Specifications

SCSI Small computer system interface. A standard command specification and
command set that enables computers and peripherals to communicate with
each other. Sun's current of tape drives adhere to the SCSI-2 specification.
SCSI address The octal representation of the unique address (0-7) assigned to a narrow
device, or hexadecimal representation of the unique address (0-15) assigned
to a wide SCSI device.
Sequential access Sequential access devices store data sequentially in the order received. Tape
devices are the most common sequential access devices. By contrast, disk
drives are direct access devices, where data is stored in blocks, not
necessarily sequentially.
Single-ended SCSI devices can be single ended or differential. Single-ended devices
transmit signals by setting a line in the cable to a pattern of high and low
voltages in relation to a ground line. Differential devices send signals by
swapping over high and low states between two lines. This is more expensive
to implement, but reduces interference and allows longer cable lengths.
Single-ended and differential devices must not be mixed on one SCSI bus.
StackLink A mechanism that connects two or more Sun StorEdge L25 and/or L100 units
by enabling cartridges to be passed from a slot in one module to an available
drive in another module.
SWIS/S Single-ended, wide, intelligent SCSI/SBus host adapter.
Termination A SCSI bus (or cable) can have many devices plugged into it, but the end of
the cable furthest from the host computer must always be terminated to avoid
signals being reflected back and interfering with other signals. The terminator
both absorbs signals and provides power to the lines in the cable. For this
reason, it must itself be provided with power. Terminators can be of two
types, active and passive.
Tape library Type of tape autochanger that allows media to be accessed randomly.
Throughput A measure of sequential I/O performance, quoted in MB per second. See
IOPS.
Transfer rate The rate at which data is transferred from one device to another, for example
from the host computer to the tape drive during backup.
Just the Facts May 2003 40