Browse Prior Art Database

Test Method for Priority Circuit of Data Processing System

IP.com Disclosure Number: IPCOM000044830D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

McMurdy, RK: AUTHOR

Abstract

A test is provided for a system in which several components use a system resource one at a time in assigned order of priority. For the test for a general number of components designated n, each component is assigned a distinctive code and each is simultaneously ordered to access the resource and to store its code in n-1 positions in a pattern that assigns two devices to write in each storage location. A location contains only the last code that was written and the contents of all storage locations indicate the order in which the components were granted priority. There are at least n(n-1)/2 storage locations to handle all combinations of two components.

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Test Method for Priority Circuit of Data Processing System

A test is provided for a system in which several components use a system resource one at a time in assigned order of priority. For the test for a general number of components designated n, each component is assigned a distinctive code and each is simultaneously ordered to access the resource and to store its code in n-1 positions in a pattern that assigns two devices to write in each storage location. A location contains only the last code that was written and the contents of all storage locations indicate the order in which the components were granted priority. There are at least n(n-1)/2 storage locations to handle all combinations of two components.

For example, four devices can share a device adapter. When a request for access to the adapter is made by more than one device at one time, access is granted to the device with the highest priority. To test the priority apparatus, eight storage locations can be used. Each device is ordered to write a unique code into three storage locations (n-1=3). Each location has one original entry and one writeover. The code in a location at the end of the test identifies the device that executed the order last, and the actual order or access can be found from the locations of the stored codes and this order is compared with the assigned priority order.

Disclosed anonymously

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