GB1238162A - - Google Patents

Abstract

1,238,162. Data processing. INTERNATIONAL BUSINESS MACHINES CORP. 26 March, 1969, No. 15819/69. Heading G4A. In a data processing system, a data handling unit detects and counts errors in data handled thereby, the count being made available elsewhere in the system in response to a request signal. In a sytem with two processor units and two storage units, which is a modification of that of Specification 1,238,161, which is referred to, either processor unit can supply configuration data to the units to configure them into one or more subsystems, each unit then responding to signals from within the same subsystem only. On detection of an error, the error is corrected if possible, using an error-correcting code in a storage unit, and by instruction retry (up to a predetermined number), as in Specification 1,168,414, which is referred to, in a processor unit. Each unit counts its detected errors (including unsuccessful retries). If correction is not achieved as above, the processors are notified. The processors are also notified if correction is achieved, either every time (error counter non- zero) or when the error count is 16, according to two mode bits from the configuration data. The processor (assuming only one is configured to respond to the notification) interrupts its programme and reconfigures the system in response to the first sort of notification, e.g. to exclude the faulty unit. In response to the second sort of notification it interrupts its programme and requests stored error data (location of error, and optionally the error count) from the notifying unit and may respond to it by reconfiguring, or by changing the error-notification mode bits, or by continuing without change.