reid@su-glacier.ARPA (Brian Reid) (03/20/85)
Can SYS-V systems with cpio reliably read tar tapes produced by 4.2BSD? If not, is there an interchange format besides dd that is guaranteed to be universally readable by any Unix system with a suitable tape drive? Brian Reid decwrl!glacier!reid Stanford reid@SU-Glacier.ARPA
gwyn@BRL-VLD.ARPA (VLD/VMB) (03/20/85)
UNIX System V has a "tar" and a "cpio"; 4.2BSD just has "tar". The "tar"s aren't completely compatible but for inter-UNIX tape transfer that's probably your best bet.
root@bu-cs.UUCP (Barry Shein) (03/21/85)
We have a 3B5 running SYSV and and 4.2bsd VAXen. Yes, tar is compatible between these two (in spite of things that *might* have broken it.) Unfortunately, it seems that our SYSV tar won't read tar tapes created on 4.2bsd with a blocking factor >10 so be warned. (I also swear that twice when I was writing tar tapes to our TU78 on our VAX with blocking factor of one it tripped the circuit breaker in the tape drive!!) As for cpio, all I know is that the standard cpio format VAX SYSV source release from AT&T would *not* read off on our 3B5, no matter what combination of byte/word swap etc (-B) flags was tried. Not having cpio (it was on the #@!#@ tape!) I wrote a trivial program I call 'cpi' that will suck off a range of files from a cpio tape and create all necessary directories etc as expected (won't write a tape.) If anyone wants it it's a hack (only needed it till I got cpio.c off) but hey, it's <100 lines of C, you can clean it up yourself, and it works, just ask. -Barry Shein, Boston University
rrw@ccice2.UUCP (Rick Wessman) (03/21/85)
> UNIX System V has a "tar" and a "cpio"; > 4.2BSD just has "tar". The "tar"s aren't completely > compatible but for inter-UNIX tape transfer that's > probably your best bet. As far using "tar" goes, there should be no problem. We transfer files all the time between our sys3/sys5 compatible machine and our 4.2 Vax. The incompatibility arises when an option unique to one version is used. Rick
todd@bu-cs.UUCP (Todd Cooper) (03/22/85)
I had some problems, but it seems to be a "bit" compatible, most of my problems were file system differences. -- --------------------------- Todd Cooper (617) 424-9018 UUCP: ...!harvard!bu-cs!todd ARPA: todd%bu-cs.csnet@csnet-relay.arpa
ed@mtxinu.UUCP (Ed Gould) (03/26/85)
> Can SYS-V systems with cpio reliably read tar tapes produced by 4.2BSD? > If not, is there an interchange format besides dd that is guaranteed to > be universally readable by any Unix system with a suitable tape drive? > Brian Reid decwrl!glacier!reid > Stanford reid@SU-Glacier.ARPA System V machines that *have* tar can read 4.2 tapes, but not all of them have tar. Right now, there is no reliable interchange other than the brute force use off dd and human intervention. The /usr/group standards comittee (now an IEEE group) has suggested that tar be adopted as the standard interchange. If this actually becomes the standard, then I assume (from all of their recent hype about being standard) that they'll add tar back into SysV. -- Ed Gould mt Xinu, 739 Allston Way, Berkeley, CA 94710 USA {ucbvax,decvax}!mtxinu!ed +1 415 644 0146
root%bostonu.csnet@csnet-relay.arpa (BostonU SysMgr) (03/27/85)
Sorry, but I keep getting these mailings from people that *they* were able to read/write a cpio tape between UNIXes [usually saying that they had to use some flag or another to create the tape.] The *point* is not whether or not one can create a tape, given the correct parameters (eg. -c) that is portable. The point was that I was unable to read the AT&T SYSV VAX source distribution tape on my 3B5 no matter what switches I fed it. Obviously I had no opportunity to specify how they wrote the tape. The only problem I have had with tar is large blocks, hopefully this is the kind of knowledge that is easier to disseminate (don't write tar tapes with blocking factors bigger than about 5). The various word/byte swap problems on the cpio tapes (which the switches that claim to handle do !not!) are quite obscure to 'users'. Sum: If a user came to me and said "I need to send a tape of files to a friend on some UNIX systems what should I use?" I would recommend: cd directory tar cbf 5 /dev/rmt0 . ! or whatever tape device and be about 99% sure my phone wouldn't ring again. I have no such confidence in cpio (anymore.) As a robustness note, even tho UCB puts directory names on the tape SYSV just grumbles and ignores and finishes fine. Conversely, given a tape to read on a new system I would budget more time if it were a cpio tape. -Barry Shein, Boston University
piet@mcvax.UUCP (Piet Beertema) (03/28/85)
>The only problem I have had with tar is large blocks
3B machines can't read tape blocks larger than 8K. So carefully choose the
blocking factor when making a tar taoe for such machines.
