obscurity

aglew at ccvaxa.UUCP aglew at ccvaxa.UUCP
Thu Mar 13 17:04:00 AEST 1986


>/* Written  3:43 pm  Mar  5, 1986 by seifert at hammer.UUCP  */
>In article <464 at polaris.UUCP> herbie at polaris.UUCP (Herb Chong) writes:
>> the fragility of the filesystem implementation is not so great (having
>> recently patched some filesystems where the free-list was being
>> scribbled on by the hardware).
>The hardware screws up and scribbles on the disk and you're complaining
>about the software?  Perhaps you should be looking at replicated
>hardware.

Don't be so quick to lay all the onus for reliable filesystems on hardware.
Xerox had a system where both cooperated to make a more robust system:
disk blocks, in addition to being marked with track number and sector number,
were marked with file (inode) number, and logical sector number in that
file. Since these marks were part of the block header and not the data,
they were less likely to be scribbled in error.

Unfortunately, nobody except Xerox makes home-brew disk controllers. Sigh.



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