jrb@wdl1.UUCP (jrb ) (08/03/84)
There should be no differences between the formats used by System V tar and Berkeley tar. The problem may be that System V tar always does a chown on each file to the UID that is stored on the tape. If it comes from a different system, the UID on the tape is probably not your UID. This means that it can create directories that it cannot write in. Berkeley tar, however, leaves everything owned by you as default and you can use a flag to force the other behaviour. If you have source, there are two lines in System V tar which need to be changed (grep for chown in the source). I added a flag and put the two lines in if()s on that flag. If you don't have the source, a superuser can read in the tape. Very annoying. John R Blaker UUCP: ...!fortune!wdl1!jrb ARPA: jrb@FORD-WDL1 and blaker@FORD-WDL2
pedz@smu.UUCP (08/07/84)
#R:hudson:-26100:smu:18500018:000:508 smu!pedz Aug 7 11:03:00 1984 I am confused. We run 4.2 and we have recieved several 'tar' tapes from software vendors. So far, we have not had any trouble reading these tapes. If Berkley tar is different then is it only in the write? Or are you talking about the additional information which specify the owner and modes of directories. If so, this information can be left off with the "o" option. The documentation clearly says that this information makes former versions of tar barf. Could someone who knows please clear the air.
guy@rlgvax.UUCP (Guy Harris) (08/21/84)
Other than possibly a question of blocksize, the only difference between
the versions of "tar" is that the Berkeley version puts entries on the tape
with pathnames ending in "/" to represent directories, so that 1) empty
directories can be put on a tape and made when the tape is read in and 2)
the owner and mode of directories is recorded on the tape. Other versions
of "tar" seem to complain when they see these entries, but just pass them over
and read the tape successfully anyway (without creating empty directories
or setting the owner or mode of non-empty directories created). 4.2BSD's
"tar" also puts special entries for symbolic links which other versions may
choke on. I've moved "tar" files between a 4.1c machine and a System III
machine (not tapes, because the 4.1c VAX uses 9-track tapes and the System
III micro uses cartridge tapes) with no problems other than occasional
complaints about "cannot create /usr/include/" and the like.
Repeat: there seems to be no real compatibility problem between 4.xBSD "tar"
and other versions of "tar". We now return you to your regularly scheduled
newsgroup.
Guy Harris
{seismo,ihnp4,allegra}!rlgvax!guy