FREMGANGSMAATE OG APPARAT FOR BEHANDLING AV INFORMASJON OG FOR FEILLOKALISERING I ET PRINSIPALT APPARAT

摘要

A data processing system having a principal apparatus, such as a programmable large-scale data processing system, and a secondary apparatus. The secondary apparatus performs fault detection and analysis on the principal apparatus. The secondary apparatus under control of a secondary program and independently from the principal apparatus, accesses information from different points, such as latch circuits, throughout the principal appartus. The accessed information is utilized by the secondary apparatus to form an actual checksum having a value determined by the accessed information. The actual checksum thus formed is compared with an expected checksum provided from storage by the secondary apparatus. If the actual and expected checksums are different, a fault condition is indicated. An analysis of selected subsets of points in the primary apparatus is made using a compacted scan composed of the values of the selected subset of points.