Browse Prior Art Database

Control Block Validation for Avoidance

IP.com Disclosure Number: IPCOM000099300D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 3 page(s) / 118K

Publishing Venue

IBM

Related People

Bowen, NS: AUTHOR [+2]

Abstract

This disclosure describes a new technique for systems to check the validity of control A format for control blocks is introduced that an association of a testing program as a field in control block. Changes necessary to existing programs described. A new instruction exclusively for control validation is proposed which provides further by allowing the validation process to be controlled. The emphasis of this disclosure is the detection of the error condition. The recovery is directly addressed in this disclosure. It is evident the recovery mechanism is largely dependent on the control block. Much of the current operating code has already numerous built- in recovery for a variety of circumstances. It is envisioned for the present, some of the existing recovery may be applicable to the particular situations.

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

Control Block Validation for Avoidance

       This disclosure describes a new technique for systems to
check the validity of control  A format for control blocks is
introduced that an association of a testing program as a field in
control block.  Changes necessary to existing programs described.  A
new instruction exclusively for control validation is proposed which
provides further by allowing the validation process to be controlled.
 The emphasis of this disclosure is the detection of the error
condition.  The recovery is directly addressed in this disclosure.
It is evident the recovery mechanism is largely dependent on the
control block.  Much of the current operating code has already
numerous built- in recovery for a variety of circumstances.  It is
envisioned for the present, some of the existing recovery may be
applicable to the particular situations.

      Fig. 1 shows the basic steps in checking a control block using
its data.  From a practical standpoint, it is that checking is not
performed on every access to control block, but before a section of
code actively the control block.  It is assumed that the probability
an overlay is proportional to the interval of time when is exposed.
Thus, the checking or validation of the block, indicated by the
diamond in the figure, is a few instructions prior to a section of
code the control block.  If the control block is found to valid then
the program proceeds as normal; otherwise, it to initiate recovery.
The emphasis of the sections are on methods to implement the and
techniques to insert the checking into programs.

      This disclosure does not specify the routine which the actual
validation of the control block.  We this as an unspecified function
whose input is the block and output is a condition code.  The
condition are defined only to the extent that a zero indicates the
control block has passed the test.  The implementer the liberty to
further define the non-zero-return codes. addition, this disclosure
is not specific to any one  For example, when referring to calling a
this may be a branch and link in an IBM System/370 set, and a
conditional call in a stack  Furthermore, the implementation of the
code is not specified.  It could be an actual register implicitly
addressed by branch instructions a value return in a register.

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