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Controlling the Duration of Multiple Events

IP.com Disclosure Number: IPCOM000073691D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Fauconnier, P: AUTHOR [+2]

Abstract

It is often necessary in a program to ensure that a given operation does not exceed a specified duration. (Sector seek operation on a disk, for example. In some applications like process control, line switching, teleprocessing, etc., the number of operations to monitor simultaneously may be very high, and the usual methods of timer queues or multiple counters become time consuming. The described method enables control of the duration of many operations simultaneously, using a unique counter. This result is achieved by means of special control words, for running various time counts, and special tables (Time Survey Matrices) for registering and performing the required surveys. DEFINITIONS Timer Count Word.+

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Controlling the Duration of Multiple Events

It is often necessary in a program to ensure that a given operation does not exceed a specified duration. (Sector seek operation on a disk, for example. In some applications like process control, line switching, teleprocessing, etc., the number of operations to monitor simultaneously may be very high, and the usual methods of timer queues or multiple counters become time consuming. The described method enables control of the duration of many operations simultaneously, using a unique counter. This result is achieved by means of special control words, for running various time counts, and special tables (Time Survey Matrices) for registering and performing the required surveys. DEFINITIONS Timer Count Word.+

The time base is given to the program by a real-time clock of the type usually found in computers.

A single word in core storage, the "Timer Count Word" is incremented by one at regular intervals, provided by the time base. The increment interval corresponds to the smallest time span which has to be monitored.

In this Timer Count Word, a given bit will switch successively from 0 to 1 with a periodicity which corresponds to its position in the word, and is also a power of two of the count period. Segments

The Timer Count Word is divided into segments of consecutive bits, which may overlay each other.

A segment defines a class of time control (i.e., 1 to 10 seconds 10 to 50 minutes...). The lower bit of the segment is related to the time resolution desired for the class (1 second, 10 minutes). The highest bit of the segment is related to the longest period to be monitored in the class (10 seconds, 50 minutes). A segment is materialized by a string of bits equal to one in a storage word, all other bits in the word being equal to zero.

A mask (Logical And) of a segment applied on the Timer Count Word followed by a shift right provides the current time value in the class. Users

Users are events or operations which have to be controlled in time. They are generally interested in one Class of time span only, i.e., the required time resolution is in the range of milliseconds, seconds or minutes, etc. Therefore, each user is associated to one class of time span, and there is one or several "Users words" per "segment word", or class.

A particular user is addressed by its bit position in the "user word". A one bit in this position indicates that time control is required now for that user. Time Survey Matrices.

A set of tables, arranged in a matrix form, are used for time monitoring. There is one matrix per class of time span. A column of the matrix is associated to a user by the same bit position as in the user word.

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Each row of a matrix is associated to one of the time values provided in the c...