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From: sonny@charybdis.harris-atd.com (Bob Davis)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Word for Windows and DOS idle interrupt (INT28)
Message-ID: <5096@trantor.harris-atd.com>
Date: 16 Dec 90 15:28:54 GMT
References: <1522@netmbx.UUCP> <1990Dec13.220804.1611@vax5.cit.cornell.edu> <5094@trantor.harris-atd.com> <1537@netmbx.UUCP>
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Reply-To: sonny@trantor.harris-atd.com (Bob Davis)
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Organization: Advanced Technology Dept., Harris ESS, Melbourne, FL
Lines: 33

In article <1537@netmbx.UUCP> oeschi@netmbx.UUCP (Johann Deutinger) writes:
	[DELETIONS]
>
>There seems to be a minor misunderstanding: my background software (which
>is actually used to talk to our intelligent fax card) relies on being
>activated through the INT28 hook of TeSseRact, i.e. when DOS waits for
>keyboard input or in other I/O busy situation, it does an INT28. This
>in turn gives me the chance to do some background processing. If no INT28
>occurs (as in Word for Windows) I don't become called from anywhere. All
>other Windows application I have don't cause that. TeSseRact additionally
>calls INT28 on BIOS keyboard wait, this does not help in Windows which
>does not use the BIOS for keyboard I/O. In WfW, as soon as I pull down
>one of the menus, INT28 calls do occur, they don't show up as long as I
>am in the editing Window. A solution for that is very important to me
>because otherwise I could not send or receive faxes during WfW editing.
>
>Johann
>
	But doesn't this say that hooking ONLY INT28 is inadequate for
proper functioning (with Word for Windows) of the TSR you are developing?
	Doesn't this say that you MUST hook some OTHER interrupt that DOES
occur when editing in Word for Windows? Perhaps you also need to hook the
Timer Tick Interrupt 08 (or, better, INT 1Ch). These interrupts occur
18.2 times per second and you might be able to substitute your own
handler for providing your "background" FAX task. Care must be employed
when hooking the timer interrupt to avoid interference with time-sensitive
tasks.
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