Blackout Bricks



  • Ten to fifteen things make me think WTF everyday, sometimes I even think about writing a post about all the WTF I have encountered since starting in this job, sometimes I even start but then give up once I realise the enormity of the task I so foolishly embarked upon.

    So rather than try to rant about everything I will confine myself to the product I find myself working on today.


    The product which I shall call the B600 (not its real name) is used around the world to analyse gasses, it is subject to many checks and balances imposed by law, various bureaucrats, traceable standards of calibration and regular testing run by various national metrology institutions (NIST, UKAS, Etc..).
    As such when it comes to actually doing its job it is very good, however peek under the hood and you will be surprised at how it does it.


    Before you even reach the WTF in the software you find that you will be re-programming this thing pretty regularly even if you don't make any changes.
    This is because the older models were designed to store their software not in flash, no not in an EEPROM, not in SRAM but in volatile RAM with a battery backup.
    That's right folks, if you leave it unplugged for too long it bricks itself!


    This issue doesn't show up too often in the field as these things are left plugged into the mains 24/7 and have a large lead acid battery built in, but of course every now and again one is moved, or put into storage or just subjected to an unusually long blackout and the software disappears into the wind...


    The solution? Every unit was sold with an accompanying UPS!



  •  old cartdrige save games were also stored that way

    granted they had ROM so they wouldn't be bricked...



  • @EncoreSpod said:

    Ten to fifteen things make me think WTF everyday, sometimes I even think about writing a post about all the WTF I have encountered since starting in this job, sometimes I even start but then give up once I realise the enormity of the task I so foolishly embarked upon.

    So rather than try to rant about everything I will confine myself to the product I find myself working on today.


    The product which I shall call the B600 (not its real name) is used around the world to analyse gasses, it is subject to many checks and balances imposed by law, various bureaucrats, traceable standards of calibration and regular testing run by various national metrology institutions (NIST, UKAS, Etc..).
    As such when it comes to actually doing its job it is very good, however peek under the hood and you will be surprised at how it does it.


    Before you even reach the WTF in the software you find that you will be re-programming this thing pretty regularly even if you don't make any changes.
    This is because the older models were designed to store their software not in flash, no not in an EEPROM, not in SRAM but in volatile RAM with a battery backup.
    That's right folks, if you leave it unplugged for too long it bricks itself!


    This issue doesn't show up too often in the field as these things are left plugged into the mains 24/7 and have a large lead acid battery built in, but of course every now and again one is moved, or put into storage or just subjected to an unusually long blackout and the software disappears into the wind...


    The solution? Every unit was sold with an accompanying UPS!

    That is a fucking golden Rube Goldberg solution right there.



  • @EncoreSpod said:

    ... in volatile RAM with a battery backup.
    That's right folks, if you leave it unplugged for too long it bricks itself!
    Back in the day that was the only way to do things like that. I even remember nice, full sized ISA cards of battery backed RAM that you could add to PCs. Even now I work with products that have a built in battery that while it won't brick itself if it runs down, it will lose all user written software and configuration

    Bah, humbug, get off my lawn, onion on my belt



  • @OzPeter said:

    @EncoreSpod said:
    ... in volatile RAM with a battery backup.
    That's right folks, if you leave it unplugged for too long it bricks itself!
    Back in the day that was the only way to do things like that.

    Isn't that how many cheap printers still work?



  •   @OzPeter said:

    @EncoreSpod said:
    ... in volatile RAM with a battery backup.
    That's right folks, if you leave it unplugged for too long it bricks itself!
    Back in the day that was the only way to do things like that. I even remember nice, full sized ISA cards of battery backed RAM that you could add to PCs. Even now I work with products that have a built in battery that while it won't brick itself if it runs down, it will lose all user written software and configuration

    Bah, humbug, get off my lawn, onion on my belt
    back in the day there was also ROM where static information (like a bootstrap "load configs from serial port") data could be stored



  • @OzPeter said:

    Bah, humbug, get off my lawn, onion on my belt
     

    Nothing like a good Simpsons reference from the 90's, back when they were hip (Kids do still use that word?).

