cs00chs@unccvax.uncc.edu (charles spell) (08/22/90)
I noticed that cpio produces much larger archive files than tar.
What would be some advantages of using cpio instead of tar?
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In article <2627@unccvax.uncc.edu> cs00chs@unccvax.uncc.edu (charles spell) writes: >I noticed that cpio produces much larger archive files than tar. > >What would be some advantages of using cpio instead of tar? That's strange. Tar uses very inefficient and large headers. While archiving half of the command sources, tar produced a file of 627KB, but the cpio generated file was 584KB. No so much smaller, but at least not larger than the tar file! The commands, which I archived, were rather large files, so I tried to archive all the C sources in lib/other. Tar produced a file of 152KB, cpio a file of 112KB. The directory contained 58 files, most of which were under 1KB. I used `ls *.c | cpio -ocvB >lib.cpio' to generate the cpio file. When not using the `c' and the `B' options, the cpio file was only 107KB. I don't understand how you got a cpio file, that was significantly larger than the corresponding tar file. What sort of files did you archive? Adrie Koolen (adrie@ica.philips.nl) Philips Innovation Centre Aachen
andreas@nixhhs.UUCP (Andreas Wettengel) (08/28/90)
In article <653@philica.ica.philips.nl> adrie@beitel.ica.philips.nl (Adrie Koolen) writes: >In article <2627@unccvax.uncc.edu> cs00chs@unccvax.uncc.edu (charles spell) writes: >>I noticed that cpio produces much larger archive files than tar. >> >>What would be some advantages of using cpio instead of tar? > >That's strange. Tar uses very inefficient and large headers. Both of you are correct (:-). Cpio is inefficient when encountering links. Each file is put on the archive, regardless if it has already been put there as another (linked) file. When files are extracted, links are recognized. Tar recognizes links at the time the archive is produced. > When not using the `c' and the `B' options, the cpio file was only >107KB. The 'B' option only affects the 'write' command; no padding is done except on the last block (512 vs. 5120 bytes). -- Andreas Wettengel | Nixdorf Computer AG Tel. +49 40/6371-2423 | Ueberseering 33 (...uunet!)unido!nixhhs!andreas | 2000 Hamburg 60 NERV: nixhhs!andreas.eunet | West Germany