--
Piet Beertema, CWI, Amsterdam
...{seismo,okstate,garfield,decvax,philabs}!mcvax!pietguy@rlgvax.UUCP (Guy Harris) (04/01/85)
> System V machines that *have* tar can read 4.2 tapes, but not all of them > have tar. ... then I assume ... that they'll add tar back into SysV. The VAX distribution of System V Release 2, both Versions 1 and 2, comes with "tar". In fact, it has a new "-o" flag (conflicting with Berkeley's, alas) which tells "tar" not to give files to the owner from the tape. A damn good idea, considering user 45 at the site that made the tape might not be the same user as user 45 here... Guy Harris sun!guy (ignore all other addresses in this message)
clewis@mnetor.UUCP (Chris Lewis) (04/08/85)
I have found one incompatibility - Plexus machines output swapped bytes.
We received a Plexus-generated tar tape and had to do a dd swapb to be able
to read it. We complained to the originator (wasn't plexus) and they
said it was a natural consequence of byte order. That's crap - Our
Pyramid is backwards from a VAX and we don't have any problem. They
just never realized that the Plexus tar should swap bytes to remain
compatible with the rest of the world (I suspect that it was a wierd
tape driver/hardware configuration)
--
Chris Lewis, Motorola New Enterprises
UUCP: {allegra, linus, ihnp4}!utzoo!utcs!mnetor!clewis
BELL: (416)-475-1300 ext. 321wunder@wdl1.UUCP (04/11/85)
When moving files from 4.2 BSD to System V, you should also watch out for file names longer than 14 characters. Those can cause problems if the truncated version is not unique. These two will both end up in "verylongfilena": verylongfilename.c verylongfilename.h wunder
jsdy@hadron.UUCP (Joseph S. D. Yao) (04/11/85)
> ... As a robustness note, even tho UCB puts > directory names on the tape SYSV just grumbles and ignores and finishes > fine. Conversely, given a tape to read on a new system I would budget > more time if it were a cpio tape. If you're creating a 4BSD tar tape for a USG or unspecified UNIX system, you should use the 'o' keyletter. This says, omit those directories. Also, if you are using cpio on a 4.2+BSD system, you must beware of how it handles symbolic links (typically, incorrectly). We had one problem (which we can't duplicate) in which it changed the dates of the source files to something negative! The ctime() routine was unable to cope with this at all (*sigh*). Joe Yao hadron!jsdy@seismo.{ARPA,UUCP}
root@bu-cs.UUCP (Barry Shein) (04/16/85)
From: jsdy@hadron.UUCP (Joseph S. D. Yao) Newsgroups: net.unix-wizards Subject: Re: how universal is tar format? SYSV? >> ... As a robustness note, even tho UCB puts >> directory names on the tape SYSV just grumbles and ignores and finishes >> fine. Conversely, given a tape to read on a new system I would budget >> more time if it were a cpio tape. [Me, btw] >If you're creating a 4BSD tar tape for a USG or unspecified UNIX system, >you should use the 'o' keyletter. This says, omit those directories. > Joe Yao hadron!jsdy@seismo.{ARPA,UUCP} You are making the classic mistake, my original comments had more to do with randomly created tapes falling in your lap (ie. *I* didn't write them.) The whole point was mucho trouble with cpio tape in at least one case (argh!! don't respond with ways to write portable cpio tapes! this one was from AT&T, it was tooo late.) and very little trouble with tar tapes. If you have control you can write a portable EBCDIC tape with dd, as long as *you* read and *you* write it. -Barry Shein, Boston University
wcs@ho95b.UUCP (Bill Stewart) (04/19/85)
>You are making the classic mistake, my original comments had more >to do with randomly created tapes falling in your lap (ie. *I* >didn't write them.) The whole point was mucho trouble with cpio tape >in at least one case (argh!! don't respond with ways to write portable >cpio tapes! this one was from AT&T, it was tooo late.) and very little >trouble with tar tapes. If you have control you can write a portable >EBCDIC tape with dd, as long as *you* read and *you* write it. > -Barry Shein, Boston University We get lots of bizarre tapes; the EBCDIC ones are usually the easiest to read - most of them are 80-column, 1680-blocksize (or non-blocked). The tough ones are the 5-volume set, with a piece of duct tape numbered 1,2,3,4,or 5 as the only labeling. Of course it was binary, but we did have a nearly-unreadable photocopy of the first page of the printout, with some format info... "What's a Blocksize?" The critical part is getting the people to mark the tape reel with the format (NOOOO, that's a NON-labelled TAPE, with a labelled REEL, not...) --- Bill Stewart, AT&T Bell Labs, Holmdel NJ