Browse Prior Art Database

Resource Based Mutual Exclusion on the AS/400

IP.com Disclosure Number: IPCOM000109168D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 92K

Publishing Venue

IBM

Related People

Elliott, HD: AUTHOR [+3]

Abstract

Disclosed is a protocol for allocating a resource. A resource may be defined as any object. Examples of resources are: a field in a file, a record in a file, a group of records in a file, a tape device, etc.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Resource Based Mutual Exclusion on the AS/400

       Disclosed is a protocol for allocating a resource.  A
resource may be defined as any object.  Examples of resources are: a
field in a file, a record in a file, a group of records in a
file, a tape device, etc.

      With this protocol, an application may logically allocate one
record, or one hundred thousand records in a file, by performing an
external 'call' to a resource allocator program.  The resource
allocator program will determine whether the resource is available or
not.  If the resource is available, it is logically allocated.  If
the resource is not available, the calling program is notified, and
takes an appropriate action.  When the calling program is finished
using the resource, it should perform an additional external call to
the resource allocator program, to de-allocate the resource.

      This process does not rely on the operating system allocation
scheme (record locking and object allocation).  The operating system
supplies an active protection scheme where the protocol described
here is a passive protection scheme.  This means that when the
operating system performs resource allocation, all programs on the
system are notified of the allocation when the programs attempt to
access the allocated resource.  With the protocol, only programs
which are using the protocol will be notified if a resource is
logically allocated.

      To assist in understanding the usage of this concept, consider
the following scenario.
      o File-1 contains thousands of records.  The records are
divided into five groups, as specified by a group key called Key-1.
Each record contains a unique identifier as specified by Key-2.
      o Program-A performs a mass maintenance function against all of
the records in File-1 for a given group.
      o Program-B performs a maintenance and an inquiry function
against File-1.  The maintenance functio...