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CPU Diagnostics Using Microprogram Routines

IP.com Disclosure Number: IPCOM000095748D
Original Publication Date: 1964-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Tickner, EJ: AUTHOR [+2]

Abstract

In a microprogram controlled machine, faults can be diagnosed by using a number of control words stored in a read-only memory. These words contain test data and diagnostic routine microprogram control data. They can be addressed by the main program or by push button control from the operator's console. To initiate a diagnostic routine, the first control word in the routine is addressed and test data obtained from it is transferred through selected paths in the machine. Such is under control of the other control words in the routine which are successively addressed. The test data is compared at its destination with an expected result to determine whether or not the components in the selected paths have operated correctly.

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CPU Diagnostics Using Microprogram Routines

In a microprogram controlled machine, faults can be diagnosed by using a number of control words stored in a read-only memory. These words contain test data and diagnostic routine microprogram control data. They can be addressed by the main program or by push button control from the operator's console. To initiate a diagnostic routine, the first control word in the routine is addressed and test data obtained from it is transferred through selected paths in the machine. Such is under control of the other control words in the routine which are successively addressed. The test data is compared at its destination with an expected result to determine whether or not the components in the selected paths have operated correctly.

The drawing shows a typical routine for testing a main store in which a store address and test data are generated by the read-only store. The test data is written into, and then read from, the main store. The data read out is then compared with original test data which was retained in an expected result register. One of two further routines are selected in accordance with a correct or incorrect output from the comparator.

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