User Guide
Ampex 1308911-02 A-9
Glossary and Acronyms Glossary
Position A location on a DD-2 tape that is speciļ¬ed by a combination of
partition, FSN, and LDBN. Some drives allow a DST600-compatible
positioning mode that uses the CDBN (cumulative data block number
within the partition) instead of the LDBN. See also current position.
Preformatting See Full Formatting.
Process The unique execution of a program. An operating system process has
a process ID, which is a unique number assigned when the program is
invoked. If the same program is run by different users or by the same
user multiple times, each execution is assigned its own process ID.
Processing Control Function (PCF)
The portion of a DST drive that performs the physical block operations
on the tape. Communicates with the RCF and TCF. On the DST310,
the PCF is implemented by the SBC board.
Recorder Control Function (RCF)
The portion of a DST drive that provides the user interface and data
buffering. Communicates with the PCF. On the DST310, the RCF is
implemented by the IBS board.
Random Access Device
A device that can position to any location on the medium using an
absolute address and that can read or write data at any position without
affecting the data at other positions. Though a DD-2 tape can position
using an absolute address, it is not a true random-access device
because writing data invalidates all previously-written data in the
partition past the point of writing.
Read A system call that transfers data over an open device interface from a
device to the calling program.
Record Another name for a logical data block.
Reset To initialize the tape drive hardware and restore all drive parameters to
their last saved values. Resetting clears any active I/O processes,
pending data, and dynamic status information. Resetting also executes
the drive power-up self tests.
Retension An operation that brings the tape to a consistent tension. DD-2 tapes
are maintained at a constant tension and do not require retensioning,
so the retension operation only sets the current position to the
beginning of the current partition.
Rewinding An operation that sets the current tape position to the beginning of the
current partition.