Table of Contents

System Software Operations Guide, Volume 2: Commands

Systems operators and programmers can direct the MCP to perform particular actions through the use of Master Control Program (MCP) system commands. These commands have many functions, including display or change of system, program, or device status and initiation and control of various system utilities. This guide lists the system commands in alphabetical order and discusses the use and syntax of each command.

System commands can be entered in the following ways:

Keyboard Input Messages Versus MCP Control Instructions

There are two types of MCP system commands: keyboard input messages and MCP control instructions. Each of the commands described in this guide specifies whether it is a keyboard input message or an MCP control instruction.

Keyboard input messages have a wide range of functions, such as inquiry and system maintenance. For the most part, keyboard input messages are 2- or 4-character abbreviations, such as DD (Delete DLP) or TR (Time Reset).

The MCP control instructions generally affect a program in the mix by either initiating a program or providing special parameters for the execution of a program. These control instructions are mostly full-word commands, such as EXECUTE (Execute Library Program) or PERFORM (Schedule DMPALL).

The precise differences in how the two are entered are as follows:

Entering Commands through the ODT

System commands are entered at the top line of the ODT, and they can continue to subsequent lines.

To enter commands through the ODT, do the following:

  1. Position the ODT cursor at the top of the screen by pressing the CLEAR/HOME key, if necessary.
  2. Type the desired command.
  3. If the ODT is a T27, B 20, ET 1100, TD 830, or MT 983 device, you can transmit the command by pressing the transmit key. All data preceding the cursor will be transmitted to the MCP. For other devices, press the End-Of-Text (ETX) key, which places an ETX character on the screen and returns the cursor to the Home position. Then press the transmit key.

Optionally, the command can be terminated with a period (.) character prior to the ETX, in which case all text following the period is ignored. When the MCP acknowledges the command, the ODT is set in receive mode.

If you have multi-line input, put an ETX character at the end of the message, put the cursor at the beginning of the message, and then press the transmit key.

Note: Pressing the transmit key causes everything from the ODT cursor to the ETX character to be sent to the MCP. It is important, therefore, that the cursor be positioned at the beginning of the message before the transmit key is pressed and that no spurious ETX characters be on the screen.

If you make an error while typing in a command, press the CLEAR/HOME key and then retype the command.

If a command is entered incorrectly, the MCP returns the following message:


MCP Response to ODT Input

The MCP responds to ODT keyboard input in the following way:

A single-line response to an input request will be displayed on the second line of the screen (the remainder of the screen will not be cleared). For a multiple-line (or no-line) response, the second line of the screen will be cleared. A multiple-line response will be displayed following the header and any skip-lines.

System commands are indented one additional space when they are displayed on the ODT “messages” screen and in the ODT log listing to make it easier to identify input requests. However, this does not affect keyboard output messages returned to a SPOMESSAGE BCT.

The system message display is indented four spaces. The lines that have not previously appeared in a display will be highlighted, independently of system message displays on any other ODT terminal. It will therefore be possible to see at a glance which messages are new.

When input messages are entered from an ODT, they appear in a DQ (Display System Messages) command response and/or from the AD MSG display. All input messages are flagged with ”=⇒” to the left of the display line.

If the command requires the MCP to display multiple lines, all available lines except the communication interface area and lines reserved by the ODT SK option are used, and lines currently being displayed are overwritten or erased. See UNIT Record and the AD (Specify ODT Screen Parameters) command for a description of the ODT SK, HDR, and MSG options.

Replies that exceed one line remain on the screen for 30 seconds or until the system operator enters an ETX (or transmits blanks) for a new screen display, an ES (End Screen - ODT Only) command to end screen display, or another input request that would cause the current display to be overwritten or erased.

If the reply to the command requires more lines than are available on the ODT screen, the MCP uses all available lines except the communication interface area lines and the lines reserved by the ODT SK option. The MCP then displays “MORE DATA” in the communication interface area. No more data is written on the screen for 30 seconds or until the system operator enters an ETX, one or more blanks, ES, or another keyboard input request. If, after 30 seconds, the system operator has not performed any of these operations, the MCP displays a new screen containing the overflow data.

Entering Commands through a Programmatic ZIP or ZIPSPO

The commands sent with the ZIP or ZIPSPO facilities are acted on exactly as if they had been entered at the ODT. The ZIP and ZIPSPO facilities are invoked by constructs in the various programming languages, which are discussed in the various language manuals.

If a program under execution contains a ZIP or ZIPSPO statement or equivalent syntax in a programming language that performs communication with the MCP, the statement must refer to a data area within the program. The information in that data area must conform to the following rules:

Note that MCPIX commands not supported by MCP/VS cannot be used in a ZIP statement.

Entering Commands through a ZIPSPO

The ZIPSPO function gives a user program the ability to pass control information to the MCP and to determine if any errors occurred during the processing. If there is an error, a response will be returned to the program.

The ZIPSPO response area is 82 characters long. The first two characters contain a numeric error code; the remainder contains the text.

If no errors are detected, the error code will contain “00” followed by a 4-character value containing the Run log number of the last job initiated by the ZIPSPO or “0000” if no jobs were initiated. The remaining 76 characters are undefined. If an error is detected, the first two characters are non-zero and the following 80 characters will be a


keyboard response terminated by ETX.

