MODES OF OPERATION WITHIN MTS MTS Command Mode

MTS command mode is the default mode of system operation for all batch jobs and terminal sessions. MTS commands can be subdivided into several groups according to the services they provide. The major groups are:

(1) Global Control

The global-control commands include SIGNON and SIGNOFF to initiate and terminate jobs, and SET to set various system options.

(2) Program Control

Program-control commands include RUN, RESTART, and RERUN to initiate and/or resume program execution, and IF to test program execution results.

(3) Debugging

The debugging commands include DEBUG and SDS to enter the Symbolic Debugging System, DUMP, DISPLAY, and ALTER to inspect and/or modify registers and storage locations.

(4) File and Device Management

File and device management is provided by the CREATE, DESTROY, EMPTY, PERMIT, RENAME, RENUMBER, LOCK, UNLOCK, and CONTROL commands. Information about the status of files may be retrieved using FILESTATUS, FILEMENU, and LOCKSTATUS. The COPY, DUPLICATE, FTP, and LIST commands are useful in the transfer of data from one file or device to another. SOURCE and SINK control the current input and output streams. Magnetic tapes may be mounted by the MOUNT command.

(5) Help Information

Help information is provided by the HELP command.

The commands mentioned above are a subset of the system command language; a complete list of MTS commands, parameters that are allowed (or required) for their use, and a description of their use is given in the section “MTS Command Mode” in this volume.

Execution Mode

Execution mode is used to execute programs and is entered via the RUN, RERUN, START, RESTART, and several other commands and from debug mode as described below. If the RUN command is given, any currently loaded program is unloaded and the object module specified by the first command parameter is loaded; when loading is complete, control is passed to the loaded program at its entry point and the system enters execution mode. The RERUN command causes theprevious RUN or RERUN command to be processed as though it had just been reentered. If parameters such as logical I/O assignments are entered on a RERUN command, they override those specified on the previous RUN or RERUN. When a program is already loaded (e.g., via LOAD), the START or RESTART commands may be used to enter execution mode. Normally, the return to the mode from which execution mode was invoked occurs when the program proceeds to completion (or calls one of the system subroutines SYSTEM, MTS, MTSCMD, or ERROR).

The occurrence of certain abnormal conditions also causes a return to MTS command mode or debug mode. For example:

(1) For batch jobs only:

(a) a global time, page, or card limit is exceeded (does not return to debug mode).

(2) For batch jobs and terminal sessions:

(a) a local time, page, or card limit is exceeded.

(b) an abnormal condition (e.g., a program interrupt) occurs. The program may call the appropriate subroutine (e.g., PGNTTRP) to intercept the return to MTS command mode.

(3) For terminal sessions only:

(a) an attention interrupt occurs. The program may call the appropriate subroutine (e.g., ATTNTRP) to intercept the return to MTS command mode.

(b) the user’s account has run out of funds and the user chooses to return to MTS command mode when prompted.

Accounting Mode

Accounting mode may be used to obtain information about the resource status of a userID. It also may be used by project directors or instructors to manage the resources (money, disk space, etc.) available to their projects or classes. Accounting mode is entered via the ACCOUNTING command.

Accounting mode is described in the section “Accounting” inMTS Volume 5: System Services, Reference R1005.

Calc Mode

Calc (or desk-calculator) mode provides sophisticated desk-calculator capabilities. Calc mode is entered via the CALC command. While in calc mode, mathematical expressions may be evaluated, and symbolic variables may be defined and values may be assigned to them. Calc mode is described in the section “MTS Command Mode” in this volume. The facilities of calc mode are available to a user program by calling the CALC subroutine (see MTS Volume 3: System Subroutine Descriptions, Reference R1003).

Debug Mode

Debug mode is entered via the DEBUG or SDS command. In debug mode, a part of the system, called the Symbolic Debugging System (or SDS), enables the user to monitor the execution of a program.

The debug command language subsystem provides convenient facilities for controlling the execution of the program and for displaying and modifying instructions and/or data at any point during execution of the program. When a DEBUG command is entered, the program to be debugged is loaded for execution and appropriate symbol table information (from SYM records in the object module) is made available to the symbolic debugging system. After loading is completed, the system enters debug mode at which time the user may initiate execution of the program. While the system is in debug mode, the program may be interrupted and various locations may be displayed or modified. After any desired modifications have been made, execution of the program may be resumed via the CONTINUE, GOTO, or STEP debug commands. The Symbolic Debugging System is described inMTS Volume 13:

The Symbolic Debugging System, Reference R1013.

Edit Mode

Edit mode is entered via the EDIT command. In edit mode, the user may use the MTS File Editor to display and selectively modify the contents of a file. The File Editor provides special support for

display terminals such as the Ontel and the IBM 3270, and various microcomputers such as the IBM PC and the Apple Macintosh to visually display and modify a file. The File Editor is described inMTS Volume 18: The MTS File Editor, Reference R1018. The facilities of the File Editor are available to a user program by calling the EDIT subroutine (see MTS Volume 3: System Subroutine Descriptions, Reference R1003).

File Transfer Mode

File-transfer mode is entered via the FTP command. In file-transfer mode, the user may transfer files to or from a remote host machine. The FTP command is described in the section “MTS Command Mode” in this volume.

List Mode

List mode is entered via the LIST command. In list mode, the user may issue various commands to control the formatting of the listing. The LIST command is described in the section “MTS Command Mode” in this volume.

Message-System Mode

Message-system mode is entered via the MESSAGE or FSMESSAGE command. In message-system mode, the user may send messages to other users either local or remote. The messages may be addressed by either userID or name. The MTS Message System is described inMTS Volume 23: Messaging and Conferencing in MTS, Reference R1023.

Network Mode

Network mode is entered via the NET command. In network mode, a part of the system, called the network interface, provides access to computers located at other installations (hosts) of the UMnet/Michnet Computer Network. The NET command is described in the section “The NET Command” inMTS Volume 4: Terminals and Networks in MTS, Reference R1004.

Systemstatus Mode

Systemstatus mode is entered via the SYSTEMSTATUS command. In systemstatus mode, the user may inquire about the status of particular jobs being processed by the system, about the status of particular devices attached to the system, etc. The SYSTEMSTATUS command is described in the section “MTS Command Mode” in this volume.

View Mode

View mode is entered via the VIEW command. In view mode, the user may look at the results of a print or batch job. The VIEW command is described in the section “MTS Command Mode” in this volume.