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From: woodc@jacobs.cs.orst.edu (Major Havok)
Newsgroups: comp.lang.pascal,comp.os.msdos.programmer
Subject: Error intercepting.
Message-ID: <1991May31.081120.4742@lynx.CS.ORST.EDU>
Date: 31 May 91 08:11:20 GMT
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Organization: Oregon State University, CS Dept.
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Nntp-Posting-Host: jacobs.cs.orst.edu


  I was wondering if anyone can give me information on how to intercept
error handling procedures in DOS. I wish to be able to write a TSR
program that will send/receive data using a serial or parrellel port
if certain drive errors occur. I can't write a TSR using the critical
error handler because when you enter DOS it will reinstall the original
error handler. (Atleast I don't know how to write a TSR to hook onto
this interrupt handler.) Here is a description of the project that I
need this information for....

  I have two computers hooked up together using a parrellel cable. I
wish to install a TSR on both computers to allow them to operate 
similar to a LAN. One computer has hard drives labeled C: to E:, the
other has drives labeled C: to F:. At either machine I wish to be able
to access 'imaginary' drives G: to I:. DOS would get an error when I
try to access these drives from either machine, the TSR should
intercept this error message and attempt to establish a connection
with the other machine before verifying the error. If a connection 
can be made and drives G: through I: can be simulated, then the error
is canceled and data will be transfered from one computer to the other,
otherwise the error message is displayed and the normal error handler
will be invoked.
 
  Can anyone tell me if there is any way I can possibly latch on to
the critical error handler from DOS? If not, does anyone know of 
any other way to do this? Thanks in advance...

Chris Wood 
(woodc@jacobs.cs.orst.edu)