Command Functions

All input Stations are able to obtain Command mode at any time, without interference to the program currently running (which resumes at the point of interrupt upon completion of, or escape from, Command mode). Command mode is indicated by the prompt COMMAND? and is obtained by pressing the appropriate key (CLEAR for VDU’s TAB for keyboards). Command requests are keyed-in in the usual manner and will be processed when the ACCEPT key is pressed. Several commands may be combined in a single input; they will be executed from left to right.

nThe check digit corresponding to the number n will be displayed.
QQueue List. The numbers of all non-empty Print Queues (if any) will be displayed. Further, the state of each printer program will be displayed in the format a = n pppp where a is the printer identifier (A, B ..), n is the print queue number assigned to the printer and pppp is the program name currently running (or the word IDLE).
Dd m ySet System DATE. d, m and y are numeric and separated by a single space. (Also inhibits Programming Utilities.)
UnUSE Plain Paper Q n. Printouts requested by the issuing Station will be posted to queue n where 0 <= n <= (max. plain paper queue). This command does not affect other Stations, and does not affect the program currently running at the issuing Station. (On Bootstrapping the system, all stations will revert to U0.)
KnControl Printer n. Printer Control Commands issued by a Station are applied to the printer that the Station controls (if any). This printer is determined (where there is more than one printer) on bootstrapping the system, but the Kn command allows the controlled printer to be varied. Any subsequent printer control commands from the issuing station will be applied to printer n where n = 1, 2 .. according as printer A, B .. respectively is to be controlled.
LOS Bulletin No 16 (May 1978) replaced the Kn command with the rule:
Whenever COMMAND mode is entered, printer control commands will always be directed to the issuing station’s normal printer unless the operator specifies otherwise by prefixing the command string with the required printer’s identification letter (A, B, etc.). Example: BP1 switches printer B onto queue 1.
FnFile Table n. For those installations where up to four systems may be on-line simultaneously, this command identifies the system required at the issuing Station.

Postings from different systems may be freely mixed in all print queues ( printer programs switch systems automatically).

 [The following commands provide printer control functions]
PnPRINT. n is the number of the queue to be processed. If the printer program is currently processing work in another queue it will switch queues only after completing its current posting.

P0 may be specified, e.g. if it is desired that the program remain idle whilst changing paper.

SSUSPEND/SINGLE SHOT. The printer program will despatch one further line to the printer (the command remains pending until this occurs, unless overriden by an R command).

The message PRINTER x SUSPENDED will be flashed when the line has been despatched, and the printer program awaits a further command: S, R or K.

RRUN. The printer program reverts to normal operation (suspended printout restarts).
RnRUN (restricted). The printer program will despatch n further lines to the printer. The message PRINTER x SUSPENDED will be flashed when the nth line has been despatched, and the printer program awaits a further command.
KCANCEL. If this command is accepted (i.e. does not result in ERROR) the current printer program is cancelled and the next posting (if any) in the print queue is immediately begun.
  • The print program must be Suspended before it may be cancelled.
  • Certain programs may disallow operator cancellation.