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I taught myself x86 assembly from a book as a pre-internet teenager. My first .COM printed exactly what it was supposed to on the screen. Then it printed a bunc

I taught myself x86 assembly from a book as a pre-internet teenager. My first .COM printed exactly what it was supposed to on the screen. Then it printed a bunch of random junk and my computer rebooted. This happened every single time I ran the executable. Eventually I actually read the first chapter properly and added MOV AH,4CH / MOV AL,0 / INT 21H. When my executable returned to the DOS prompt this time after running it, I felt like my mind had just expanded 10-fold as I realised what had been happening.

olddustytrail 4y ago
Did you get that "This machine does whatever I can tell it to do!" feeling? And then you wonder what can you think to tell it to do. The wonder of computers.
- ddingus 4y ago
  That is an amazing feeling! Then it hits: that crash, bug, unexpected behavior is definitely my fault! Lol, good times when one works on a routine that executes, crashes and burns long before that finger loses contact with the "return" key!
throwaway_dcnt 4y ago
Or? MOV DX, 200 / INT 27H
raxxorraxor 4y ago
What did cause the reboot? Is this some kind of DOS watchdog that reboots the system because your program didn't exit gracefully?