Browse Prior Art Database

Adaptive Prediction Minimizes Data Overrun and Underrun

IP.com Disclosure Number: IPCOM000114189D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Behrs, JR: AUTHOR

Abstract

Disclosed is a software routine in a Device control program that manages the flow of data from a data server ("the Server") to a buffered output device ("the Device") such that data is received at the Device slightly before the Device finishes with previous data. The goal is to prevent Device underrun without delivering data to the Device much earlier than the data is needed, which can cause the buffer size to be exceeded and hinder the ability of the Server to deliver that data to some other available Device.

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Adaptive Prediction Minimizes Data Overrun and Underrun

      Disclosed is a software routine in a Device control program
that manages the flow of data from a data server ("the Server") to a
buffered output device ("the Device") such that data is received at
the Device slightly before the Device finishes with previous data.
The goal is to prevent Device underrun without delivering data to the
Device much earlier than the data is needed, which can cause the
buffer size to be exceeded and hinder the ability of the Server to
deliver that data to some other available Device.

Factors affecting the flow of data are:
  o  Devices that requires input at a rate that varies with data
      content,
  o  The speed and distance of the network,
  o  The speed of the host,
  o  The number of concurrently executing processes and other
      processing factors.

In addition, each device and server may have different operating
characteristics.

      The Device control program calculates the optimal point in time
when to request more data from the Server.  The Device control
program estimates the Device remaining busy time ("Busy-Time").  When
Busy-Time is equal to the estimated value of network delay
("Network-Delay"), the Device control program signals the Server that
it is ready for additional input ("Bytes-Requested").  If the
estimates of Busy-Time and Network-Delay are accurate, the Device
control program will receive Bytes-Requested in a timely manner,
eli...