corrupted x32 Fedora 14 DVD

Robert G. (Doc) Savage dsavage at peaknet.net
Tue Nov 9 22:14:42 UTC 2010


On Tue, 2010-11-09 at 17:58 -0300, Fernando Cassia wrote:
> Yes, FTP would be the better choice to ensure file integrity. A decade
> ago I was a fundamentalist and used to write every time I saw a large
> program file linked on web servers over HTTP telling them to "create a
> FTP server" and that "the ftp protocol exists for a reason".

Fernando,

Yes and no. The integrity of FTP transmissions are based solely on TCP
checksums and retransmissions. Rsync and torrent are also TCP protocols,
but they have powerful integrity-tracking mechanisms of their own in
addition to TCP's. If you have access to a remote rsync server, a local
rsync client may be your best choice to guarantee perfect delivery. It
will repair on-the-fly any possibly-corrupted iso file you already have
in far less time than a ftp retransmisison. Suggest moving the DVD iso
file you have to your Downloads directory and trying the following
(note: some rsync sites do not support the -c option):

        $ time rsync -acvxzHP --no-motd rsync://rsync.gtlib.gatech.edu/fedora-linux-releases/14/Fedora/i386/iso/Fedora-14-i386-DVD.iso ~/Downloads/
        
        # where the rsync man page defines the dash options as:
        #       -a      archive mode; same as -rlptgoD (no -H)
        #               -r      recurse into directories
        #               -l      copy symlinks as symlinks
        #               -p      preserve permissions
        #               -t      preserve modification times
        #               -g      preserve group
        #               -o      preserve owner (super-user only)
        #               -D      same as --devices --specials
        #                       --devices       preserve device files (super-user only)
        #                       --specials      preserve special files
        #       -c      skip based on checksum, not mod-time & size
        #       -v      increase verbosity
        #       -x      don’t cross filesystem boundaries
        #       -z      compress file data during the transfer
        #       -H      preserve hard links
        #       -P      same as --partial --progress
        #               --partial       keep partially transferred files
        #               --progress      show progress during transfer
        #       --no-motd       suppress daemon-mode MOTD (see caveat)

I have fast service (12 Mbps) and get the following result for an
already-perfect DVD iso file:

        receiving file list ... 
        1 file to consider
        
        sent 151 bytes  received 1063 bytes  5.07 bytes/sec
        total size is 3561752576  speedup is 2933898.33
        
        real    3m59.060s
        user    0m12.592s
        sys     0m3.648s

Hope this helps.

--Doc Savage
  Fairview Heights, IL



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