On Wed, Sep 22, 2004 at 06:16:14PM -0500, Christopher J. Bottaro wrote: > where can i get documentation on the header.info format? where can i get > more detailed information on the inner workings of yum beyond what is > covered by http://linux.duke.edu/projects/yum/howitworks.ptml. how does it > know what is installed on your system vs what is available in the repos vs > what you have but needs to be updated, etc? the stuff stored > in /var/cache/yum is only the package info for the repositories, right? > (i.e. the info in the caches tell nothing about your actual system)? yum > then runs rpm to query your actual system then it compares that output to > what it has in the caches...? * if you are planning on working on yum stuff (whether you ever intend to contribute it or not), you should do new develpment on the cvs branch, which is available as 2.1.x. In that, the header.info and header files are no longer used. They're replaced by a series of xml files that contains the necessary data. * there is no real documentation of the inner workings of yum other than the source code itself. * the information about what's available in the repos is contained in header.info and header files for the old style, and in the xml files for the new style. This info is on the repo and is fetched (what's needed and new, anyway) each time yum runs. * yum can tell what's on your system because rpm keeps a database with all that information in it. * yum does not run the rpm executable, but rather uses the rpm-python bindings which allow direct (and cleaner) access to the information. This is how the rpmdb is access, how packages are installed, etc. If you have one or two small followup questions, feel free to ask them. Otherwise, you should simply turn to the source code. I hope that helps. -Michael -- Michael D. Stenner mstenner@xxxxxxxxxxxxxxx ECE Department, the University of Arizona 520-626-1619 1230 E. Speedway Blvd., Tucson, AZ 85721-0104 ECE 524G
