Path: utzoo!utgpu!watmath!clyde!att!ucbvax!NUSVM.BITNET!GBOPOLY1 From: GBOPOLY1@NUSVM.BITNET (fclim) Newsgroups: comp.sys.apollo Subject: re: getting tar to do what it is told Message-ID: <8812030651.AA28193@umix.cc.umich.edu> Date: 3 Dec 88 06:52:44 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 47 X-Unparsable-Date: Sat, 03 Dec 88 14:03:08 SST tom cunningham asked how to use tar on cartridge tapes. the domain/ix 4.2bsd man page (section 4 on mtio) says that /dev/rct[8|12] has a block length of 512 bytes and the man page (section 1 on tar) says that (under the b option) the blocking factor on cartridge tape must be 1. therefore, you must do: % /com/rbak -dev ct -rewind % tar cvbf 1 /dev/rct8 .... note the b option must be given and the arguments 1 and /dev/rct8 must be in the same order as the b and f options. you may specify the default blocking factor of 20 only when you are using /dev/rmt[8|12]. ie % tar -cv .... % tar -cvb 20 ... are the same. the max arg to the b option on /dev/rmt[8|12] is 20. note that you need not rewind the mag-tape. but you must *always* issue % /com/rbak -dev c -rewind first before you use tar or dd(1) on the cart tape drive. sometimes, i make tapes in another way: % pdtar cvzf foo.pdtar.Z ... % /com/rbak -dev ct -rewind % /com/rwmt -dev ct -raw -unlab -write -rl 512 -bl 512 -rf f -f 1 foo.pdtar.Z this way, you may have a few tar files on tape by changing the -f 1 option to /com/rwmt to -f 2, etc. eg: % /com/rwmt -dev c -raw -unlab -w -rl 512 -bl 512 -rf f -f 2 bar.pdtar.Z puts bar.pdtar.Z after foo.pdtar.Z. When reading this tape on, say, a sun machine, one may use % tar -xvf /dev/rct0 where /dev/rct0 on a sun does not rewind when tar finished reading foo.pdtar.Z. to read bar.pdtar.Z on an apollo, do % /com/rwmt -dev c -raw -unlab -r -rl 512 -bf 1 -rf f -f 2 bar.pdtar.:z hope this helps. :-). fclim. fclim --- gbopoly1 % nusvm.bitnet @ cunyvm.cuny.edu computer centre singapore polytechnic dover road singapore 0513.