12 Aug
2004
12 Aug
'04
1:48 p.m.
On Thu, 12 Aug 2004, Antonio Carlini wrote:
My reason for mandating a CRC would be that otherwise
you have no way of knowing that an error has occurred.
An unreliable archive format is a terrible thing to
foist on future generations: they should be able to
know whether the data has been correctly preserved
or not. Without a CRC (or similar mechanism) you have
no guarantee of that. One of the advantages of storing
zip (or rar or whatever) archives on CD is that if
you can copy it off and unzip it, you can reasonably
expect the end result to be an accurate reproduction of
the original.
The problem with ZIP for example is that if the archive is considerably
corrupted you don't get anything. I'd rather have an archive with some
corrupt data than a ZIP file that won't unzip :(
But anyway, again, point taken (again).
Error correction is just an added bonus and may or
may
not be worth the additional effort. Perhaps optional
additional redundancy (OpenVMS BACKUP will write a
parity block of data for every N blocks of real
data, PAR implements "RAID for newsgroups").
It should be possible to add error correcting data to the archive.
--
Sellam Ismail Vintage Computer Festival
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