TOMIII@MTUS5.BITNET (Thomas Dwyer III) (02/19/91)
I am aware of various TSRs which will return a machine to the DOS prompt via a hot-key from whatever state the computer happens to be in. The question is, how is this done (ie, what steps must be taken to make sure the machine doesn't go into some ultra-death state)? Thanks, Thomas Dwyer III Email: tomiii@mtu.edu Network Programmer tomiii@mtus5.BITNET Computing Technology Services Voice: (906) 487-2110 Michigan Technological University Fax: (906) 487-2787
rdippold@maui.qualcomm.com (Ron Dippold) (02/20/91)
In article <91050.025503TOMIII@MTUS5.BITNET> TOMIII@MTUS5.BITNET (Thomas Dwyer III) writes: >I am aware of various TSRs which will return a machine to the DOS prompt >via a hot-key from whatever state the computer happens to be in. The >question is, how is this done (ie, what steps must be taken to make sure >the machine doesn't go into some ultra-death state)? > What they do is save a copy of the machine state when they are invoked, all the interrupt vectors, memory allocations, etc. Then when you hit the hot key, they restore all this, putting you back in a previous state. The problem is that any program that locks up bad enough that you have to do this may not be well behaved enough to keep from writing random data all through memory, so your DOS and other loaded programs could be seriously messed up. The only time I use one of these is when I am writing a program that I know might lock up but that doesn't play around with memory too much.