    The important thing was that I had an onion tied to my belt, which was
    the style at the time. You couldn't get white onions, because of the
    war. The only thing you could get was those big yellow ones...  - Grandpa Simpson

     

    On topic, PLCs still use battery backups today to store images in volatile memory.  Who says I don't work in a cutting edge industry...



  • @EncoreSpod said:

    That's right folks, if you leave it unplugged for too long it bricks itself!
    We had a piece of equipment like that a few years ago.  The default configuation settings that were stored in ROM were useless so it took a lot of fiddling to get it into a usable condition. And if you left it unplugged too long, the battery died and you had to take it to That One Guy® who had managed to figure out how to program it. There's an instruction manual, but its written in Japanese.

    There was a long Thangsgiving weekend coming up so I made sure to leave the unit plugged in for the 4 days that nobody was around. That's when we discovered that the charger doesn't detect when the battery is fully charged, and so it fries the battery. Which causes the unit to lose its configuation and have to be reprogrammed. After you buy a new battery. Probably a special order. From Japan.



  •  I had a camera once that was like that - it lost all of its pictures (stored in the 200KB(!) of RAM) if you took the battery out.



  • @ratchet freak said:

     old cartdrige save games were also stored that way

    granted they had ROM so they wouldn't be bricked...

    Those batteries also lasted about a decade or two, rather than a couple days.



  • @EncoreSpod said:

    The solution? Every unit was sold with an accompanying UPS!

    Yo dawg we heard you liked battery backup etc etc etc

    But right now there's a brownout and my UPS has gone on battery power. Can I get a UPS for the UPS?



  • Some old arcade machines also stored the game code in RAM instead of ROM, backed by a battery which was mounted somewhere else on the circuit board.

    Reason was to make it harder to copy/pirate the ROM... (if you remove the chip, the power will be cut off and it erases itself)

    If you ever buy an arcade machine (or arcade circuit board) on ebay or somewhere, try first to find information whether its "ROM" is battery backed RAM, and if yes verify before buying that the machine indeed still works and not "worked the last time I tried it".



  • @flabdablet said:

    @EncoreSpod said:
    The solution? Every unit was sold with an accompanying UPS!

    Yo dawg we heard you liked battery backup etc etc etc

    But right now there's a brownout and my UPS has gone on battery power. Can I get a UPS for the UPS?

    You could, but then that UPS would need a UPS, and then it's just turtles, man.



  • @The_Assimilator said:

    @flabdablet said:
    @EncoreSpod said:
    The solution? Every unit was sold with an accompanying UPS!

    Yo dawg we heard you liked battery backup etc etc etc

    But right now there's a brownout and my UPS has gone on battery power. Can I get a UPS for the UPS?

    You could, but then that UPS would need a UPS, and then it's just turtles, man.

     

    Can't you just connect the second UPS to the first one?

     



  • @DaarkWing said:

    On topic, PLCs still use battery backups today to store images in volatile memory.  Who says I don't work in a cutting edge industry...
    You're not at the cutting edge of the industry. Newer models dump the contents of their volatile memory to non-volatile Flash when they lose power.@anonymous234 said:
    Can't you just connect the second UPS to the first one?

    That's actually a really... bad idea. Most consumer-grade UPSs need a relatively clean incoming waveform but put out a really crappy output waveform. If you daisy-chain them, the second UPS will never charge itself properly because it's being fed the garbage waveform from the first UPS. Best case scenario, it never charges and you get no benefit; worst case scenario, it kills itself trying to process the garbage waveform and dies a premature death.

    Then again, most people have no idea that it's a really bad idea to put a laser printer or copier on a UPS, either.



  • @anotherusername said:

    crappy output waveform.
     

    What's a crappy waveform?



  • @dhromed said:

    @anotherusername said:

    crappy output waveform.
     

    What's a crappy waveform?

    Depends on what sort of waveform you want. Usually you want one that is sinusoidal, but some devices aren't as picky about it as others.



  • Exactly how freakishly distorted do these things output the original AC before a crude device such as a UPS can't eat it anymore? We're not doing signal processing near 1/2f here, so a little distortion shouldn't matter.



