On Thu, 1 Jun 1995 11:03:22 +0100 (BST), Tim Paveley said: > The other day, I was happily playing around getting my Sam to report odd > error messages (like 124, 67, etc.) and I noticed that some of them, around > 127, 128 tried doing something with the disk drive.
The usual way to make an error is to execute the machine code instruction RST 8 (op code 207) followed by a data byte. Were you doing this? Anyway, various disk operating systems have what they call hook codes. The ZX microdrive even had them. :-) A hook code is a way to call the DOS to do things like searching for a file on the disk. Funnily enough, hook codes are accessed by writing RST 8 followed by a data byte. If you ask me it's silly, but there you go. In SamDOS, the difference between a hook code and an error is that the hook codes have values over 127. I think. So, did you BOOT before doing your experiments? If so then that might be why you got those effects. If not then it's a mystery... imc
