On Wed, Jul 13, 2005 at 09:31:26AM +0200, Raphael Hertzog wrote: >Le mardi 12 juillet 2005 ? 19:08 +0200, Robert Lemmen a ?crit : >> > [...] once the tree gets to within a small >> > margin of the target, we can start running mkisofs -print-size to >> > check exactly how large the resulting image would be. It will even >> >> is this really necessary? can't we somehow determine how much will fit >> on the cd without doing this? > >To calculate the exact size of the image, you must have knowledge of >ISO-9660 and mkisofs has this knowledge. So it looks logical to rely on >it rather than reinvent the wheel. > >The image is by definition larger than the sum of the file size. You >have space lost for the filesystem meta-data and also because of the way >how data is stored (fixed-size blocks, ...). Yes, exactly. We can do quick-and-dirty size estimation as we copy files in, but the only way to know _exactly_ how big the image will be is to use mkisofs. Hence the "within a small margin" above. I'm hoping we can guesstimate sizes reasonably well up to ~95% of the target size, and go for the slower option from there: * Dump stanzas into the Packages/Source file and compress them * Update Release file * Fill in any last files * Run mkisofs --print-size The plan will then be to fill the discs as much as possible. In fact, the best way might even be to go 1 package/source file too far, then roll back. -- Steve McIntyre, Cambridge, UK. email@example.com You raise the blade, you make the change... You re-arrange me 'til I'm sane...
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