Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Jolly Roger Newsgroups: comp.sys.mac.system Subject: Re: How does OS-X behave with a dead SSD ? Date: 2 Dec 2016 17:54:12 GMT Organization: People for the Ethical Treatment of Pirates Lines: 57 Message-ID: References: <583b3a29$0$1567$c3e8da3$12bcf670@news.astraweb.com> <583b85ff$0$10986$c3e8da3$f017e9df@news.astraweb.com> <583bd7a6$0$1557$c3e8da3$12bcf670@news.astraweb.com> <291120161456080223%JimSGibson@gmail.com> <291120161828475976%nospam@nospam.invalid> <583e6990$0$51650$c3e8da3$f6268168@news.astraweb.com> <583f46c4$0$31396$c3e8da3$dd9697d2@news.astraweb.com> X-Trace: individual.net qN2t67l+oTARFh/kDHefvgK3BVCHfHAWZ5WULa8UNH8dsnNskL Cancel-Lock: sha1:iz/bhObuBSo0NOPMV8enpjfNuAM= Mail-Copies-To: nobody User-Agent: slrn/1.0.1 (Darwin) Xref: csiph.com comp.sys.mac.system:97496 On 2016-12-01, Alan Browne wrote: > On 2016-11-30 19:44, Jolly Roger wrote: >> On 2016-11-30, JF Mezei wrote: >>> On 2016-11-30 02:19, Jolly Roger wrote: >>>> JF Mezei wrote: >>>>> On 2016-11-29 22:20, Jolly Roger wrote: >>>>> >>>>>> Time Machine to back up to two different destinations, whenever the >>>>>> SSD does crap out, replacing it will be a simple matter of replace, >>>>>> then restore. It's completely a non-issue. >>>>> >>>>> You're assuming that you will notice it crapping out. Unlike >>>>> spinning rust discs, an SSD will continue to remain readable after >>>>> writes become a problem. >>>> >>>> Irrelevant; as soon as there is an issue that prevents either reads >>>> *or* writes, the OS will say so. >>>> >>>>> But you may encounter a situation where after saving a document, the >>>>> middle 4 blocks contain invalid data because the SSD was unable to >>>>> write those 4 blocks and nobody noticed. >>>> >>>> Now you're trying to claim macOS doesn't verify data that it writes >>>> to a volume during file saves? That's not just completely false; it's >>>> laughable! >>> >>> Wow. you have little understanding of how an OS works. >> >> Your claim that an SSD write will fail without the OS or the user >> noticing is both false and idiotic. Of *course* the OS will know if a >> write fails - an error will be generated. And of *course* the user will >> be notified of the failure - an error message will be displayed on the >> screen. > > What precisely does OS X do that confirms correct recording of a sector > (or block) write? The storage device returns a success of failure on each write. The OS trusts the storage device to know whether or not the operation was successful. > Does it read the sector ( or block) back? That is > the sole way to verify to perfection that there was not a write failure. The OS trusts that the storage device was correct when it claimed the operation completed successfully. > I can't find anything online showing how OS X detects a disk write > failure. Any deep references? Meh. Not worth my time. -- E-mail sent to this address may be devoured by my ravenous SPAM filter. I often ignore posts from Google. Use a real news client instead. JR