Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!usc!elroy.jpl.nasa.gov!ncar!midway!valley From: valley@uchicago (Doug Dougherty) Newsgroups: comp.os.msdos.programmer Subject: Re: Rebooting (SUMMARY) Message-ID: Date: 30 Nov 90 22:32:20 GMT References: <1990Nov30.154658.16398@wpi.WPI.EDU> Sender: news@midway.uchicago.edu (News Administrator) Organization: University of Chicago Lines: 27 jhall@wpi.WPI.EDU (John Clinton Hall) writes: >Thanks to all who responded to my message on how to perform a system warm boot. >In summary, to perform a system warm boot on the IBM, put the word 1234h in >location 0040h:0072h and JMP to location 0FFFFh:0000h. For example, the >following Debug code performs a warm boot: > MOV AX,0040 > MOV DS,AX > MOV AX,1234 > MOV [0072],AX > JMP FFFF:0000 >To cold boot the computer, just JMP 0FFFF:0000h. >-- >The highest sounds are hardest to hear. ## ## ## ##### ## jhall@wpi.wpi.edu >Going forward is a way to retreat. ## ## ## ## ## ## Worcester >Great talent shows itself late in life. ## ## ## ##### ## Polytechnic >Even a perfect program still has bugs. ######## ## ## Institute There are, in fact, some other "magic numbers" one can put into that location and have strange, magical, and mystical things happen. Unfortunately, I don't any of them. Incidentally, the boot code does ensure that there is a value other than 1234 in that location, so you shouldn't ever have to manually set it to ensure a cold boot.