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Coupling Facility Serviceability-Event Notification of Link-Incident Records and Error Reporting

IP.com Disclosure Number: IPCOM000115268D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30

Publishing Venue

IBM

Related People

Elko, DA: AUTHOR [+4]

Abstract

A means of providing notification and link-incident-record information for coupling facilities to support "Serviceability" is described. Event notification and commands for retrieving error (Coupling Facility Serviceability) reports are described. Link-incident record formats and reporting procedures for errors detected by the channel/coupling facility are described.

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This is the abbreviated version, containing approximately 24% of the total text.

Coupling Facility Serviceability-Event Notification of Link-Incident
Records and Error Reporting

      A means of providing notification and link-incident-record
information for coupling facilities to support "Serviceability"  is
described.  Event notification and commands for retrieving error
(Coupling Facility Serviceability) reports are described.
Link-incident record formats and reporting procedures for errors
detected by the channel/coupling facility are described.

      Event-Notification Procedure - Two storage objects are
maintained in the coupling facility for managing link-incident-record
reporting; the incident-record-pending indicator (IRPI) and the
incident-record queue (IRQ).  An instance of these reporting objects
is depicted in the following figure.

Incident-Record-Pending Indicator (IRPI):  A one-bit field that
indicates the existence of an incident record.

Incident-Record Queue (IRQ):  A set of incident records where each
record consists of a fixed-sized field, the Incident Record Header
(IRH), and a variable-sized field, the Incident Record Trailer (IRT).
The incident record header is 64 bytes and is optional for each
incident record.  The incident record trailer ranges from 0 to 4096
bytes and may contain a link-incident record.  The incident-record
trailer is also optional.  There is no prescribed order for the set
of queued incident records.

Coupling-Facility Commands - Two commands are used by the operating
system to retrieve link-incident records from the coupling facility:
  Read facility parameters
  Read and delete incident record

Read Facility Parameters: The read-facility-parameters command is
issued periodically by the operating system to retrieve
incident-record-pending indicator.  When the IRPI is zero, no records
are pending and no action is taken.  When the IRPI is one, one or
more link-incident records are available for retrieval.

Read and Delete Incident Record: The read-and-delete-incident-record
command is issued after a previous read-facility-parameters command
has observed an IRPI set to one.  The read-and-delete-incident-record
command removes the first link-incident-record from the queue, and
returns the link-incident record and a response code that indicates
the new state of the incident-record queue.  The possible response
codes are as follows:
  0  Last incident record returned
  1  More incident records pending
  2  No incident records pending

      When the response code is "0", no further action is taken.  The
incident-record queue is empty and the incident-record-pending
indicator is zero.

      When the response code is "1", the
read-and-delete-incident-record command is issued a second time.  The
command is continually issued until the response code of 1 is no
longer returned or until a threshold of service time for incident
records is exceeded.

      When the response code is "2", no incident record was returned.
The incident-record queue was em...