@ChrisInacio THAT'S THE COOLEST THING I LEARNED TODAY :D
On Sat, Apr 19, 2014 at 12:15 PM, Chris Inacio <nacho...@gmail.com> wrote: > > This has been quite the interesting thread. Way back long ago when I was > dong graduate work in microarchitecture (aka processor design) there were > folks who wanted to put an x86 processor in a satellite. x86, especially > at the time, was totally NOT qualified for use in space. The Pentium chip > (way back) had this really cool feature, that a single bit flip (e.g. > transient fault from alpha particle strike) would deadlock the processor > cold. If the correct bit in the reservation queue got toggled. > > So why the little story: Because people who really care about their > computation, for the longest time, didn't use x86 processors. They used > IBM mainframe processors, SPARC chips, etc. Why? Because, at least 10 > years ago, the ALU's in x86 chips had *zero* protection. So while there > may have been memory protection - the results of the ALU were completely > unprotected. PowerRISC, SPARC, PA-RISC, etc. at least all had parity > protected ALU's. Parity can't correct the calculation, but it can detect a > single bit fault. > > If you really want to protect your data end-to-end, you likely, still need > to buy a better class of machine. It might now be included in x86 class > processors, but I can't find anything that says the ALU's are protected. > The old addage, "you get what you pay for" still applies. If you're > interested, you can read about Fujitsu's SPARC 64 data protection: > http://www.fujitsu.com/global/services/computing/server/sparcenterprise/technology/availability/processor.html. > And I know this type of technology is in things like PowerRISC chips; IBM's > mainframe line has had ECC protected ALU's for a long time, (which I've > never spent the time to figure out how they work.) > > > > On Sun, Apr 13, 2014 at 12:34 AM, Michael Newbery <newb...@gmail.com>wrote: > >> On 13/04/2014, at 12:47 pm, Rob Lewis <groble...@gmail.com> wrote: >> >> I have no dog in this fight, but I wonder if possibly the late discovery >> of the need for ECC was a factor in Apple's abandoning the ZFS project. >> Unlikely they'd want to reengineer all their machines for it. >> >> >> I do not know, and am therefor free to speculate :) >> >> However, rumour hath it that Apple considered the patent/licence >> situation around ZFS to be problematic. Given the current litigious >> landscape, this was not a fight that they were willing to buy into. Note >> that the patent problem also threatens btrfs. >> You might discount the magnitude of the threat, but on a cost/benefit >> analysis it looks like they walked away. >> >> Likewise, some of the benefits and a lot of the emphasis of ZFS lies in >> server space, which is not a market that Apple is playing in to any great >> extent. It's not that ZFS doesn't have lots of benefits for client space as >> well, but the SUN emphasis was very much on the server side (which Oracle >> only emphasises). >> >> Now, with the OpenZFS model and in particular the options ("We'll support >> a,b and t, but not c or e") it's possible they might revisit it sometime >> (why yes, I am an incurable optimist. Why do you ask?) but I suspect they >> are more interested in distributed file systems a.k.a. the cloud. >> >> -- >> >> Michael Newbery >> >> "I have a soft spot for politicians---it's a bog in the west of Ireland!" >> >> Dave Allen >> >> >> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "zfs-macos" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to zfs-macos+unsubscr...@googlegroups.com. >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- > > --- > You received this message because you are subscribed to a topic in the > Google Groups "zfs-macos" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/zfs-macos/qguq6LCf1QQ/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > zfs-macos+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- --- You received this message because you are subscribed to the Google Groups "zfs-macos" group. To unsubscribe from this group and stop receiving emails from it, send an email to zfs-macos+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
