OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

Glossary
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
Glossary-22
PDU store
PDU store. The database that stores messages in an X.400 system. A PDU store consists of a
data file and a log file. Each MR, MS, RS, and LO group has its own PDU store.
Physical Layer. Layer 1 in the OSI Reference Model. This layer establishes the actual
physical connection between the network and the computer equipment. Protocols at the
Physical Layer include rules for the transmission of bits across the physical medium and
rules for connectors and wiring.
Port Access Method (PAM). A Compaq communications subsystem that provides an
independent interface to allow applications access to token-ring or Ethernet local area
networks (LANs) on Himalaya S-series servers. The PAM subsystem provides a port
interface that applications can use by making file-system procedure calls. The PAM
subsystem implements, for LANs, the services of the Data Link Layer and layers below.
PAM replaces the Tandem LAN Access Method (TLAM) for G06 and later releases.
port address. For X25AM lines, the logical port number used to specify the address of the
connection to the X.25 network. For TLAM lines, the address used by TLAM to specify
the address of the connection to a LAN controller.
positive notification (PN). An EDIN that reports responsibility for an EDIM has been
accepted. A positive notification is generated by a receiving EDI-UA, EDI-MS, or
PDAU when EDIM responsibility can be given to the associated user. A positive
notification is generated only if it had been requested by the originator of the EDIM.
See also EDIM responsibility.
Presentation Layer. Layer 6 in the OSI Reference Model. This layer resolves the
differences of varying data formats between systems of different vendors. It transfers
data in a system-independent manner, performing appropriate conversions at each
system as necessary.
presentation selector. See PSEL.
primitive. See service primitive.
printing distributor. An EMS distributor process that obtains formatted text for select event
messages and distributes it to a printer or other display device, or to a file.
priority. In OSI/MHS, the order in which alternate routes are attempted. Priority values are
relative only to the other priorities for a particular MTA.
Private Management Domain. See PRMD.
PRMD (Private Management Domain). An X.400 domain managed by a private
organization, such as a corporation. See also domain.
probe. An X.400 communication sent by an originator into the MTS to test the likelihood of
delivery of a message or report. It consists of an envelope and the description of the
actual content of the message or report. The envelope is similar to, but not the same as,
an envelope that would be used for an actual message or report.