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

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Glossary of Terms
data circuit terminating equipment (DCE) Equipment used to send information
between locations, such as a modem. DCE is also known as data
communications equipment.
data communications The transmission of information from one computer or terminal
to another. It is sometimes shortened to datacomm.
Datacommunications and Terminal Controller (DTC) An MPE/iX intelligent
controller, with microprocessors to handle communications with 900 Series
HP 3000 systems. Each DTC may contain connection cards allowing access
to X.25 networks, as well as connection cards allowing asynchronous
device connections.
data communications and terminal subsystem (DTS) The methodology used to
connect all asynchronous devices to a 900 series HP 3000, except for the
system console.
data dictionary A database used as a programmer's tool to store information about data.
It does not contain the data itself, but describes the type, location, usage,
and relationships of the data resources of an organization.
data endpoint The point at which the digital multiplexer interface (DMI) data channel
protocol is terminated. Data endpoints can be at the host computer or at
the PBX. Data endpoints are classified by the physical serial interface they
would present such as terminal or communication equipment. See data
circuit-terminating equipment and data terminal equipment.
data entry A task that involves entering information into a computer.
data item The smallest accessible data element in a database. A data item
corresponds to a column in relational database terminology.
data link layer Layer two of the Open Systems Interconnection (OSI) network model.
The data link layer checks for and corrects transmission errors over the
physical link.
data recovery The process of using special utilities to recover data that cannot be used
by the operating system from disks (due primarily to disk addressing
problems).
data segment table (DST) A table that identifies and provides pointer information to all
data segments, including those used by MPE and user's data stacks. On
the 900 Series HP 3000 the DST is used only in compatibility mode (CM).
data set A file used in a database. There are different types of data sets: detail,
manual master, and automatic master.
data switch A dynamic port allocator. Allows access from any terminal to any system
that is connected (see PBX).
data terminal equipment (DTE) The local node or the user terminal where
information enters into and exits from a data link or the computer itself.
DBCore/XL The common services that HP SQL uses on the MPE/iX operating system.
DBEFile The basic unit of storage used by DBCore. A DBEFile is a file on the host
operating system. DBCore stores relations in DBEFileSets.