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Deterministic Asynchronous QDaemon Mechanism for Distributed Print Error

IP.com Disclosure Number: IPCOM000112907D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Duvall, KE: AUTHOR [+5]

Abstract

In an IPDS datastream environment, a sophisticated mechanism is required to support multiple file per job recovery actions requiring full state information of a job object. A limited Application Program interface was replaced because it did not define the concept of a TTY (device at the qdaemon level).

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This is the abbreviated version, containing approximately 73% of the total text.

Deterministic Asynchronous QDaemon Mechanism for Distributed Print
Error

      In an IPDS datastream environment, a sophisticated mechanism is
required to support multiple file per job recovery actions requiring
full state information of a job object.  A limited Application
Program interface was replaced because it did not define the concept
of a TTY (device at the qdaemon level).

      An IPDS datastream error communications path definition
utilizing semaphores and transient process ID's through a Qdaemon
backend filter interface is defined.

      A Qdaemon intercept is defined as a backend to the Qdaemon.
The backend parameter checks the data stream, identifies it as an
IPDS datastream, resolves valid parameters and uses a spawned process
ID coupled with a semop (semaphore operation) to uniquely define the
operations to the device driver.

      If an error occurs in the IPDS distributed print environment, a
temporary pid tag is used to relate the error to an associated file
descriptor for the job.  In this way, the job information is related
to the error information.  This eliminates a problem of latency in a
distributed environment; wherein the actual error occurs on a remote
system, some time after the originating job information has been
discarded.

      A TTY mechanism does not exist at the qdaemon level, therefore
a means is defined which correlates the user name and a related
message are encapsulated in a script temporary file and a TTY se...