On Wed, Jun 09, 2004 at 05:34:03PM +0100, Steve McIntyre wrote: > Unfortunately, I don't see us (quite) getting that far. To generate the > md5 of the full image file (which is kind of useful), we need to read all > of the data through anyway. You can't simply lump together multiple md5 > chunks.
Ah - indeed, you're right. :-/ Hmmm. If the ability to create images this fast turns out to be a "must-have" feature one day, the template format could be changed: Either the image md5sum field could be left at zero to indicate "no md5sum available", or we could switch over to using what I call a "64 bit rsync sum" - a (cryptographically weak) checksum which allows "lumping together", already used internally by jigdo. > >Richard: I remember that you were about to put out a new version of > >jigdo that could help in this, how is this going? > > That's a bug to do with large file support in libstdc++ IIRC? I've > noticed the problem myself with large jigdo images. I'm just testing JTE > v1.1 right now to make sure I don't have similar issues. There *is* currently a problem with big files for gcc 3.x, x<4. However, the issue Manty was referring to is something else: Currently, the algorithm which searches for matching files inside the image sometimes has to discard prospective matches in order to avoid becoming too slow (ie not O(n²) instead of O(n) time). I have an idea for a way to improve the accuracy, which should result in a smaller template size because more files are found in the image. > Absolutely. It'd be great to be able to get _lots_ of jigdo files created > for all the different options including multiple variants of CD and > different DVDs. There are still some more optimisations that should be > possible in the image-building stages; at the moment we end up md5summing > the entirety of the data on each disk several times, and that's a little > bit wasteful. If you're talking about the md5sums.txt files on the CDs, note that you can take advantage of jigdo-file's cache when creating them: jigdo-file md5sum --cache=x.db --hex FILES... Cheers, Richard -- __ _ |_) /| Richard Atterer | GnuPG key: | \/¯| http://atterer.net | 0x888354F7 ¯ '` ¯ -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
