pbMay 26, 2024
When your computer crashes the blue screen still works. Why not make the whole computer out of blue screen?
Show threadmccMay 26, 2024

@pb @anildash I don't think you wanted a serious answer but I am going to give you one.

What you are describing is MacsBug! Pre-"X" Macintoshes had a thing you could install that was a sort of CPU debugger. You could get to it with a keystroke, or it would launch if a program specifically requested debugger entry… or if there was a crash! (I forget if it did this by default or if you had to configure it, but I believe it was an option.) When you entered it all normal CPU activity would halt.

Show threadmccMay 26, 2024
@pb @anildash So like imagine if the Windows bluescreen had a command line and various little basic utilities, and that's MacsBug. By default you could poke and pop memory, disassemble the area around the instruction pointer and the stack above it, and there was a little calculator built in. But you could also install macros to do arbitrary tasks. So it was basically like a second operating system hiding inside the mac that could run whatever "program" you wanted at its command line.
Show threadmcc

@pb @anildash So the idea was supposed to be that if you're a programmer, when your program crashes you could use Macsbug to explore the crash and identify how to fix it. But it was also quite possible to use Macsbug to *undo* a crash, and resume normal operation of a crashed program.

(And sometimes people would just pop in to MacsBug to use the calculator, as it was v convenient. But this became a bad idea once Internet happened, because spending time in MacsBug could confuse the TCP/IP stack)

May 26, 2024 at 8:55pmWeb
Show threadmccMay 26, 2024

@pb @anildash MacsBug was like an upgrade for MiniBug— MacsBug was something you installed but MiniBug was built in and could always be invoked with a particular keystroke. But MiniBug was so simple, just a minimal memory debugger, it was unlikely you could ever do much with it.

…And MiniBug was itself kinda like a revamp of the "Monitor" for the Apple 1 and Apple 2, where it was more practical and *could* plausibly recover crashes due to the more predictable memory layouts of the time…