> For starters, some embedded controllers in racks in the auxilliary deisel generator control rooms have EPROMs which have been known to be erased by camera flashes in the past
Not being in EE, I didn't know that this was possible; and, with the knowledge that a bright flash erases EPROMs, that they'd be left in a position where this could occur. More interestingly, the NRO has a notice about it: http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-...
The government verbiage for the hack here (tape over the window) is amusing in itself:
> They also confirmed that the light from the Canon flash and the Polaroid flashbulb could be effectively blocked by "black bagging" the flash, or by blocking the EPROM window with "tin foil" held in place by clear cellulose tape, or by blocking the EPROM window with "standard electrical tape."
Not being in EE, I didn't know that this was possible
Not only is it possible, it has led to many interesting failure modes in the past since visible light doesn't usually erase an EPROM, but sometimes just flips a few bits. The n00b complaint, "it works fine until I turn on my desk lamp" used to be a pretty common one in EE labs and online help forums :-)
I don't buy it for a minute. You can leave an uncovered EPROM in direct sunlight for a week, and the data will probably survive.
I'd suspect a localized "EMP" transient from the camera flash before I'd suspect an erased EPROM. It takes a lot of energy, in the E=hv sense, to erase an EPROM.
Believe it: windowed EPROMS have been used as cameras. Their light sensitivity is legend.
[edit] actually I was wrong about that. The memory devices used as cameras were delidded RAMs, not EPROM. EPROMs are light sensitive, but too slow for that.
I remember seeing a motherboard or video card BIOS stored on EPROMs as a kid, and wondering what it would happen if I took the light-blocking sticker off and shined a black light in the computer while it was running. It is interesting, though not too surprising, that the EPROMs are exposed in the racks. If nobody's ever going to be in the room, why bother putting walls on the racks?
Also, it's probably a good thing that flash memory was invented before the ultraviolet LED, otherwise we might be stuck with LED-based EPROMs with painfully slow erase cycles ;).
Trident 8800CS! Had hi/lo eeproms with a reflective hologram sticker over the eeprom window. Now we upload microcode/firmware on bootup. We have things so good.
I loved my Trident. It was the first video card I owned that could do 1024x768. It's been so many years that I don't remember all the other steps I went through between Hercules and CGA to a modern nVidia, but almost every one of them was special in some way.
Since I was rather young at the time, my access to anything better was limited. Talking about mode X does make me nostalgic, though I used Allegro instead of writing my own low-level init code.
You used to erase eeprom with UV lights. I remember doing this back int he late 80's early 90's in my dads basement electronics lab. Fun stuff. Now we just flash everything with software. We have it much better these days.
Not being in EE, I didn't know that this was possible; and, with the knowledge that a bright flash erases EPROMs, that they'd be left in a position where this could occur. More interestingly, the NRO has a notice about it: http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-...
The government verbiage for the hack here (tape over the window) is amusing in itself:
> They also confirmed that the light from the Canon flash and the Polaroid flashbulb could be effectively blocked by "black bagging" the flash, or by blocking the EPROM window with "tin foil" held in place by clear cellulose tape, or by blocking the EPROM window with "standard electrical tape."