Thursday July 04 1996 01:21, Tom Clarkson wrote to Peter Watney:

 PW>> In order to completely disable Ctrl-Break you have to change the copy
 PW>> of Command.Com that your application happens to be using at the
 PW>> time. The reason is that for a number of operations Pascal is using
 PW>> DOS, and DOS no way to disable Ctrl-Break (legally), so whenever your
 PW>> Pascal application loading, or is temporarily passing control to DOS,
 PW>> even though you have SetCBreak set to false DOS will intercept the key
 PW>> stroke and interpret it.

 TC> not quite as complex as changing command.com... you use
 TC> getintvec/setintvec, and make an interrupt procedure. when your program
 TC> starts, you take control away from dos, and give it back on exit. in real
 TC> mode it stuffs up if the program crashes, but in protected mode messy
 TC> interrupts don't matter.

True, unless the problem relates, as mine did, to security from boot time
to power down, in which case you need to prevent access to DOS by
unauthorised people at any time.

Regards,
Peter

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