I was in the room with Ward Christensen when he got his later model (with a hard drive) Toshiba out of the box and realized he had no 3.5" drives on his other machines, and thus no way to get data to it. He hacked together enough of Xmodem in debug to try to download Qmodem (I think) via serial port, from another machine and after a few tries it was off to the races.
This will always sit in my mind as one of the greatest hacks of all time. Total time elapsed was less than half an hour.
For those who didn’t grow up in MS-DOS, “debug” was the absurdly limited assembler that shipped with the operating system, and was the only development tool available on a fresh install (apart from BASIC).
"debug" was truly the devil's spawn. Yet, it was always there. You always needed it at the time you had no other tool available, so you had to struggle through. Therapy was mandatory after any use of that utility.
Looks like Windows XP was the last version to ship with it?
I used debug to write some moderately serious (~5k lines of code) toy programs in assembly. It worked. Labeling it with insults is historical revisionism; it was part of the basic toolkit for how you hacked around on DOS computers of the time.
I learned a ton about low-level computer operations from using debug. It's more than an assembler, it's also a runtime environment with breakpoints and a debugger, and a hex editor. It really manipulates everything going on with the computer at a byte-by-byte level. I wouldn't have learned all that quite the same way from any "real" tools like MASM or the Norton debugger.
This will always sit in my mind as one of the greatest hacks of all time. Total time elapsed was less than half an hour.