5190/5194 Modular Tape Subsystem Manual

Glossary
5190/5194 Modular Tape Subsystem Manual—426878-002
Glossary-9
tape drive CRU
tape drive CRU. A customer-replaceable unit (CRU) that consists of a tape drive, that
drive’s power supply, and a front panel with operator buttons. The tape drive CRU
facilitates quick and easy replacement of a drive that requires servicing.
tape dump. To copy the memory of a processor to tape.
tape label. A record at the beginning of a tape that identifies the tape volume and the files
it contains. Compaq NonStop Himalaya systems support two standard tape-label
formats: ANSI and IBM-MVS.
tape library. A collection of magnetic tapes that store information offline. Typically,
backups and infrequently used databases are stored in a tape library.
tape load. A system load. A tape load is the process of reading a system image tape (SIT)
and writing it to the system disk. Performing a tape load from a SIT to restore the
system image files to the $SYSTEM disk is generally not recommended. Perform a
tape load only with the advice of the Global Customer Support Center (GCSC) or your
service provider. Loading from a tape reinitializes the disk directory.
tape mark. A byte sequence written by the host system to separate sections of data
(individual files, for example) on a magnetic tape. A tape mark is sometimes called a
file mark.
TAPE object type. The Subsystem Control Facility (SCF) object type for all tape drives
attached to your system.
tape process. A running program that performs the actual reading of and writing to tapes.
The tape process also reads the labels on mounted tapes and sends the information to
$ZSVR, the server process for the labeled-tape subsystem.
terminator. A resistor connected to a signal wire in a bus or network for the purpose of
impedance matching to prevent reflections. SCSI chains, Ethernet cables, and some
LocalTalk wiring configurations require terminators.
TMDS. See Compaq Tandem Maintenance and Diagnostic System (TMDS).
TMF subsystem. See Compaq NonStop Transaction Management Facility (TMF)
subsystem.
track. A longitudinal (lengthwise) region of a tape on which data can be stored using
magnetic signals.
TSM package. See Compaq TSM package.
unit number. A number that represents a connection between a controller and a tape drive
on a Compaq NonStop K-series server. The unit number of a tape drive in a modular
tape subsystem is specified when the tape drive is added to the system configuration
using either the Configuration Utility Program (COUP) or the Subsystem Control
Facility (SCF).