Posting the Event Control Blocks (ECBs)

After setting the return code in the parameter list, your security adapter should post the two event control blocks (ECBs) and return to CMS. To post the ECBs, set the following bit in each fullword ECB:

Byte 0
Bit 0: Reserved
Bit 1: Set to 1 to post
Bit 2-7: Reserved
Byte 1: Reserved
Byte 2: Reserved
Byte 3: Reserved

Do not alter any of the bits that are reserved.

If file pool server processing was interrupted by the communication from the security machine, CMS now returns control to the file pool server, which finishes what it was doing before it was interrupted. (Perhaps the server was doing work for another user when the response to your authorization request arrived.) When the server completes its work, it scans the ECB list and notices the ECBs have been posted. The posting of the ECBs tells the server the authorization request is complete, so the server dispatches the agent (user task) that was waiting for the authorization check and calls the authorization routine again.

If the server was not busy when the IUCV interrupt occurred (it was waiting for communications or for some ECB to be posted), CMS notices the ECBs are set and wakes up the file pool server. The server then dispatches the agent (user task) that was waiting for the authorization request and calls the authorization routine again.

In either case, your posting of the ECBs causes the file pool server to complete the work for the user who caused the authorization check.