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The wording of the title makes for a kinda misleading implication. This is pretty standard - they're called e-fuses. It isn't "blowing" in the sense that an act
by BillinghamJ 8y ago
The wording of the title makes for a kinda misleading implication. This is pretty standard - they're called e-fuses. It isn't "blowing" in the sense that an actual fuse does, but it is permanently/irreversibly writing bits to indicate the minimum version.
- kmm 8y agoIf not by actual fuses, how is it implemented? There has to be some sort of physical change for it to survive without power indefinitely
- crankylinuxuser 8y agoA read operation determines if the connection is "connected" or "disconnected". It actually is litte bits of wire inside silicon that get over-current'ed and do burn away. And then a read operation returns "Disconnected". There's no way to 'reconnect' a eFuse, in the way there's no way to reconnect an automotive fuse. So yes, eFuses are a form of hardware destruction.
- zaksoup 8y agoI think the parent is being pedantic. All the literature I could find on eFuses (including the wikipedia article) either used 'blowing' to refer to permanent writing, or '"blowing"' (in scare quotes). Whether or not that is descriptive of the physical process that's occurring, it certainly seems to be a reasonable term for anybody to use to talk about the functionality of eFuses.
- kevin_thibedeau 8y agoExcept that in many cases the "fuses" can be reset by wiping the firmware from the part and restoring it to a factory clean state.
- pjc50 8y agoThen it's not really a fuse in the normal chip sense.
- kevin_thibedeau 8y agoThe normal chip "fuses" aren't fuses anymore. They're just a section of EEPROM or flash with control circuitry altered to make them write-once only. Real fuse programming required generating high voltages and subjecting the die to high currents and localized thermal stress that modern ICs don't tolerate well.
- khedoros1 8y agoThat sounds like a flag, not an eFuse. I'd expect something called an eFuse to be some form of one-time programmable non-volatile memory.
- samuellavoie90 8y agoProbably just some 'Write Once' Memory, where they can raise bits to 1 but can't lower them back to 0. (Or the other way around, depending on the memory)
- rusk 8y agoWhich is typically implemented as a fuse no? I’m struggling to remember my undergrad EE but I think that’s a thing ... EPROM back in the day used to work like this. You’d use an ultraviolet light to remake all the fuses when you wanted to wipe and start again. Flash came along then and made these technologies obsolete.
- meesterdude 8y ago> This is pretty standard Doesn't make it right. It does not sound like a design decision made on the behalf of the consumer. This is planned obsolescence.
- frenchie4111 8y agoHow is it planned obsolescence?
- omegaworks 8y agoThere are only 32 such fuses.
- sov 8y agoSo? How would blowing all 32 "fuses" make the console obsolete?
- apostacy 8y agoIt would be obsolete because it would no longer be as usable. This has happened to several phones, and especially Apple devices. At least when Microsoft forced people to update to Windows 10, you could still install Windows 7 later if you really wanted. But your iPad or phone can go from being fairly usable and fast, to being slow and useless with the last update. And it almost always does.
- sov 8y ago> It would be obsolete because it would no longer be as usable. What on Earth makes you think this?
- apostacy 8y agoPermanently slowing my device down = Making my device less usable = obsolete I could have gotten many more years of usability out of it, but they nearly bricked it with an update that I could not say no to.
- dv_dt 8y agoSometimes its not even permanent and the "fuse" is more of a term to indicate that the value is non-volatile.
- apostacy 8y agoApple and Google will coerce you into installing updates that irreversibly remove functionality, so think describing the fuses as being "blown" is the best word to use, since it implies damage being done to your device. I can at least understand game console developers doing this. But it has become standard practice now. I forgot my new pin on my iPad, and Apple forced me to take an update that I didn't want in order to restore it, which broke several features that I liked[1]. After iOS8, there is no way to decline updates, they will just keep getting downloaded. My mother and grandmother both had their iPads hobbled by destructive updates as well. My Mom was going to give her old iPad 4 to one of her students so they could use this learning app, but Apple updated her iPad while she was sleeping one night, and iOS10 is so slow it is barely usable. Can we please stop excusing this behavior by using neutral language? Companies clearly know that these updates are unwanted, or else they would let your roll them back. Retroactively removing features and damaging devices that people have paid for should be illegal. [1]: https://news.ycombinator.com/item?id=11986500 https://news.ycombinator.com/item?id=11986500
- koala_man 8y ago>Google will coerce you into installing updates that irreversibly remove functionality Do you have an example? On Android you're generally free to downgrade at any time, as long as the user data partition is cleared in the process.
- khedoros1 8y agoOne that comes to mind for me, with a specific Google app: Google removed SMS from newer versions of their Hangouts app over a year ago. I kept the program at the last version to have SMS. Pop-ups appeared periodically asking me to update the app. After about a year, launching the app starting showing a page "This version of Hangouts is no longer supported. To continue, please update the app." Of course, at that point, I moved to one of their currently-supported apps...but it means that my Hangouts conversations are in a different place than my SMS conversations.
- nkristoffersen 8y agoPerhaps you don't work in software, but you definitely want constant updates for an internet connected device. Apple has a track record for providing software updates for a long time past initial device release. Do you think more manufactures should be following their lead? The "cyber" world would be a much more secure place with constant updates.
- slededit 8y agoA common way to implement this is to have a resistor that literally does blow open due to over current. Pretty much the same principle as a fuse which is why it has that name.
- dang 8y agoOk, we've removed the blowing fuses from the title above.
- phire 8y agoThere are many possible ways to implement eFuses in silicon, such as NOR flash without the erase hardware. Starts in the 1 state, you can program it to 0, but you can't ever erase it back to 1 without exposing the silicon to UV. But the original IBM implementation was based on "resisters" which were physically damaged by passing too much current through them. Technically it's not "burning", as there is no smoke or combustion. Instead it's taking advantage of the electromigration side effect. But blowing is the closest analogy, the silicon is irreversibly damaged, due to too much current. You can read more here: http://paris.utdallas.edu/ssiri08/Tonti_SSIRI_eFuse_V2.pdf http://paris.utdallas.edu/ssiri08/Tonti_SSIRI_eFuse_V2.pdf I have no idea which technology Nvidia used to implement their eFuses.
- kabdib 8y agoThese fuses don't necessarily stay blown; it's possible for them to mechanically heal. Consoles I've worked with have often blown multiple fuses and taken a vote (for controlling important features and version minimums).