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Binary-Weighted Delay Function

IP.com Disclosure Number: IPCOM000120567D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Lamana, M: AUTHOR [+2]

Abstract

In systems where it is a requirement to time the duration of an operation or to wait a specified amount of time before continuing to the next operation, the usual approach is to time tag the event, then enter it on a list. Periodically, and then, the list is examined and the time tags compared to the current time. If a match is found, then the event is considered to have "timed out" and the next function related to the event can be started.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Binary-Weighted Delay Function

      In systems where it is a requirement to time the duration
of an operation or to wait a specified amount of time before
continuing to the next operation, the usual approach is to time tag
the event, then enter it on a list.  Periodically, and then, the list
is examined and the time tags compared to the current time.  If a
match is found, then the event is considered to have "timed out" and
the next function related to the event can be started.

      If a way could be found to reduce the number of events which
must be processed each time a processing period has come due, then
the available amount of cumulative processing time acceptable for
dedication to the timing function itself will support a greater
number of events.  The term "pacing mechanism" or "pacing" is used to
refer to an algorithm which provides a means of timing events which
microcode has been directed to keep track of without suffering the
overhead increase per event which is typical of the classical time
monitoring functions.

      The pacing algorithm deals will a group of lists rather than
one list.  Each list in the group represents a fixed amount of time
based on a power of two.  The first list can represent a delay of one
unit (where a unit is the time between a consecutive running of the
list processing algorithm), the second list would be two units, the
third list eight units, and so on.  When a list processing time has
arrived, only one of these "pace lists" is examined. Processing a
list entails removing an event from the list and placing it on
another pacing list or passing the event on to the next step of its
processing.  To summarize:
     One of the pace lists is serviced aft...