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Comment by dmh2000 | Hacker News Reader

dmh2000

for me, its that the hardware doesn't always work or at least not as you expect. if you write workstation or server code, 99.99999% of your problems will be software bugs. But on an embedded system, especially something custom, you can have weird, intermittent hardware behavior that takes a lot of work to pin down. and sometimes you can't fix it so you workaround. It's both rewarding to get this stuff to work while at the same time extremely frustrating.

I've worked embedded systems for years but every year I tell my colleagues that I'm switching to IT so if my hardware doesn't work I can just throw it away and buy a new workstation.

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"Fun" problems from my embedded systems career in no particular order:

1)Writing device drivers for a chip that I can't get to work. Has to be my code, this is a basic function of the chip; why am I so stupid??!!? Finally call the vendor: oh, yeah we know about that bug, the next revision fixes it. Why isn't everyone else screaming about this problem? Well, you guys are only the second company to sample this chip. The first one found the bug!

2) System has to autoload a tray when operator closes the door. Works fine right up until it doesn't. Turns out some of the (visually opaque) trays are transparent at the infrared wavelength of the sensor that detects them.

3) (on a call with Field Service). Intermittent problem that seems to be software: a moving carriage is reporting errors, but only during certain moves. Field tech has replaced every relevant module and problem still happens. On a hunch I have him disable the safety interlocks and open all the doors to watch what happens. Problem is that there is a weak spot in an cable in an unrelated assembly that causes it to momentarily collide with the carriage, making the carriage fail to get to its destination. By the time they both stop moving, all hardware tests fine, so no one suspected the other assembly.

4) I love telling this one: hardware caught on fire because a jammed assembly caused a motor driver to overheat. Tester filed a bug against the software because it didn't report an error to the user. The CPU was fkn toasted!