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Browse Prior Art Database

Hang Protection Mechanism

IP.com Disclosure Number: IPCOM000113329D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Baier, KJ: AUTHOR [+4]

Abstract

This invention protects programs from locking up in the event that a called program does not respond to a synchronous call. A problem example:

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Hang Protection Mechanism

      This invention protects programs from locking up in the event
that a called program does not respond to a synchronous call.  A
problem example:

1.  P1 calls P2 every .24 seconds in a sequenced call.  P1 will not
    proceed until P2 responds with either an error code or with a
    success code.

2.  If P2 is in error and hangs (does not respond) during or before
    the call from P1.  Both processes are locked up.

3.  Processes that then call P1 would also become "in error".

4.  The invention also considers slow down and provides an ignore
    process to allow continuation and retry.

Hang Protection Design:

Using P1 as the process being protected and providing protection and
P2 as the process in error:

1.  Before calling P2, P1 starts a program thread that will timeout.

2.  The thread waits for a prescribed time for P2 to return control
    and then performs an acceptable continuation action.  The action
    could be one or more of:

    a.  Stop P1 to protect programs that call P1 from the hang.

    b.  Continue after the call to P2 and keep retrying depending on
        the process requirements.

3.  The continuation action is process specific and must be
    determined by each programmer.

4.  The continuation action on slow downs is also process specific
    and must be determined by each programmer.  An example of a slow
    down action for a process that needs to process events from...