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Expanded Control Information Recorded in Nondestructive Memory During Coexistence of Multiple Releases of a Product

IP.com Disclosure Number: IPCOM000048073D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 3 page(s) / 47K

Publishing Venue

IBM

Related People

Pence, JW: AUTHOR

Abstract

One of the more difficult challenges of shipping a new release of a program product that shares control information on a nondestructive memory in a multihost environment relates to how to phase-in the expanded control information formats of the new release while the old release is still in use, but without major recoding in the prior release. Following are two approaches.

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Expanded Control Information Recorded in Nondestructive Memory During Coexistence of Multiple Releases of a Product

One of the more difficult challenges of shipping a new release of a program product that shares control information on a nondestructive memory in a multihost environment relates to how to phase-in the expanded control information formats of the new release while the old release is still in use, but without major recoding in the prior release. Following are two approaches.

The need for the first approach can result when a control record is so greatly expanded that the physical storage constraints will not enable a compatible expansion of the data. This first approach is applicable when the new release needs only to start with the current control information of the prior release but does not require interleaved use of the control information by the two releases. In this case, there is no change required to the prior release.

The need for the second approach can result when a control record is expanded but can be done in such a manner that all the control information used by the prior release can be retained in the same physical format, even though the new release generates the control information. The second approach enables alternate use of control information by the two releases. In this case, the change required to the prior release is one line to set a flag indicating the record format of the prior release.

The first approach consists of the following:

1. At initial startup of the new release, do

a one time mapping from the old format to

the new.

2. Record that the mapping has been done.

3. Leave the old control record alone to be

used by the old release.

4. Have each release u...