18 May
2005
18 May
'05
11:45 a.m.
>>>> "Jim" == Jim Leonard
<trixter at oldskool.org> writes:
Jim> Jules Richardson wrote:
>> The problem I see with zip is the single table
of contents at the
>> end. Did you try corrupting THAT with a hex editor?
> Ahh, no not at the time. I've just tried it now though and it
> seems remarkably good at recovering from corruption in the TOC
> area. Actually, looking at the zip file it appears to have
> something resembling a file header before each file in the archive
> as well as the TOC at the end.
Jim> As long as we're talking about fault-tolerant archives, neither
Jim> TAR nor ZIP are acceptable. For years I've used RAR (WinRAR for
Jim> windows, RAR and RAR32 for DOS) which has "recovery record"
Jim> support (parity info). ...
If you want fault tolerance, it may be a good idea to learn the topic
of "erasure codes" -- a general concept for way to split data into N+K
pieces such that you can reconstruct the data from any N pieces (for N
and K chosen to be whatever you wish).
VMS also implemented the XOR thing you mentioned in the BACKUP
utility (as did RSTS, of course -- since it supports the same
format).
paul