The TANDEM command allows the display and control of another process on your terminal.
Format
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TANDEM process |
Parameter(s)
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process |
Number of the process whose activity you want to monitor. This is also called the target process. (Your own process is the originating process.) |
Description
The TANDEM command allows the user to monitor the activity of another process, which is useful for both instructional and diagnostic purposes, as well as for controlling activity on a phantom process. You must have SYS3 privileges to use TANDEM.
When TANDEM is used to monitor a target process, all input and output of the target process is simultaneously displayed on two terminals: the one linked to the target process and the one linked to the originating process. The originating process continues to operate in TANDEM mode until it is terminated by pressing ESC followed by the X key. X must be entered in uppercase. On exiting TANDEM mode, the originating process returns to the TCL prompt.
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NOTE |
The TANDEM command cannot be stacked in a Proc or an mvBASIC program, since it accesses data one character at a time. |
TANDEM has three modes available to the user:
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View Mode |
Allows only observation of the target process’s input and output. This is the default mode, in operation when you enter TANDEM at the TCL prompt. To return to View Mode from one of the other two modes, press ESC followed by V. When you enter TANDEM at the TCL prompt, you are put in View Mode and this message displays:
All input and output generated by the target process displays on the screen of the originating process. |
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Feed Mode |
Allows input to be entered from the originating process to be used in processing by the target process. Input and output generated by the target process continue to be displayed. To enter Feed Mode, press ESC followed by F. When the TANDEM processor is in Feed Mode, input generated from the originating process is sent to the target process and used for processing. Any input and output generated by the originating process displays on both screens, as well as all input and output generated by the target process. |
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Feed Mode |
Allows input to be entered from the originating process only for display on the target process’s screen but not for processing. Input and output generated by the target process continue to be displayed. To enter Message Mode, press ESC followed by M. When the TANDEM processor is in Message Mode, input generated by the originating process displays on the target process’s screen as a message but is not used for processing. Any input and output from the originating process displays on both screens, as well as all input and output generated by the target process. |
Changing Modes
To change modes at any time, or to force the target process into the debugger, use these escape sequences:
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ESC Sequence |
Result |
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ESC D |
Forces the target process into the System Debugger. |
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ESC F |
Enters Feed Mode. |
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ESC M |
Enters Message Mode. |
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ESC V |
Enters View Mode. |
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ESC X |
Exits TANDEM mode. |
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ESC ESC |
Sends an ESC character to the target process (press ESC twice). |
To enter any of these escape sequences, first press ESC, then press the desired character key. The character must be entered in uppercase. Do not press the ESC key and the character key simultaneously.