CBRK.COM Copyright (C) 20 January 1992 Robert Clark Revision 1.00 All rights reserved. ---------------------------------------------------------------------- Written using the A86 assembler. This program disables Ctrl-Break interrupt processing by changing the interrupt vector to point to a routine that writes a BELL to the console and returns via an IRET. To use, simply type CBRK + to disable Ctrl-Break, or CBRK - to re-enable Ctrl-Break CBRK may be loaded high without trouble. CBRK can not be unloaded from memory, although its functionality can be disabled with CBRK - The DOS Ctrl-Break flag checking is also turned OFF. DOS will still check for Ctrl-Breaks during video output, console input, et cetera. CBRK.COM leaves 352 bytes of resident code in DOS RAM. This is accomplished by using the DOS Int 21/31 (Terminate-and-Stay Resident) exit. The remaining (loader) code is not made resident. Subsequent attempts to run CBRK result in a normal exit using DOS Int 21/4C (Terminate with Errorcode). CBRK sets the following errorlevels that may be used by other programs: 0 = Successful Ctrl-Break enable or disable. 1 = CBRK already resident--can't load again w/o disabling first. 2 = CBRK not resident--can't disable w/o loading first. 3 = Syntax error--no action taken. That's all there is to it. Stay tuned for legalese stuff below.... ---------------------------------------------------------------------- LEGALESE: I'll make it very simple. I warrant this program to take up disk space. Other than that, I assume no liability for real or imagined harm or loss of life and property. Use this utility at your own risk. Keep out of reach of children. Let's see, what else.... Oh! Almost forgot.... CBRK is copyrighted 1993 by Robert B. Clark, all rights reserved. This program is hereby released as FREEWARE. By FREEWARE, I mean that you may use this utility until Armageddon if you wish without compensating me. You may also disseminate this archive to the four corners of the Earth if you wish, as long the archive is COMPLETE. This does NOT mean that this program is released into the PUBLIC DOMAIN. I retain all rights to CBRK. Of course, I wouldn't be adverse to any donations, but let's face it: I only spent a couple of hours on this thing. If you like, drop me some e-mail and tell me if you've found a use for CBRK. ---------------------------------------------------------------------- SUPPORT: Ha ha! You expect support for a FREE utility? Really, if you need assistance using CBRK, or want to suggest some improvements for future releases (bwahahaha), contact me via e-mail: Internet E-mail: rclark@iquest.net World Wide Web : http://www.iquest.net/~rclark/ClarkWehyr.html ---------------------------------------------------------------------- REVISION HISTORY Rev 0.90 1/20/93 Completed basic TSR detection technique (using the signature word encoded at the end of the TSR). Rev 0.95 1/25/93 959 bytes 2-2-93 9:44a Fixed problem with re-enabling original Ctrl-Break vector. Rev 0.97 8/4/93 Revised documentation. Rev 1.00 11/29/93 959 bytes 11-29-93 1:00a CBRK.COM 158 bytes 11-29-93 1:00a CBRK-NM.COM FIRST RELEASE, v1.00 Cleaned up documentation; made a version without confirmation messages (CBRK-NM). ###