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

From: Edward Shishkin
Date: Thu Aug 03 2006 - 11:43:02 EST


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 64k....


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
data.


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..

Edward.
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