ICL 1900 Series George 3 Operating System Commands

MONITOR (MN)

Function

Starts or stops the monitoring of program events of specified types.

Format

1. MONITOR ON or OFF,event type
   The event type may be any one of the following:
   

   Event Type	Action if MONITOR ON is given
   DELETE	DEL or DELTY instructions are treated as if they were SUSWT or SUSTY instructions. This means that these instructions generate events of the HALTED and not the DELETED category if this type of monitoring is switched on.
   DISENAGED,peripheral name	Monitors PERI instructions for the named peripheral if the peripheral is disengaged. An error is signalled if the peripheral is not already on-line. (Note that for the purpose of this command an ONLINEd job source, for example an ONLINEd job description file or MOP terminal, is not regarded as being an on-line peripheral.) This also applies to ONLINEd command issuers.
   DISPLAY	Monitors DISP and DISTY instructions (and makes them cause a program event)

   
   
2. MONITOR ON or OFF,monitoring expression
   The monitoring expression is a list containing one or more of the categories listed below. When using more than one category, categories must be seperated by an '&' character.m
   

   Category	Action if MONITOR ON is given
   ALLOT	Monitors any ALLOT extracode on an unallocated peripheral if bit 14 of the word addressed by the operand is unset.
   CLOSE	Monitors any PERI extracode attempting to close a file or magnetic tape (including exofiles).
   CONT	Monitors any CONT extracode.
   DIS	Monitors any DIS extracode.
   EXTEND	Monitors any PERI extracode attempting to extend or contract a file or exofile.
   OPEN	Monitors any PERI extracode attempting to open a file, exofile or magnetic tape unless the device concerned has previously been ONLINEd or ASSIGNed.
   REL	Monitors any REL extracode.
   RENAME	Monitors any PERI extracode attempting to RENAME a file exofile or magnetic tape. This includes any attempt to write after rewind on magnetic tape.

If MONITOR ON is given, each category of the monitoring expression may be qualified by a list of peripheral types or peripheral names. The qualifiers must be seperated by '&' characters and the complete list enclosed in parentheses. If a qualifier is given monitoring will only occur if the peripheral type or peripheral name specified by the extracode is included in the qualifier list. Otherwise monitoring is set for the specified category on all peripherals.

If some of the monitoring categories are to have the same qualifier(s), the monitoring expression may be abbreviated by writing the categories, seperated by '&' characters, as a list, enclosed by parenthese and followed by the qualifier(s).

If MONITOR OFF is given, no qualifiers are allowed and monitoring of the specified categories is turned off for all peripherals.

Forbidden contexts

NO CORE IMAGE

Execution

After monitoring has been turned ON for any event type,occurances of that event cause a return to command level, until the monitoring is turned OFF. In the case of an illegal instruction which would have been monitored had it been legal, GEORGE may either generate a FAILED program event or monitor the instruction.

Examples

1. MONITOR ON,DELETE
   MONITOR ON,DISENGAGED,*CR0
   MONITOR OFF,DISPLAY
   
   
2. MONITOR ON,REL&DIS&OPEN
   MONITOR ON,CONT(*TR&*CR3)&OPEN(*MT1)
   MONITOR ON,RENAME&(OPEN&CLOSE)(*DA1&*DA2)
   MONITOR OFF,REL&ALLOT

Notes

1. If a category is qualified by a peripheral type for which the extracode corresponding to the category is illegal, this may not be detected as a command error.
2. The program will normally be restarted with a RESUME or MONRESUME command.

Error Messages

THE NAMED PERIPHERAL IS NOT ONLINE
z CONTAINS AN UNPAIRED DELIMITER
z IS AN INVALID COMBINATION OF MONITORING AND PERIPHERAL TYPES