ICL 1900 Series George 3 Operating System Commands

NEEDS

Function

Indicates to the high level scheduler the probable maximum number of online preipherals that will be required at any one time during the running of a job.

Format

NEEDS a₁,a₂,....a_n

Each parameter gives the maximum number of on-line peripherals of a particular type which the job is expected to use at the same time. The format of each parameter is

    number peripheral type(not preceded by an asterisk)

Forbidden contexts

NO USER

Execution

The NEEDS command is a system macro which makes use of the JOBDATA command. It stores the information given in its parameters in the file :SYSTEM.JOBLIST for use by the high level scheduler. When deciding which jobs to preseent to the low level scheduler, the high level scheduler takes into consideration on-line peripheral requirements of which it has been informed. In this way it can schedule jobs more efficiently and avoid jams resulting from jobs trying to use too many of the same type of peripheral at the same time.

Example

NEEDS 3LP,5MT,2CR

Notes

1. Users should give NEEDS commands before attempting to use online peripherals.
2. A NEEDS command will supercede any previous NEEDS command and may be submitted at any time.

Error Messages

z NOT RECOGNISED
PARAMETER MISSING
PARAMETER NULL