What is the best way to obtain an exact copy download?-->wrong md5 after downloading 5.3dsc1,2=(

[cape canaveral]

On Mon, 8 Nov 2004 06:03:15 -0800, cape canaveral <somniosus at gmail.com> wrote:
> 
> 
> On Mon, 8 Nov 2004 12:02:13 +0200, Giorgos Keramidas
> 
> <keramida at ceid.upatras.gr> wrote:
> > On 2004-11-08 00:41, Mark Jayson Alvarez <jay2xra at yahoo.com> wrote:
> > > Good day!
> > >   After downloading disc1 and disc2 of freebsd 5.3, my boss told me to
> > > verify the download using md5.
> >
> > Good thinking.
> >
> > > And to my surprise, none of those two iso's have the same md5 as that
> > > of the md5 written in CHECKSUM.md5.
> >
> > Some times, if you start downloading an ISO image while it is still being
> > uploaded to the ftp-master server or while a mirror still fetches the same ISO
> > image from ftp-master, what you get is an incomplete download.  Try comparing
> > the sizes of the files on the remote server after a while.  If it has changed,
> > the ISO iamge is still being uploaded to the FTP server; wait a bit and retry.
> >
> >
> >
> > > Question:
> > >    On the middle of my download, how will I know if I'm still downloading
> > > the correct file, that no packet is being dropped and that I will end up in
> > > a perfect mirror file download? Do you know any downloading tool that will
> > > do just like this? Earlier, I just used the konqueror when I downloaded
> > > those ISO's. Is it really that hard to download? We're using E1 modems and
> > > our internet connection is quite fast. I'm just thinking, we are still lucky
> > > because of this. But how about those people with low bandwidth internet
> > > connection?  Do they have a choice?
> >
> > All this should be handled gracefully by the TCP network.  AFAIK, there is no
> > easy way to verify half of a file while it's still being downloaded over FTP.
> >
> >
> >
> > _______________________________________________
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> > http://lists.freebsd.org/mailman/listinfo/freebsd-questions
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> >
> 
> One optoin is to use the Bittorrent download - it will do hash checks
> of each piece and re-download any which fail.
> 
> Another option (if you do not want to re-download both CDs) is to have
> someone with known good copies help you recover the existing files.
> Two utilities which can do this are zidrav and quickpar.  I doubt very
> much that more than 1MB of parity data would be required to repair
> these cd images; they are probably off by only a few bytes.
> 
> -Aaron
> 

Actually, I just remembered a trick I do sometimes: grab the .torrent
and start downloading, then stop.  The point is to just get the
locations of the files as created by the torrent.  Take the existing
iso images and copy them over the ones that the torrent has created. 
Then restart the torrent, it will do a check of the files and then
(hopefully) redownload whichever parts are corrupt.