Re: the " 'official' point of view" expressed by kernelnewbies.orgregarding reiser4 inclusion

From: Edward Shishkin
Date: Fri Aug 04 2006 - 13:02:22 EST

Hans Reiser wrote:
Edward Shishkin wrote:

Matthias Andree wrote:

On Tue, 01 Aug 2006, Hans Reiser wrote:

You will want to try our compression plugin, it has an ecc for every

What kind of forward error correction would that be,

Actually we use checksums, not ECC. If checksum is wrong, then run
fsck - it will remove the whole disk cluster, that represent 64K of

How about we switch to ecc, which would help with bit rot not sector loss?

Interesting aspect.

Yes, we can implement ECC as a special crypto transform that inflates
data. As I mentioned earlier, it is possible via translation of key
offsets with scale factor > 1.

Of course, it is better then nothing, but anyway meta-data remains
ecc-unprotected, and, hence, robustness is not increased..


and how much and

what failure patterns can it correct? URL suffices.

Checksum is checked before unsafe decompression (when trying to
decompress incorrect data can lead to fatal things). It can be
broken because of many reasons. The main one is tree corruption
(for example, when disk cluster became incomplete - ECC can not
help here). Perhaps such checksumming is also useful for other
things, I didnt classify the patterns..


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