User Guide

A-8 Ampex 1308911-02
Model No.
Running Head
Glossary Glossary and Acronyms
Open A system call that establishes an interface to a device special file and
determines the characteristics of that interface within the bounds
defined by the device special file.
Pack Partition Layout
A tape format that packs as many partitions as possible onto a tape,
with system zones occurring anywhere within a partition. See also
Alternate, Stretch, and Waste partition layouts.
Partial Formatting A type of formatting in which only the first set of group A partitions
are formatted, followed by a single unformatted group B partition that
is formatted on-the-fly during I/O operations. Also called format group
A only. See Format.
Partition An area of fixed size for storing user data that is created when a tape
is formatted. Partitions subdivide a tape into logically contiguous,
independent areas, each having its own identification and each capable
of independent I/O operations. A partition may be physically non-
contiguous because of intervening system zone(s). See Volume.
Partition Context The partition component of the current position.
Pass-through Interface
An adapter-specific interface that allows applications to access the
DST tape drive using the drive adapter protocol. The DST Driver
provides this interface as a single ioctl function and does no
interpretation of command input or output.
Permissions A set of attributes that determine the types of access allowed to a given
operating system resource (such as a disk file).
Physical Beginning of Media (PBOM)
The location on tape where data recording begins.
Physical Beginning of Tape (PBOT)
The point where the transparent leader is joined to the beginning of
magnetic tape.
Physical Block The physical representation of data on a tape and the minimum unit in
which data can be written to or read from a tape. For DD-2 tapes, the
physical block size is 1199840 bytes (about 1.2 Mb) and fits within a
single double frame. See also Data Block and Double Frame.
Physical End of Media (PEOM)
The location on tape where data recording ends.
Physical End of Tape (PEOT)
The point where the transparent trailer is joined to the end of magnetic
tape.