Link Driver Command and Message Queues

RSCS converts all link driver commands (for example, HOLD, FLUSH, and FWDSPACE) to command elements and places them on the command queue (LCMN) of the appropriate link driver. The LINKTABL entry of each link driver contains its command queue anchor. For non-NJE link drivers, the routing element of the CMD command is also placed in the command queue.

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Figure 1. Command and Message Element Queue to Link Drivers

     +--------+             +--------+
     | Task 1 +-----+ +---->| Driver |
     +--------+     | |     +--------+
                    | |
                 |  ˅ |  |
                 +-------+
                LCMD/LMSGQ

The figure is described in the surrounding text.

RSCS converts all nodal message records (NMRs) it receives from NJE nodes for which it must forward to other nodes into routing elements. These elements, which are in the L3 format of the CMNDAREA macro, are placed on the message queue (LMSGQ) of the appropriate link driver task. The LINKTABL entry for each link driver contains the anchor for the message queue.

If a command or message is routed to another node, the command processing and message-issuing modules also generate routing elements. These elements are placed in the link driver’s message queue.