MPE/iX Glossary of Terms and Acronyms (32650-90887)

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Glossary of Terms
DBEFileSet A logical grouping of DBEFiles. A relation can span DBEFiles within a
DBEFileSet.
DBEnvironment (DBE) The scope of transactions and recovery for HP SQL databases.
A DBE is a collection of one or more databases.
deadlock A condition that arises when multiple processes are waiting for resources
held by other processes. A process cannot release the resources it holds
until it can acquire the resources it is waiting for, but it cannot acquire
these resources until another process releases them.
debug 1. To find and correct mistakes in a computer program.
2. Debug/XL is the debug facility supplied with MPE/iX. It provides debug
information at the machine instruction (object code) level. It can be
used to debug programs written in any Hewlett-Packard-supported
language, both in native mode and compatibility mode.
decimal code The decimal representation of an ASCII character. For example, the
character A has the ASCII binary code value 01000001 and the decimal
code value 65.
default A predefined value or condition that is assumed, and used if no other value
or condition is specified.
defined volume A member volume that is not yet physically available to a volume set,
but has its name, class assignments, and space allocation specified on the
volume set information table (VSIT) of a system master volume. See
initialized volume.
delimiter A special character used to mark the end of a string of characters.
Common delimiters are a comma (,), semicolon (;), equal sign (=), or a
Return.
delta A term used to express an incremental change. Refers to a release of the
operating system with only minor changes from the previous release.
dereferencing Dereferencing substitutes the value of a variable in place of the variable
name. See explicit dereferencing and implicit dereferencing.
descriptor A set of data structures that collectively represent the characteristics of an
open file. The data structures contain the file's attributes, identification,
access control, and accounting information, and are maintained by the file
system routines.
destructive testing A deliberate attempt to cause the system or program to fail by
including a test specifically designed for that purpose.
detail data set A data set in a database whose entries contain one or more search items
but not a key item. Entries with the same search item value are chained
together; this chain can be linked to entries in master data sets that have
matching key item values. A detail data set is equivalent to a child relation
that does not have a key item.
device See peripheral.
device adapter A device that manages communications between the computer and a