Computer Diagnostics

The Computer Diagnostics arose from the same moment as the beginning of computer design. The necessity of verification of behavioural of circuits is regular process of design, and manufacturing, fault discovering on the basis of errors found by the test process is the substantial activity in circuit debugging and computer assembling, as well as in services. The testing is the practical application of diagnostics, it is necessary to fault discovering from the errors indicated as the responses of fault circuit. They are not in congruency with the description of technical specification. The increasing circuit complexity of computers causes the necessity to apply the sophisticate methods of testing. Minimisation of the length of test vector sequences, together with clever way of error detection through the test processing are the basic assumptions for effective testing, namely in these cases, if it is used pseudo-random test generation.
Application of response compression by the method of signature analysis during the test results evaluation is very carefully worked out test method, which is contained as the part of Boundary-Scan Test methodology defined by IEEE Std 1149.1. The BSDL language does the support of the circuit design. Frequently asked parts of digital systems are tests of memories, they are with respect to more complicate model of failure and with respect to regular structure of memory chip, generated by algorithmic ways. Statistic evaluation of failure occurrence and the effective capture of errors during the tests complete the overview of test methods of semiconductor memories. Specific requirements for test machine construction of memories are introduced in this coherence. The extra chapter is devoted to memory dynamic parameter testing. Briefly introduced are methods of on-line testing with the support of error-control coding of written files in memories.