User Guide

A-2 Ampex 1308911-02
Model No.
Running Head
Glossary Glossary and Acronyms
Block Size The size, in bytes, of a block. For data blocks, there is one block size
within any given file section. Physical blocks have a single fixed size
of 1199840 bytes. Byte-stream interfaces have a data block size of 1
byte.
Buffer An area in computer memory where output data is stored pending a
write operation or where input data is received from a read operation.
See also Buffered I/O and Tape Drive Data Buffer.
Buffered I/O A way of improving I/O performance by temporarily storing data in
the tape drive data buffer rather than performing a physical I/O
operation for every application read or write call.
Buffered Read A read operation made using the readv call, which provides a set of
application data buffers into which the data is to be read.
Buffered Write A write operation made using the writev call, which provides a set of
application data buffers from which the data is to be written.
Byte-stream Mode Operating with a data block size of one. Byte-stream mode allows
transfers of any length and positioning to any byte on the tape.
Byte-swapping An I/O mode in which the order of the bytes in every pair is reversed.
Required for tapes used in drives that follow a byte-swapped protocol.
Capacity The amount of data that can be stored on a tape or tape partition. DD-
2 tapes are available in several capacities, including 25, 75, and 165
Gigabytes.
Cartridge A container with magnetic data storage tape inside. Cartridges used by
the DST family of tape drives are self-contained with two reels and
conform to DD-2 media specifications. The tape within a DD-2
cartridge does not require rewinding to be loaded or unloaded. The
term tape is frequently used to refer to a cartridge.
Cassette See Cartridge.
Checksum A value calculated from the contents of a block that provides a way of
checking whether the block contents have been corrupted.
Close A system call that releases the interface to a device established by the
open system call.
Coplanar Mode The DST tape drive mode in which a DST cartridge is engaged for
positioning.
Cumulative Data Block Number (CDBN)
The logical data block number counted from the beginning of partition
rather than the beginning of file.