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Inhibiting Reset of Buffered Log During I/O Resets

IP.com Disclosure Number: IPCOM000052420D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cole, DC: AUTHOR [+3]

Abstract

All sense and status information stored in an I/O subsystem has in the past always been reset by I/O resets. A system reset, or selective reset, would previously reset any recorded information within a sub-system relative to a device or group of devices. This article teaches a subsystem that ignores RESET instructions to some accumulated sense or log data which reflects subsystem history.

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Inhibiting Reset of Buffered Log During I/O Resets

All sense and status information stored in an I/O subsystem has in the past always been reset by I/O resets. A system reset, or selective reset, would previously reset any recorded information within a sub-system relative to a device or group of devices. This article teaches a subsystem that ignores RESET instructions to some accumulated sense or log data which reflects subsystem history.

Buffered log data is sense-type information that is accumulated over long periods of time -- sometimes hours. The buffered log data is provided to the host in one of two fashions: the host may specifically read the buffered log using a Read Buffered Log channel command, or the subsystem will supply the buffered log data in place of short-term error information when certain specific conditions arise that make it desirable for the subsystem to inform the host of the long-term history of activity for a specific device. During the latter fashion of supplying buffered log data, which is the most commonly used, the control unit does not even permit the host to retrieve any information other than the buffered log. This is due to the fact that buffered log data is of such high importance to the proper tracking and maintenance of the subsystem that the control unit ensures that the host does not neglect to become aware of the information.

By rigid definition of an I/O reset, be it system reset or selective reset, it would have been appro...