Browse Prior Art Database

Hooking Function Calls to Hardware to Monitor Computer Output on Other Computers

IP.com Disclosure Number: IPCOM000110773D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26

Publishing Venue

IBM

Related People

Beck, JS: AUTHOR [+2]

Abstract

Disclosed is a method to monitor the output of one computer on another. Monitoring computer output entails hooking the function calls that produce output on a computer at one location and sending those function calls to a second computer. The first computer's output is recreated on the second computer by replaying those function calls on the second computer.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 23% of the total text.

Hooking Function Calls to Hardware to Monitor Computer Output on
Other Computers

      Disclosed is a method to monitor the output of one computer on
another.  Monitoring computer output entails hooking the function
calls that produce output on a computer at one location and sending
those function calls to a second computer.  The first computer's
output is recreated on the second computer by replaying those
function calls on the second computer.

      The output of one computer occasionally needs to be monitored
on another computer.  The computer output may occupy large amounts of
storage.  For example, visual output may be stored as bit-mapped
images.  The image of a PS/2's* VGA display occupies 156 kilobytes of
storage.  Storing other multimedia output such as video, voice or
music as digitized data also occupies large amounts of storage.

      Monitoring computer output entails capturing the computer
output at one location and sending it to another location for
playback.  The large amounts of storage needed to represent the
output, especially multimedia output, may degrade the performance of
monitoring the output.  This invention addresses how to decrease the
amount of data needed to monitor the output of a remote computer on a
local computer.

      The raw data of low level computer output is usually generated
by a higher level function or program.  This program makes function
calls to the output device which produces the raw output.  The amount
of computer storage needed to hold the data that describes a function
call is significantly less than the storage needed to hold the low
level computer output.

      Monitoring the output of a computer may be accomplished by
capturing or 'hooking' function calls made to the computer output
device.  These function calls contain all the commands necessary to
produce output on any computer.  These function calls can then be
sent from the remote computer where they were hooked to the local
computer.  The function calls may be executed on the local computer
to produce output identical to the output produced on the remote
computer.

1.  The remote computer captures the function calls.

2.  The remote computer sends the function calls to the local
    computer.

3.  The remote computer executes the function calls.

4.  The local computer executes the function calls.

5.  The same output is produced on both the local and remote
    computers.

      The capture, sending, and execution of the function calls may
be concurrent with the execution of other applications on both the
remote and local computers.  Computer tasks not involved with the
capture, communication, and playback of the function calls are not
affected by the monitoring of the computer output.  Operating systems
that support multitasking, such as OS/2*, will not have their
multitasking capabilities affected.

      This procedure does not limit the type of output which may be
monitored. ...