  • @dhromed said:

    Exactly how freakishly distorted do these things output the original AC before a crude device such as a UPS can't eat it anymore? We're not doing signal processing near 1/2f here, so a little distortion shouldn't matter.

    For about 0.2 seconds I considered getting the scope out and seeing what the waveform looked like. Then I remembered that if I wanted to electrocute myself playing with 120 VAC today, there's a light at home that doesn't work and I still haven't figured out what breaker it's on. I think I've narrowed it down to either the fixture or the wiring between the switch and the fixture. The bulb works and the switch is brand-new (and yes, I managed to electrocute myself while I was replacing it)...


  • Winner of the 2016 Presidential Election

    @anotherusername said:

    @DaarkWing said:
    On topic, PLCs still use battery backups today to store images in volatile memory.  Who says I don't work in a cutting edge industry...
    You're not at the cutting edge of the industry. Newer models dump the contents of their volatile memory to non-volatile Flash when they lose power.@anonymous234 said:
    Can't you just connect the second UPS to the first one?

    That's actually a really... bad idea. Most consumer-grade UPSs need a relatively clean incoming waveform but put out a really crappy output waveform. If you daisy-chain them, the second UPS will never charge itself properly because it's being fed the garbage waveform from the first UPS. Best case scenario, it never charges and you get no benefit; worst case scenario, it kills itself trying to process the garbage waveform and dies a premature death.

    Then again, most people have no idea that it's a really bad idea to put a laser printer or copier on a UPS, either.


    YHBT



  • @anotherusername said:

    Most consumer-grade UPSs need a relatively clean incoming waveform but put out a really crappy output waveform
    Don't they only output crappy waveform while on battery?



  • @joe.edwards said:

    YHBT

    Isn't that some kind of icecream, like Volkswagen-Das?



  • @ender said:

    Don't they only output crappy waveform while on battery?

    What do you think they'll be on if each UPS is plugged into the other?

    Actually, don't answer that. The fact that anyone is treating the original comment as something other than a joke is making my brain hurt.



  • @anotherusername said:

    @dhromed said:

    Exactly how freakishly distorted do these things output the original AC before a crude device such as a UPS can't eat it anymore? We're not doing signal processing near 1/2f here, so a little distortion shouldn't matter.

    For about 0.2 seconds I considered getting the scope out and seeing what the waveform looked like. Then I remembered that if I wanted to electrocute myself playing with 120 VAC today, there's a light at home that doesn't work and I still haven't figured out what breaker it's on. I think I've narrowed it down to either the fixture or the wiring between the switch and the fixture. The bulb works and the switch is brand-new (and yes, I managed to electrocute myself while I was replacing it)...

    Over here we use 240V so you get twice the buzz when you brush against that heatsink someone decided to attach to the live centre pin of some rectifier. Great fun.



  • @EncoreSpod said:

    @anotherusername said:
    @dhromed said:

    Exactly how freakishly distorted do these things output the original AC before a crude device such as a UPS can't eat it anymore? We're not doing signal processing near 1/2f here, so a little distortion shouldn't matter.

    For about 0.2 seconds I considered getting the scope out and seeing what the waveform looked like. Then I remembered that if I wanted to electrocute myself playing with 120 VAC today, there's a light at home that doesn't work and I still haven't figured out what breaker it's on. I think I've narrowed it down to either the fixture or the wiring between the switch and the fixture. The bulb works and the switch is brand-new (and yes, I managed to electrocute myself while I was replacing it)...

    Over here we use 240V so you get twice the buzz when you brush against that heatsink someone decided to attach to the live centre pin of some rectifier. Great fun.

    Shouldn't it be quadruple and not double? Doubling voltage will also double the current so power is quadrupled.

     


  • Discourse touched me in a no-no place

    @mott555 said:

    Shouldn't it be quadruple and not double? Doubling voltage will also double the current so power is quadrupled.
    Devices are typically about the same power so current limiters (breakers, fuses, etc.) are typically set to about half the level. Less of a problem with heating, but more insulation required. (Not that it's actually hard to insulate against either 120V or 240V.)


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