NET/MASTER Network Control Language (NCL) Programmer's Guide

Operations Available Through NCL
Introduction to NCL
1–4 106160 Tandem Computers Incorporated
Automating Operations NCL contains constructs that allow NCL processes to make logical decisions based on
the analysis of system and network information. This feature of NCL, coupled with
the ability of an NCL process to monitor and control system and network activity and
to react automatically to events, allows you to automate many NonStop
NET/MASTER MS operations.
For example, an NCL process can monitor the status of terminals. A typical example
of an event to which an NCL process can react automatically is the failure of a
Pathway terminal or terminal control process (TCP). If an NCL process receives an
unsolicited message that a Pathway terminal or TCP has failed, it can attempt to restart
the terminal or TCP automatically. If the restart attempt fails, the NCL process can
wait for results and take further action.
Communicating With
NonStop NET/MASTER MS
Users and Terminals
An NCL process can communicate with NonStop NET/MASTER MS users and
terminals. It can display a message at a terminal to solicit information and resume
processing based on the input it receives.
A message soliciting information may be as simple as a message displayed in the OCS
message display area or text inserted in the OCS command input line. Input can be as
simple as a NonStop NET/MASTER MS command to the NCL process to resume
processing or to abort.
Alternatively, an NCL process can communicate with NonStop NET/MASTER MS
users by using the more sophisticated method of displaying interactive panels.
Communicating With Other
NCL Processes
An NCL process can communicate with other NCL processes. This means groups of
NCL processes can operate cooperatively to perform different tasks. They can take
instructions from, and report results to, a central controlling NCL process. The
controlling NCL process can communicate in turn with an OCS operator to report the
results.
You can also send data to an NCL process from the OCS command input line.
Communicating With
Pathway Server Classes
An NCL process can act as a PATHSEND requester to communicate with existing
Pathway server classes. It can send a request message to the server class and receive a
reply message from the server class.
A server process typically controls access to a database. A requester process typically
makes requests of a server process, for example, to add, update, or delete records in a
database. Using an NCL process to act as a PATHSEND requester, in addition to an
existing requester written in another language, offers you increased flexibility in
communicating with a server process. You can use either or both requesters to
communicate with the same server process.
Being able to gain access to an existing database from NonStop NET/MASTER MS
through an existing server process also means that you can do more while preserving
your original investment in developing the server program.