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Grzegorz Kulewski a écrit : > Hi, > > On Thu, 2 Nov 2006, Mikulas Patocka wrote: >> As my PhD thesis, I am designing and writing a filesystem, and it's >> now in a state that it can be released. You can download it from >> http://artax.karlin.mff.cuni.cz/~mikulas/spadfs/ > > "Disk that can atomically write one sector (512 bytes) so that the sector > contains either old or new content in case of crash." > > Well, maybe I am completly wrong but as far as I understand no disk > currently will provide such requirement. Disks can have (after halted > write): > - old data, > - new data, > - nothing (unreadable sector - result of not full write and disk > internal checksum failute for that sector, happens especially often if > you have frequent power outages). > I believe some vendors have such devices. Mikulas called them 'disk', but it's in fact a (disk(s), controler, ram, battery) Some controlers are even able to write into flash memory the un-written data when/if the battery/power is about to fail. When power goes up, controler can finaly do the writes on disks. > And possibly some broken drives may also return you something that they > think is good data but really is not (shouldn't happen since both disks > and cables should be protected by checksums, but hey... you can never be > absolutely sure especially on very big storages). > > So... isn't this making your filesystem a little flawed in design? Well... even RAM can fail :) In this case isnt linux flawed in design ? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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