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My two "favorite" hardware bugs: dead RAM stick partially corrupts memory pseudo-randomly (no ECC) so everything sort of works but is really weird. CPU that for
by southerntofu 5y ago
My two "favorite" hardware bugs: dead RAM stick partially corrupts memory pseudo-randomly (no ECC) so everything sort of works but is really weird. CPU that for some reason misbehaves so much without a newer non-free microcode/firmware version, so that everything sort of works but breaks in random way (just like broken RAM).
The former really plays with my nerves because i tend to question the whole universe before i question the hardware. The latter is even more evil because memtest/smartctl won't complain about anything.. i'm not sure if there's an equivalent utility to test CPU health? Anyway it took me a while to even think of trying non-free intel-microcode, as of the CPU/kernel wouldn't produce a helpful error message like "You bought hardware which is pure shit. Please install some more binary shit in order to use it at all without losing your sanity."
- toast0 5y agoOn CPU issues, at my 4-year, we did a bunch of projects with 68HC11s, which stop branching when voltage is low. After a few episodes of this, I eventually figured out when it started running straight through everything, it was time to recharge the batteries (and probably take a break anyway)
- Hackbraten 5y agoI love this. Reminds me of a sleep-deprived driver who keeps missing highway exits.
- toast0 5y agoFun extra fact. The debugger would work, and you could single step through it not taking branches it should clearly take. My professor told us it was designed to be a low voltage cpu, but they had some issues, so 5v only... I'm guessing this was the issue.
- jakeinspace 5y agoWe've solved the halting problem! Just lower the voltage, ignore branch/jump instructions, and run straight through.
- Hackbraten 5y agoI smell a new esolang: Alan. Has a dozen branch instructions but they’re all ignored.