GDSX Manual

Design and Development

Extended General Device Support (GDSX) Manual–134303

2-85

I/O for Files Other Than $RECEIVE

Two tables are used by the GDSX I/O procedures: the IOCB table and the FCB table.

TSCODE allocates an IOCB to manage each outstanding nowait I/O. Among the entries

in the IOCB are the following:

iocb.tcblink[0:1] Two-way linked list pointers for list of IOCBs for a given task.

Also used to link available IOCBs.

iocb.fcblink[0:1] Two-way linked list pointers for list of IOCBs for a given file.

iocb.lhlink[0:1] Two-way linked list pointers for use by LINE^HANDLER

tasks.

iocb.wakeup=lhlink For signaltimeout, IOCB contains the GDSX internal time

when the signal is to pop.

iocb.syncid=lhlink For $RECEIVE requests, contains the sync ID returned from

RECEIVEINFO (or FILE_GETRECEIVEINFO_).

iocb.state State of IOCB:

0 - Available: IOCB currently unused

1 - Queued: I/O is currently in process

2 - ITC-Queued: ITC IOCB that has not yet been

LISTENed

3 - Signal: ^SIGNALTIMEOUT IOCB

4 - N.A.

5 - Pending: I/O complete but not passed back to task

6 - ITC active: Task is processing the request

7 - Canceled: Task has not yet processed cancel event

8 - Receive: $RECEIVE request queued for task

9 - Reply: $RECEIVE request passed to task