April 16, 1987

                    CBOOT Version 2.0

I would like to thank all of the people who sent me money for
version 1.0 of CBOOT. This little program has proved to be far more
useful than I ever guessed and the only public domain program I
have written that ever made any money. For those of you who use
CBOOT and don't send any money - Grrr!

CBOOT is a very simple memory resident program which watches the
keyboard interrupt. waiting for someone to press the Left Shift,
the Alt key and the "B" key all at the same time. When this happens
a small menu appears on the screen. The menu allows you to re-boot
your PC in one of two ways. It allows you to issue a control-break
and it allows you to attempt an exit of your program. A new item,
restoring interrupts, is new with version 2.0.

The program works best under DOS 3.x, but will also work on DOS 2.x.
I have used some undocumented features of DOS to make escape from
run-away programs a little easier, and it appears that DOS 2.1 works
a little differently than 3.2 and the result is that escaping from a
program may not always clear memory under DOS 3.2. (My own opinion is
that DOS 2.1 is a better DOS, but I am running a network and have to
use 3.1 or 3.2).

MENU ITEMS:

0. Exit.
   Press 0 or Esc and get out of cboot and return to what you were
   doing.
1. Reboot (Ctrl-Alt-Del).
   This is the same as pressing the Ctrl-Alt-Del warm boot
   (three finger) combination. It is useful for programs which
   have disabled the keyboard Ctrl-Alt-Del.
2. Reboot with Memory Check.
   This is a Cold type boot and the system does its memory check.
3. Break (break-key).
   This is the same as pressing Ctrl-Break. CBOOT issues interrupt
   1B which may or may not help you out of a bad situation.
4. Exit Current Program.
   CBOOT issues interrupt 20h which is the traditional way to
   exit programs. Memory may or may not be restored. Do a CHKDSK
   to see if you got all fo your memory released.
5. Break Current Program.
   I have found that if you issue the DOS Break interrupt and then
   exit through interrupt 20h you sometimes have better results.
   If 4 doesn't work try this one.
6. Exit through Function 4C.
   This one seems to always give back the memory and close all
   the files, except once in a while (if Dos is in bad shape) it
   can cause the system to act odd. Experience will tell you if
   this works well with your programs. Use this one for disgraceful
   exits from basic after resetting the interrupts.
7. Reset Interrupts.
   Cboot remembers what the interrupts were when it started up.
   It can restore them. This must be done to exit out of Basic
   as basic does strange things with the interrupts. The only problem
   is that you loose any hooked memory resident programs that were
   loaded after CBOOT. And since Sidekick must be loaded after
   CBOOT - there goes sidekick and 64k of memory.

INSTALLING CBOOT.
   Put CBOOT in your autoexec.bat or else load it just before you
work on a particularly nasty program. There are no command options.
CBOOT takes about 2k of memory. Sidekick will get upset with CBOOT
if CBOOT is loaded after it. I think that Sidekick is not a very
well behaved program and it is banned from my system. It can be
very useful, but it is abusive of resources and makes programming
memory resident stuff difficult.

If you have any questions, drop me a line at:
       Keith P. Graham
       238 Germonds Road
       West Nyack, New York  10994

Remember to send the 5 bucks. If you can't afford it think of me
when you hit the lottery.
     Keith