Entering Commands through a SPOMESSAGE BCT

The SPOMESSAGE BCT passes keyboard input messages to the MCP and requests that the response be returned to the requestor. The input message must be terminated by either a period (.) or an ETX character.

Note that you cannot enter MCP control instructions through a SPOMESSAGE BCT.

The length of the response buffer must be at least 80 characters and must not overlap the input area. The output buffer should be cleared before calling this BCT.

If you enter a command not valid through a SPOMESSAGE BCT, a message stating that the request is not allowed appears on the ODT.

See the V Series Program Interfaces Programming Reference Manual for more information.

Entering Commands through Punched Cards

If punched cards are used to communicate a command, the following rules apply:

Entering Commands through CANDE, PROPS, or WFL

The Command And Edit (CANDE) system is a multi-user timesharing facility that provides several levels of system and file access control.

The Programmer's Productivity System (PROPS) is an interactive program development environment.

The Work Flow Language (WFL) is a Unisys language used for constructing jobs that compile and run programs on Unisys computer systems. WFL includes variables, expressions, and flow-of-control statements that offer a range of task control capabilities.

Entering Commands through RJE

The Remote Job Entry (RJE) system is a software package that permits commands to be sent from a remote site to a central system, and that enables output of data from the central system to be sent to remote peripherals.

Entering Commands through BNA

BNA (Burroughs Network Architecture) is a software system used to link Unisys computer systems together in a data communications network. The BNA network supports full data communications, distributed processing, and virtual station transfer, as well as remote command entry.

Command Details

The following comments apply generally to all the system commands:

File Identifiers

A file identifier is the name contained in the directory for the referenced device, such as a tape, disk, or pack. A file identifier can be up to six printable characters long, but cannot be made up of all blanks or all zeros.

All library maintenance commands use an expanded method of identifying a file identifier. A file identifier can contain any combination of printable EBCDIC characters with the exception of left and right parentheses, period, comma, semicolon, hyphen, slash, and space; however, these characters (except the right parenthesis) can be used if they are enclosed in parentheses.

An equal sign not enclosed in parentheses, used in any position of a file identifier, indicates that any character is acceptable in that character position. An equal sign used in this fashion is also called a masking character.

A file identifier that contains masking characters is referred to as a file-group identifier. Trailing equal signs are assumed if the file identifier ends with an equal sign.

The following examples, as shown in Table 1-1, are specific file identifiers that would be syntactically equal to the file-group identifier.

A= A
All file identifiers starting with the letter A
A A Only the file identifier A
=A= AA
All file identifiers with an A in the second character position
All file identifiers with an A in the first character position and a F in the sixth.

An equal sign must not be separated by a blank space from the letters of a file-group identifier. A single equal sign normally causes all file identifiers to be specified. Exceptions are detailed under each applicable system command.

The file identifiers listed in Table 1-2 are reserved for use by the MCP and cannot be used for user-created disk files.

Reserved File
ADFL*W AD rule overflow file (* is a system number and can be 0 through 3)
CONFG* System Configuration File (* is a system number and can be 0 through 3)
DSKAVL Disk Available Table
DSKDIR Disk Directory
hlparm Halt/Load Parameters
MCPMCP Operating MCP Area
mstavl Master Disk Available Table
nLOG*w MCP Logs (System Option Dependent). (n denotes the type of log and can be M, R or S), (* is a system number and can be 0 through 3) (w denotes a rotating log file number and can be 0 through 9; 0 is the current log file and X is a reserved log file).
PCRXRF Pseudo Card Reader dictionary
pntp*t Program Name Table (* is a system number and can be 0 through 3)
SQARCY Disk SQUASH recovery file
USERFL System Access Control File
USRCOM System Access Control File
$*0001 MCP Memory Dump Area (* is a system number and can be 0 through 3

Special Characters

Table 1-3 lists the special characters that cannot be used in a file identifier except when enclosed in parenthesis.

Period (.) A period delimits an ODT message line or system command on one record.
Semicolon (;) A semicolon denotes another system command to immediately follow.
Comma (,) A comma delimits a file identifier
Hyphen (-) A hyphen indicates command continuation.
Equal (=) An equal sign indicates a masking (wildcard) character position.

Be careful when using file identifiers that begin with special characters that are also used by the MCP, such as the following:

  1. @ which identifies a printer backup file
  2. # which identifies a pseudo card deck
  3. * which identifies a punch backup file
  4. $ which identifies a dump file

Command Restrictions

The following restrictions apply to the various system commands:

Access Level

A terminal can be restricted to permit input of only certain types of system commands. These restrictions can be set in the LEVEL parameter of the UNIT ODT record of the system configuration file, which declares the terminals that communicate with the MCP.

Table 1-4 shows the type and access level of each command.

Note that all commands permitted to lower-level ODTs are also permitted to ODTs with higher classifications. Except for level 8 or 9 ODTs, commands requiring a <mix no> can be used only if the <mix no> refers to a program originating from the station that also originated the command.

0 1 3 5 7 8
Inquiry Job