7. Errata

7.1. jigdo-easy

Jigdo-easy, by Anne Bezemer, is a fork of jigdo-lite which is portable to a wider range of systems, including Microsoft Windows, old SunOS, HP-UX and IRIX). It's also easier to use than jigdo-lite but because of changes made to Jigdo, will only work with Potato and Woody. Jigdo-easy will not be able to download Sarge and Sid. See Section 7.4 and Section 6.14.

7.2. More About Scan Sources

By now you know that when jigdo-lite asks for files to scan, you can use 3 sources:

• A mounted copy of an outdated CD or DVD that you wish to update.

• A loop-mounted copy of an outdated ISO image file on your hard drive.

• A loop-mounted copy of the temporary .iso.tmp file, when a previous jigdo-lite run aborted.

As Jens Seidel points out, there is another, rather crafty, source you should use for a scanning source: your apt cache. Apt uses the directory /var/cache/apt/archives for cache. There will be many Debian packages sitting in this directory, and they can be used for a scan source for jigdo-lite! So when you're asked for a directory to scan, by all means, use this directory too.

If you're editing the ~/.jigdo-lite file by hand, be aware that multiple scan directories are space separated, for example:

      scanMenu='/var/cache/apt/archives/ /cdrom/'
      

7.3. jigdo-file-cache.db

The cache contains the md5sums of files read when you supply a directory at the Files to scan: prompt. If you have jigdo-file scan the same directory a second time, the scan will be very fast.

This could be useful in the following case: rev0 gets updated to rev1. With the rev1 CD images, some packages may have been pushed from CD n to CD n+1, or vice versa. If you had a particularly slow link (e.g. modem), you'd try to avoid downloading these packages again. For this reason, when downloading the new version of CD n, you'd let jigdo-lite scan the three CDs n-1, n and n+1 (or even all 8 CDs if you want to be 100% sure).

If you have jigdo-lite scan the same CDs over and over again while updating each of the 8 CD images, the cache will prevent all the data on the CDs from being read multiple times.

The cache is much more important when generating jigdo files, because you don't want jigdo-file to read in your whole 50GB Debian mirror for every generated jigdo file.

7.4. Resources

This HOWTO is winding down to a close, but I thought I'd leave you with a few links and references to learn more about the jigdo tools and how they work.