Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Microprogrammed Diagnostics For I/O Attachments

IP.com Disclosure Number: IPCOM000078234D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 162K

Publishing Venue

IBM

Related People

Duggan, CJ: AUTHOR

Abstract

In a microprogram controlled computer system microprogrammed diagnostics are provided to isolate failures of I/O devices or their attachments The microprogrammed diagnostic routine resets the I/O attachment and sets it into a diagnostic mode. Diagnostic coded characters are sent to the I/O attachment which is run by microprogrammed instructions. Status information is sensed within the attachment and compared with expected results. Lack of comparison results in an error indication. Microprogrammed diagnostics are provided for an I/O keyboard attachment of Fig. 1 and a cathode-ray tube (CRT) display attachment of Fig. 2, which are part of the computer system, not shown.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 58% of the total text.

Page 1 of 3

Microprogrammed Diagnostics For I/O Attachments

In a microprogram controlled computer system microprogrammed diagnostics are provided to isolate failures of I/O devices or their attachments The microprogrammed diagnostic routine resets the I/O attachment and sets it into a diagnostic mode. Diagnostic coded characters are sent to the I/O attachment which is run by microprogrammed instructions. Status information is sensed within the attachment and compared with expected results. Lack of comparison results in an error indication. Microprogrammed diagnostics are provided for an I/O keyboard attachment of Fig. 1 and a cathode-ray tube (CRT) display attachment of Fig. 2, which are part of the computer system, not shown.

Flow diagrams for the keyboard attachment microprogrammed diagnostic routines are shown in Figs. 3, 4, and 5. After the keyboard attachment has been reset and set into the diagnostic mode, a sample or test character is loaded into keyboard data register 10 of Fig. 1. An I/O interrupt is then forced via OR circuit 15 and latch 20 and the contents of register 10 are sensed by a sense instruction. This instruction also resets the interrupt condition and register 10. The sensed data is compared with expected results and if the comparison fails, an error is indicated. The error indication signifies that the keyboard attachment failed. This error indication can be displayed to the operator via the CRT display, not shown. All characters of the keyboard can be...