Browse Prior Art Database

Ibm System/370 I/O Maintenance Control

IP.com Disclosure Number: IPCOM000036371D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 4 page(s) / 100K

Publishing Venue

IBM

Related People

Mitchell, MJ: AUTHOR

Abstract

Disclosed is a mechanism to provide system maintenance functions in a standard, architected way. Maintenance or support functions are IML (Initial Microprogram Load), manual controls such as alter-display, diagnostic program execution and procedures, error logging and reporting, and configuration control.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 4

Ibm System/370 I/O Maintenance Control

Disclosed is a mechanism to provide system maintenance functions in a standard, architected way. Maintenance or support functions are IML (Initial Microprogram Load), manual controls such as alter-display, diagnostic program execution and procedures, error logging and reporting, and configuration control.

First, the definition is at the S/370 I/O Channel Program Level; this would allow the same Channel Control Words (CCWs) to execute against the S/370 OEMI interface, Serial Optical Channel, LANs, or any other media that is controlled by S/370 I/O Channel Programs. Further, the origin and control of the Channel Programs could be the Service Processor or a S/370 Program executing in the Central Processor.

Only one simple extension to the S/370 I/O Architecture is required: One additional byte returned in response to the Sense ID command would be defined as a control unit unique "maintenance command". Existing control units would not provide this byte; new, participating units would send this parameter in response to the Sense ID. The maintenance command (MC) would then be used by the "Maintenance Manager" for any subsequent maintenance functions with that device in the following way: The MC would always be the first CCW in a chain. It would execute as a command-immediate that could receive either channel- end and device-end together or separately. The MC would always command-chain to CCWs that define the specific maintenance functions that the control unit is instructed to execute. When the control unit receives the MC, it enters a "maintenance session" with the defined device address until the completion of the Channel Program--for as many CCWs as there are in the chain. Disconnected command chaining can be used where a maintenance function requires a relatively long control unit action, and also as a way to free the channel for other normal activity. Note that the "lifetime" of a maintenance session with a device address spans the period beginning with the MC and terminates with the Interruption Condition posted as a result of the last CCW in the chain. This also provides a clean envelope of control for a maintenance operation, particularly with regard to any error conditions that might...