TS/MP Pathsend and Server Programming Manual (H06.05+, J06.03+)

database
consistency
The state of a database in which items satisfy established criteria. For example, an account
balance must equal credits to the balance minus debits to the balance. When the database
satisfies these criteria, the database is considered to be consistent. In general, a database is
consistent when it is accurate and all changes generated by transactions are complete. Database
consistency is defined by the application, which establishes the values and relationships of
database fields and records.
database
management
system (DBMS)
A product, such as NonStop SQL/MP or Enscribe, that serves as the interface between a user or
program (for example, a Pathway server) and the database. Among its many functions, the DBMS
controls access to and organization of data within the database.
DBCS See double-byte character set (DBCS).
DDL See Data Definition Language (DDL).
deadlock A situation in which two processes cannot proceed because each is waiting for a reply from
the other.
1.
2. A situation in which two transactions cannot proceed because each is waiting for the other
to release a lock.
dedicated device A term formerly used for a terminal or other input/output device controlled by a configured TERM
object, so that a Pathway application always ran on that device without having to be started
from PATHCOM with a RUN PROGRAM command. (No new term replaces this term; instead,
the manual text now refers to such devices as those associated with configured TERM objects.)
See also nondedicated device and configured TERM object.
default value The value that the system uses for a particular attribute or parameter when a value has not been
supplied by the user.
DEFINE A named set of attributes and associated values. In a DEFINE (as with an ASSIGN command),
users can specify information to be communicated to processes they start.
definition files A set of files containing data declarations for items related to SPI messages and their processing.
The core definitions required to use SPI are provided in a DDL file and in several language-specific
definition files, one for each programming language that supports SPI. The HP DDL compiler
generates the language-specific files from the DDL file. Subsystems that support SPI provide
additional definition files containing subsystem-specific definitions.
delimiters Characters that make it possible for a SCREEN COBOL requester and an external device or
front-end process to exchange compact variable-length messages efficiently; delimiters can be
message delimiters or field delimiters.
descriptor For each elementary data item, the SCREEN COBOL compiler builds a data structure that describes
the size, type, usage, and dependencies of the item. All the information that pertains to a given
item makes up the descriptor for that item. For example, the PICTURE specification is included in
the descriptor. The descriptors are passed to the TCP in the pseudocode and provide a dictionary
of information for interpreting and handling incoming data. When the MAP or SMAP compiler
option is used, the descriptors appear in the compiler map at the end of the listing.
diagnostic screen A screen of information that is displayed to inform the terminal operator of error conditions and
termination status.
dialog A multiple-message communication between a requester and a context-sensitive server. A dialog
is also called a conversation. See also context sensitivity and contextsensitive server.
disk process In the NonStop Kernel operating environment, the portion of the operatingsystem software that
performs read, write, and lock operations on disk volumes and creates TMF audit records. See
also file system.
display attribute A terminal display feature that is given a screen data name. The screen data name can be
associated with a predefined system name in the SPECIAL-NAMES paragraph and therefore be
manipulated by a SCREEN COBOL program.
distributed data Information (for example, customer names and addresses, inventory items, and personnel records)
that resides on more than one node in a network and can be accessed by authorized users from
any node in that network.
distributed
processing
A type of processing environment in which resources are distributed among CPUs within a single
system or spread across a network of systems. A user on any network node can, if properly
authorized, access resources and database files anywhere within the network.
200 Glossary