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Establishing a Recovery Environment

IP.com Disclosure Number: IPCOM000078727D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Butler, RB: AUTHOR [+2]

Abstract

This programming technique allows for the creation of a recovery environment by any program, regardless of its operating conditions (interruptible /noninterruptible, problem-mode/supervisor mode, etc.), in a manner which minimizes the number of instructions executed by the mainline paths of the program. It provides error protection to every dispatchable element of an operating system in an optimum manner. The following terms are used: 1. The Recovery Environment: The recovery environment consists of: A) A recovery routine to protect a particular path through a program. Should an error occur in the path, the recovery routine should get control. B) A parameter which gives a mainline path and ability to provide data for the recovery routine.

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Establishing a Recovery Environment

This programming technique allows for the creation of a recovery environment by any program, regardless of its operating conditions (interruptible /noninterruptible, problem-mode/supervisor mode, etc.), in a manner which minimizes the number of instructions executed by the mainline paths of the program. It provides error protection to every dispatchable element of an operating system in an optimum manner.

The following terms are used:
1. The Recovery Environment: The recovery environment consists

of:
A) A recovery routine to protect a particular path through a

program. Should an error occur in the path, the recovery

routine should get control.
B) A parameter which gives a mainline path and ability to

provide data for the recovery routine.
C) A means for the control program to associate a recovery

routine with a failing mainline path, so that control can

be passed to the recovery routine.
2. The Recovery Data Area - RDA - Space to contain the control

blocks necessary to define a Recovery Environment.
3. Operating Environment - programming elements over which the

system guarantees exclusive ownership - e.g., a program is

guaranteed exclusive ownership of the 16 general-purpose

registers while its instructions are executing. It is the

responsibility of the Supervisor Control routines to save

and restore the operating environment.
4. Supervisor Control Routines - Those supervisory programs which

gain control as the result of an interrupt, save the operating

Environment for the interrupted program, and restore the

operating Environment when the program is reinstated.

In general, the technique described herein involves making a program's Recovery Environment an integral part of its Opera...