Comment by teach

This isn't especially related to the article, but when I was at university my first assembler class taught the Motorola 680x0 assembly. I didn't own a computer (most people didn't) but my dorm had a single Mac that you could sign up to use so I did some assignments on that.

Problem is, I was just learning and the mac was running System 7. Which, like MS-DOS, lacked memory protection.

So, one backwards test at the end of your loop and you could -- quite easily -- just overwrite system memory with whatever bytes you like.

I must have hard-locked that computer half a dozen times. Power cycle. Wait for it to slowly reboot off the external 20MB SCSI HDD.

Eventually I took to just printing out the code and tracing through it instead of bothering to run it. Once I could get through the code without any obvious mistakes I'd hazard a "real" execution.

To this day, automatic memory management still feels a little luxurious.