Processing and Executing eMS Files As shown in Part 1 of Figure 9, the five general topics form the
category "Process and Execute CMS Files." Two of these topics are
discussed in this section: "Maintaining an Interactive Console
Environment" and "Loading and Executing TEXT files."
Maintaining an Interactive Console Environment Two levels of information are discussed in the following section. The
first level is a general discussion of how CMS maintains an interactive
console environment. The second level is a more detailed discussion of the methods of operation mainly responsible for this function. Console Management and Command Handling in CMS There are two major functions concerned with maintaining an interactive terminal environment for CftS: console management and command processing.
The CMS module that manages the virtual machine console is DftSINT. The
module responsible for command frocessing is DftSITS. ftany CftS modules
are called in support of these two functions but the modules in the
following list are primarily responsible for sUPForting the functions: DftSCRD ---aeads a line from the console. !H!SC!!! Writes a line to the console. converts a command line to PLIST format. Converts abbreviated commands to their full names. Passes a command line to CP for execution.
Maintaining an Interactive Command/Response
Session
Three main lines of control maintain the continuity for an interactive CMS session: (1) handling of commands passed to DftSINT by the
initialization module, DftSINS (2) handling of commands entered at the
console during a session, and (3) handling of co.mands entered as subset
commands. The following lists show the main logic paths for first two
functions.
2-62 IBM VM/370 System Logic and program Determination--Volume 2

EXECUTE COMMANDS PASSED VIA DMSINS On entry from DMSINA, processes any commands passed via the console
read put on the user's console by that routine; that is processes
any commands the user stacks on the line as the first read that DMSINT processes. In handling the first read, if that read is null,
control passes to the main loop of the program, which is described
in the following section. Get the current time. to the waitread subroutine to read a command line at the
console. DftSSCN ---Waitread then calls to convert the line just read into plist
format. Once converted to plist format, an SVC 202 is issued (at
label INIT1A) to execute the function. This cycle is repeated qntil all stacked commands are executed. ---When command execution completes, calls DeSFNS (at label UPDIT) to
close any files that .ay have remained open during the command processing. DMSVSR that any fields set by VSAM processing are reset for ces. Also ensures that the VSAM discontiguous shared segment is purged. Sets up an appropriate status message (CMS, CftS SUBSET, CMS/DOS, etc.). Writes the status message to the console.
HANDLE COMftANDS ENTERED DURING A CMS TERftINAL SESSION Branches (from label INLOOP2) to the waitread subroutine to read a
line entered at the console. ---aeads a line entered at the console (subroutine waitread). Converts the command line to PLIST format (subroutine waitread). Determines whether the command line is a null line or a comment. DMSLFS the command line is neither a co •• and line nor a co •• eDt, determines whether the command is an EXEC file. Determines whether the command is an abbreviation and, if it is,
returns its full name. CMS Method of Operation and Program Organization 2-63