User`s guide

When the CCP gains control after a system warm start, it removes any RSXs in
memory that have the Remove flag set to OFFH. All other RSXs remain active in
memory. Setting an RSX's Remove flag to OFFH indicates that the RSX is not active
and it can be removed. Note that if an RSX marked for removal is not the lowest active
RSX in memory, it still occupies memory after removal. Although the removed RSX
cannot be executed, its space is returned to the TPA only when all the lower RSXs are
removed.
There 'is one special case where the CCP does not remove an RSX with the Remove
flag set to OFFH following warm start. This case occurs on warm starts following the
load of an empty file with attached RSXS. This exception allows an RSX with the
Remove flag set to be loaded into i-nemory before a transient program. The transient
program can then access the RSX during execution. After the transient program
terminates, however, the CCP removes the RSX from the system environment.
As an example of RSX operation, here is a description of the operation of the GET
utility. The GET.COM command file has an attached RSX. The LOADER moves
this RSX to the top of the TPA when it loads the GET.COM command file. The
GET utility performs necessary initializations which include opening the ASCII file
specified in the GET command line. It also makes a BDOS Function 60 call to
initialize the GET.RSX. At this point, the GET utility terminates. Subsequently, the
GET.RSX intercepts all console input calls and returns characters from the file speci-
fied in the GET command line. It continues this action until it reads end-of-file. At
this point, it sets its Remove flag in the RSX prefix, and stops intercepting console
input. On the following warm boot, the CCP removes the RSX from memory.
1.6.5 SUBMIT Operation
A SUBMIT command line has the following syntax:
SUBMIT <filespec> <parameters>
If the CCP identifies a command as a submit file, it automatically inserts the SUBMIT
keyword into the command line as described in Section 1.6.2.
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1.6 System Operation CP/M 3 Programmer's Guide