LSI SYM22801 - Manual (Page 69)

Glossary of Terms and Abbreviations B-3
Firmware Software that is permanently stored in ROM. Therefore, it can be
accessed during boot time.
Hard Disk A disk made of metal and permanently sealed into a drive cartridge. A
hard disk can store very large amounts of information.
Host The computer system in which a SCSI host adapter is installed. It uses
the SCSI host adapter to transfer information to and from devices
attached to the SCSI bus.
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.
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
PC’s. 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 busses. 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.
Mbyte Megabyte. A measure of computer storage equal to 1024 kilobytes.
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).