Friday, October 8, 2010

Necessity, Mother of Learning Zsync

I don't need to invent, just learn! My recent Kubuntu update from Lucid to Maverick RC broke YouTube. Actually, it broke my ATI graphics card driver, and the cure, as Jussi told me, is to re-install Maverick.

I have the alpha ISO on my hard drive, and slow as my Internet connection is here sometimes, I really didn't want to download essentially the same file AGAIN. Zsync to the rescue! As explained here,, if you use zsync on a ISO CDimage, you will get only the parts you need, not what you already have. So, I downloaded zsync, and did the command
You will need to replace the cdimage URL to the one you want, of course! Rather than taking over 3 hours, as it did to download the alpha, it took about ten minutes!

This is a wonderful tool for ISO testers to use, since you will not have to constantly download almost identical files. *Learned another tip about zsync from MJEvans at today's Maverick Release Party. Change the name of your old file to be identical to that of the new file before starting the process, and it will happen without any need to add additional filenames to the command line. Clever! Thank you Michael!

In Kubuntu, there is a magic program called usb-creator-kde. After the ISO is written to my little USB drive, all that remains is backing up my home partition -- just in case! And then re-installing Maverick Meerkat. I'll update this if anymore learning takes place!

Update: The download and write processes described above both went perfectly. However, the daily file I chose to install was NOT a perfect fit for my equipment, and I made a bad choice, in retrospect, in choosing to attempt a fresh install when I did. More details in another post.


  1. I use dl-ubuntu-test-iso from the ubuntu-qa-tools package (it uses zsync itself and I don't need to remember URLs).

  2. zsync is great when it works.

    I had downloaded a post-RC maverick-desktop-amd64.iso , so I renamed it kubuntu-10.10-desktop-amd64.iso and attempted zsync. It read the seed OK, let me know "Target 91.2% complete.", starting "downloading from REMOTE_URL", but then "failed to retrieve from kubuntu-10.10-desktop-amd64.iso

  3. very nice app!! saved me from downloading 35% of the regular natty-desktop-amd64 iso.
    what i did is renamed my previous kubuntu-10.10-desktop-amd64 iso to natty-desktop-amd64.iso, placed it into my home directory and run from terminal:
    zsync did a check at first and then started downloading the new iso from 35%. i have 1 MB conncetion and to me this is a very big time save!!!
    thanckyou for the howto!!!