Browse Prior Art Database

System Event Indication

IP.com Disclosure Number: IPCOM000059798D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Crooks, TL: AUTHOR [+2]

Abstract

Event indicators may be described as system operation progress indicators, the purpose of which is to convey information to the system operator or customer service representative without the use of a console or work station. Event indicators -- unlike system status indicators (which indicate specific current conditions or states of affairs in a machine, i.e., parity, processor check conditions) or address/data displays -- highlight events which have or have not occurred during initialization or subsequent operation of the system. They can thus be used to trace the progress of the system during bring-up or while performing one or more sequences of operations. This information can be of extreme importance in diagnosing the cause of a system hardware or software problem.

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System Event Indication

Event indicators may be described as system operation progress indicators, the purpose of which is to convey information to the system operator or customer service representative without the use of a console or work station. Event indicators -- unlike system status indicators (which indicate specific current conditions or states of affairs in a machine, i.e., parity, processor check conditions) or address/data displays -- highlight events which have or have not occurred during initialization or subsequent operation of the system. They can thus be used to trace the progress of the system during bring-up or while performing one or more sequences of operations. This information can be of extreme importance in diagnosing the cause of a system hardware or software problem. Event indicators can also be of significant value in customer setup applications where they are used to indicate to the customer progress in bring-up of the system. In some cases, the event indicators are unique lights. In other cases, the lights are shared by other system functions (such as address or data display). Prior event indicators are either used to indicate a few very specific events (for example, "LOAD COMPLETE") or to provide very gross indications of the events occurring in a system (such as successful or unsuccessful completion of a series of diagnostic tests). Using the present system, a Machine Check Microinstruction Address Backup Register (MCMAB) is used as a dual-function register to perform the following functions: a. Provide a large number of event indication codes denoting the progress of the machine in completing specified events during system initial program load (IPL) and subsequent operation. Up to 65,536 different events or conditions can be defined. b. Provide return addresses for branch and link operations executed on the machine check-level. Control logic is provided to automatically display the MCMAB in the hex display of the operator/CE control panel whenever the Control Store Processor (CSP) stops operating while in the run mode (i.e., processor check condition or processor halt condition). Thus, the event code is automatically displayed. The MCMAB is loaded at various checkpoints during the IPL procedure with specific event codes which denote the progress made during IPL. Control logic forces display of one or more of the hex codes to indicate IPL progress prior to loading of the MCMAB with valid event information. Microcode saves and restores the contents of the MCMAB (i.e., the event indication code) if a branch and link operation must be executed on the machine check program level. Microcode instructions stop the CSP while in RUN mode so that the MCMAB is displayed. These instructions are invoked during customer setup or during regular system bring-up/operation if abnormal conditions are detected which indicate a need to stop the CSP. The codes are predefined and are loaded sequentially into the register, t...