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From: ralf@b.gp.cs.cmu.edu (Ralf Brown)
Newsgroups: comp.sys.ibm.pc
Subject: Re: control-P = PrtSc on PC/AT's
Message-ID: <18@b.gp.cs.cmu.edu>
Date: Tue, 17-Mar-87 12:38:59 EST
Article-I.D.: b.18
Posted: Tue Mar 17 12:38:59 1987
Date-Received: Wed, 18-Mar-87 07:23:16 EST
References: <246@applix.UUCP>
Organization: Carnegie-Mellon University, CS/RI
Lines: 35

Ctrl-P is only mapped into Ctrl-PrtSc if the CON device is in "cooked" mode
(which happens to be the default), in which case DOS also checks for ^S and
^C between each and every character output.  I have two little programs (40
and 44 bytes when assembled) that put CON into "raw" mode (no ^P, ^S, or ^C
checking) and back into cooked mode.  I will post them tonight, as they
are at home.

An added benefit of putting the console into raw mode is a great speed 
increase--DOS output on a PC can be nearly the speed of cooked output on
an AT.  In fact, by using NANSI.SYS, raw mode, and avoiding scrolling, a
file browser that I picked up recently achieves virtually the same 
performance as a file browser that writes directly to the screen memory!

The drawback of raw mode is that neither ^C nor ^Break is checked, so it is
not possible to interrupt a long TYPE command in the middle.


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| Snail: Ralf Brown                           --- Edsger Dijkstra             |
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+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+
| ARPA:  RALF@B.GP.CS.CMU.EDU            "Teaching COBOL ought to be          |
| AT&T:  (412) 268-3053 (school)          regarded as a criminal act"         |
| Snail: Ralf Brown                           --- Edsger Dijkstra             |
|        Computer Science Department                                          |
|        Carnegie-Mellon University      DISCLAIMER?  Who ever said I claimed |
|        Pittsburgh, PA 15213            anything?                            |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+