. Internal SCSI ribbon cables are sometimes not keyed, although they may have a colored strip indicating pin 1.

Also Port Number. The address through which commands are sent to a host adapter board. This address is assigned by the PCI bus.

A-2 Glossary of Terms and Abbreviations