a way to correct a corrupt F8 iso file ?

[Cameron Simpson]

On 19Nov2007 07:09, John Summerfield <debian at herakles.homelinux.org> wrote:
| hicham wrote:
|>  I've downloaded a F8 dvd iso file, but after cheking the sha1sum, it
|> gives me the wrong series of letters and numbers :(
|> I was wondering if there is a tool that correct the iso file without
|> having to download everything from scratch
|
| Find an rsync mirror.
|
| Do not use --checksum, the host will be upset with you. The time I needed 
| to do it (and the time I was told not to --checksum), rsync wasn't doing 
| anything, I think because the local time and size matched. What eventually 
| worked was copying the image with dd, using blocksize and count to copy 1k 
| less than the actual size.

It would have been faster to just touch(1) the .iso file. Then the mtime
wouldn't match.

| I then used rsync to update that and it was all 
| over almost instantly.
| I don't understand _how_ it did it, but I _know_ it's magic.

It will have used checksums for the portion you had, refetching the
chunks where the checksums didn't match and of course the missing tail
of the file.

The reason to avoid --checksum (the option) is that it forces checksums
even on files where the size and mtime _do_ match, wasting much resource
if you're updating a directory tree with few changes.

But for incomplete (or not same-size+mtime ==> presuming ok) files,
checksums are used.

But the basic premise is right - find an rsync mirror. Do not use the
--checksum option (for directory trees is it wasteful and for a single
damaged file like yours it will be redundant).

Cheers,
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

When we say we want sensitive men, we mean 'thoughtful and considerate', not
'easily wounded'.       - Susie, friend of Julie Wright <julie at pell.com>