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

Types of NonStop NET/MASTER MS Environments
Environments and Command Processing
106160 Tandem Computers Incorporated 16–9
NET/MASTER MS command (if you have sufficient authority) from the OCS
command input line, including the EXEC and START commands. These commands
execute NCL procedures from OCS.
Figure 16-2 shows that the EXEC command queues NCL procedures for execution
(because only one NCL process executed by EXEC can execute at a time in a
processing environment). It shows that the START command executes an NCL
procedure independently of other NCL processes (because NCL processes executed by
the START command can execute simultaneously in an environment). The difference
between the EXEC and START commands is explained in detail in Section 8,
“Executing NCL Procedures.”
Figure 16-2. Scope of a Region
Region
OCS Window
==> NNM command
(including EXEC and
START)
Top-Level Environment 1
Primary Processing Environment
NCL process (executed with START)
NCL process (executed with EXEC)
012
NNM command
OCS Window 1 =>
Environments are created in a hierarchy. Figure 16-3 shows the full environmental
hierarchy for a real user, beginning with a region. The figure shows that every NCL
process has a dependent processing environment associated with it, and that the
hierarchy of that environment is theoretically unlimited. (There is, by default, a
maximum of 128 NCL processes that a user can execute concurrently. This is set by
the SYSPARMS NCLUMAX command.) Figure 16-3 also shows that every dependent
processing environment that is created operates within the scope of the region.
Compare Figure 16-3 with Figure 16-6, later in this section.