Path: utzoo!attcan!uunet!husc6!bloom-beacon!gatech!dscatl!wa4mei!jcw
From: jcw@wa4mei.UUCP (8125)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Re-Mapping DOS Interrupt 0x21 Vector
Keywords: DOS Universal Services, Interrupt 0x21
Message-ID: <1203@wa4mei.UUCP>
Date: 17 May 88 12:15:39 GMT
References: <45@radix>
Reply-To: jcw@wa4mei.UUCP (John C. Wren)
Organization: KD4NC Ham Packet Radio Gateway, Marietta, Ga
Lines: 11



I have successfully re-vectored int 21 for an application at work.  The
best method seems to be to create a device driver that does nothing in
the main body, but contains code to perform your application.  Grab the
int 21 vector during the INIT routine of the driver, and store it off.
What this effectively gives you is a terminate and stay resident piece
of code that garuntees (or at least more reliably than once COMMAND.COM
is running) you an un-contaminated int 21 vector.  If you're interested
in more gory details, reply via mail.
                                                  - John C. Wren