SNAX/APC Management Programming Manual

Glossary
111813 Tandem Computers Incorporated Glossary–7
PATHMON environment . The servers, server classes, TCPs, terminals, SCREEN COBOL
programs, and tell messages that run together under the control of one PATHMON
process.
Pathway. A group of software tools for developing and monitoring OLTP (on-line
transaction processing) applications that use the requester/server model. Requesters
can be either SCREEN COBOL programs interpreted by the terminal control process
(TCP) or C, C++, COBOL85, Pascal, or TAL programs that use Pathsend procedure
calls. Servers are grouped into server classes to perform the requested processing. On
Himalaya systems, this group of tools is packaged as two separate products: NonStop
TS/MP and the optional Pathway/TS. On earlier Tandem systems, the tools are
packaged as a single product called Pathway. .
physical unit (PU). That part of a device (hardware or software) that provides control
functions for its own node and for the other less intelligent device nodes attached to
that node.
PLU. See primary logical unit.
primary logical unit (PLU). The logical unit that controls a LU–LU session. Within each
LU–LU session, one of the LUs is the primary and the other is the secondary. The
most important control that the PLU exerts is the formatting and sending of the BIND
request that initiates the session.
primary process. The currently operating process of a process pair on a Tandem
NonStop system. See backup process.
process. A unique execution of a program. The operating system is a collection of
processes cooperating by using a common message system. A process is created by
taking a program from a file on disk and running it in a processor.
process pair. Two processes: a primary process that is active, and a secondary, backup
process in another CPU that is ready to take over if the primary process fails.
protocol. The set of rules governing the operation of communicating entities.
PU. See physical unit.
RC. See return code.
RCB. See resource control block.
remote TP. The transaction program with which a local transaction program
communicates.
request/response (RH) header. In SNA, control information, preceding a
request/response unit (RU), that specifies the type of RU and contains control
information associated with that RU.
request/response unit (RU). In SNA, a generic term for a request unit or a response unit.
request unit. In SNA, a message unit that contains control information such as a request
code, or function management headers, end-user data or both.