SCHEDULE (command)

From NDWiki
Jump to: navigation, search
@SCHEDULE <device no> ... <device no>

Reserve devices to be used for a job. This command is used to reserve devices for the current batch job, thus preventing errors from occurring if trying to use the devices already reserved by other users.

<device no> 
(octal, logical device number) devices to be reserved, see [1].

The most common device numbers are

2 Paper tape reader
3 Paper tape punch
4 Card reader
5 Line printer

If one of the specified devices is reserved by other users, the batch process will enter waiting state until they are released.

To prevent deadlock situations, no device can be used by the batch job before a SCHEDULE command is given. If it is, the error message

DEVICE ALREADY RESERVED

is given, and the batch job will be aborted.

Rules:

  1. Numbers must be in ascending order.
  2. Permitted for all users. Used escpecially in batch jobs, but may also be useful for time-sharing, eg. when further operations depend on device availability.
  3. If a specified device number is reserved by another user, the calling user must wait until the device is released.
  4. To prevent deadlock, all device numbers must occur in @SCHEDULE before they are used.
  5. The devices may be released explicitly or they are automatically released on log out.

Example:

@SCHEDULE 2, 3, 4, 5

The batch job reserved logical device numbers 2 (paper tape reader), 3 (paper tape punch), 4 (card reader) and 5 (line printer).

Related commands

@RESERVE-FILE

References

Norsk Data Document ND–60.050.06 SINTRAN III USERS GUIDE section 3.7.5.2

Norsk Data Document ND–60.128.03 SINTRAN III REFERENCE MANUAL (printed February 1983), page 1-178

Norsk Data Document ND–60.174.Q01 SINTRAN III QUICK REFERENCE CARD

  1. Norsk Data Document ND–60.050.06 SINTRAN III USERS GUIDE Appendix C