[onre]

I've gotten an OS to run on a new platform with a debugging tool portfolio consisting of a handful of LEDs and a pushbutton. After getting to the point where I could printf() to the console felt like more than anyone could ever ask for.

Anecdote aside, it certainly doesn't hurt to be able to debug things without a debugger if it comes to that.

[shadowgovt]

Since most of my work is in distributed systems, I find the advice to never printf downright laughable.

"Oh sure, lemme just set a breakpoint on this network service. Hm... Looks like my error is 'request timed out', how strange."

That having been said: there are some very clever solutions in cloud-land for "printf" debugging. (Edit: forgot this changed names) Snapshot Debugger (https://github.com/GoogleCloudPlatform/snapshot-debugger) can set up a system where some percentage of your instances are run in a breakpointed mode, and for some percentage of requests passing through the service, they can log relevant state. You can change what you're tracking in realtime by adding listeners in the source code view. Very slick.

[mark_undoio]

> "Oh sure, lemme just set a breakpoint on this network service. Hm... Looks like my error is 'request timed out', how strange."

Time travel debugging (https://en.wikipedia.org/wiki/Time_travel_debugging) can help with this because it separates "recording" (i.e. reproducing the bug) from "replaying" (i.e. debugging).

Breakpoints only need to be set in the replay phase, once you've captured a recording of the bug.