Thursday, January 25, 2007

4GB download

Knoppix has just released the latest 5.1.1 Live CD and Live DVD this month. I was so keen to download the Live DVD to try out the 3D desktop (boot with: knoppix desktop=beryl).

The Live DVD is 4.0GB in size and it may take me hours/days to download if I were to use my home 1.5Kbps ADSL connection. Worse still, all the mirror sites do not support "Accept-range" request. Of course, I do not want to power on my home notebook for hours/days to do that, it is not going to do any good to it. Instead, I remote login to one of my office Solaris boxes and do the download in the background. All I have to do now is to wait till the download complete. In order to ensure the download continue to work after you logoff, you need to do this
nohup wget http://somemirrorsite/location-of-the-live-dvd-iso > /dev/null 2>&1 &
nohup is to tell the system not to hang up

After the download is completed, I verified the download with md5 (in Solaris, it is "digest -a md5 the-iso-file"). So far so good, no hicup.

However, when I tried to ftp the file from within Cygwin in Windows XP to another PC, the transfer seeems to hang at the file size of 2GB. This may be the limit imposed in the older file systems, 2^31 bytes ??

I am not sure, but I need to get the 4GB out from the Solaris to my PC so that I can burn it in DVD. How ? Thanks to UNIX, "split" comes to the rescue. If you run "split -b 1024m the-iso-file", you are spliting the file to a chunk of 1024 MB or 1GB of size. FTP 1GB files (the file names are xaa, xab, xac, and so on, by default) have no issue at all.

In the PC running Cygwin, I simply "cat xa? > the-iso-file" to concatenate all these files to form my ISO image (In DOS, "copy /b file1 + file2 + file3 + file4 + file5 file.iso"). I am also able to verify the MD5 checksum in Cygwin with md5sum the-iso-file

Now I have the latest Knoppix Live DVD with me. Hip hip hooray !

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Blogger Ah Choo said...

Now I know why you want the Live CD.
You get me interested too.

10:00 PM  

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