International Business Machines Corporation

Raymond C Williams

John G Stevenson

Ronald D Martin

Curtis J Frantz

Rodney A Bell

Barbara Ann Smith

Marshall E Sprague

James B Staton, Iii

William V Evans, Jr

Petre N Turcu

Christopher P Ballard

Charles Henry Gaudette

John D Hajian

William G Kreps, Iii

A communication link manager for problem determination and recovery of a failing resource on a communication link segment in a data communication network. When a problem occurs on a link segment, the using node passes link event data to the communication link manager for analysis. The communication link manager interacts with a configuration data base to determine the physical configuration of the failing link segment and the controlling link connection subsystem manager. The communication link manager directs the appropriate link connection subsystem manager to initiate tests of the various link connection components on the link segment under its control. When the failing resource is identified, the communication link manager initiates the appropriate non-disruptive recovery procedure through the link connection subsystem manager and prompts the data link control to restart the line.

Method and apparatus for communication link management

Data communications neworks may be composed of many different physical devices linked together in various layers and using various protocols for communication. The multiple physical elements that make up such communication networks or links are often supplied by diverse vendors. As a result, isolation and diagnosis of communication failures becomes an extremely difficult and cumbersome process. The present system and method simplify the process greatly by premitting a system control operator or control application program to issue generic, non-device-specific problem isolation, control or diagnostic commands to the communication neetwork by identifying the link and target node for which problem isolation and diagnosis is required. The non-device-specific commands are received first at an intermediate translation facility which retrieves communication link physical configuration data and identifies the physical components and characteristics thereof that make up that communication link to the identified target node. The translation facility then issues one or more device-specific problem determination commands on the communication link directed toward said node. It receives one or more device-specific responses from one or more physcial devices in the communication link and, responsive thereto, either issues further device-specific commands on the communication link to complete the diagnosis or issues generic, non-device-specific problem identification results as responses to the requesting control nodes' initial request.

Method and apparatus for diagnosing problems in data communication

The embodiment provides a bit position in a system control register (CR) which is set to enable, and is reset to disable, the HCA protect means. An AND gate has an input which receives the enablement or disablement signal from the control register HCA protect bit position. The AND gate also receives the store requests from the processor, and further receives a signal common to all addresses in the HCA area such as all zeros for address bits 8 through 22 to signal the first 512 bytes in main storage which in current IBM S/370 machines contains the HCA, which is also called the program save area (PSA). The AND gate is normally disabled by the CR bit and provides an inverted output to a store request gate which normally provides store requests to the processor store access controls. Writing into the HCA is only permitted under special programmed conditions when the control register bit is set to disable the HCA protect means. Whenever the HCA protection is enabled, the AND gate is enabled to provide an HCA store violation signal, which actuates a protection interrupt code generator to generate a storage protect interrupt code in the PSW (Program Status Word) that causes the processor to test each store request into the HCA. The CR protect bit is disabled before and enabled after each legitimate HCA change code in a system control program to form a window in the code.

Hardware control storage area protection method and means

Growing community of inventors

Raleigh, NC, United States of America

Raymond C Williams