Sony DDS-4 Product Description Manual page 175

APPENDIX D - GLOSSARY
N-group writing
Sometimes called multiple group writing, N-group writing repeats
each group of data so that there are N consecutive copies of each group on
the tape. This is a simple way of improving data integrity, but speed and capacity are sacri-
ficed in writing all data several times.
Offline The Sony SDT-10000/SDT-11000 is offline if the tape is currently unloaded or not in the
drive. The host has limited access, and cannot perform any commands
which would cause tape motion. The host can, however, load a tape, if one is inserted, and
can execute any diagnostic tests which do not require tape motion.
Online The Sony SDT-10000/SDT-11000 is online when a tape is loaded. The host has access to all
command operations, including those which access the tape, set
configurations and run diagnostic tests.
Overlength
The incorrect length condition that exists after executing a read command when the length of
the actual block read exceeds the requested transfer length in the command descriptor block.
Only the requested amount of data is returned to the host.
Partition The entire usable region of recording and reading paths in a volume or in a portion of a
volume. If there is more than one partition, they shall be numbered starting with zero (i.e.,
beginning of partition zero).
RAW See Read-After-Write
Read-After-Write (RAW)
improves data integrity by reading data immediately after it is
written and writing the frame again if an error is found. The Audio DAT two-head drum is
replaced by a four-head drum for this purpose, the drum is
only heads and two write-only heads. Frames are only re-written as necessary, so speed and
capacity are affected minimally. RAW capability is included in the DDS format.
Reserved
Reserved for future definition and detailing and not generally available for use. Reserved bits
and fields should be set to zero.
Setmark A mark written by the host to allow fast searching to a point on the tape
without having to know the number of records or filemarks that precede this point. A
special recorded element within a partition, containing no user data, which provides a seg-
mentation scheme hierarchically superior to filemarks for use in addressing or fast position-
ing on high capacity storage devices. (Also called Save-Set Mark)
configured with two read-
SONY SDT-10000/SDT-11000 DDS Tape Drive 8 - 9