On Thu, 12 Jun 2003, Jim Sibley wrote: > >File open-to-close doesn't > >sound like a very useful paradigm (but I don't know how Linux applications > >use tape drives) and I don't know if one part of Linux can open a tape > >file (tape management system, just to lock the drive and to request a tape > >mount) and another part of Linux subsequently > >opening-writing/reading-closing the same tape so that the drive is not > >unassigned until the tape management system closes the tape file. > > The implementation is what you would expect for a shared printer, a write > only device - during write, the device is dedicated and after the write, > the "data" is no longer available. > > The assign is done at open/close time, I suspect if one applicaiton assigns > the drive and leaves it assigned, then another application uses the drive, > then the the assign would be dropped after the second app closes the file. > > As implemented, is dangerous for shared tape, as it does not allow time for > operator intervention (loading/unloading the tape) before it is used by > another hosts, and 2) two hosts could rewind and/or record to the same tape > without knowing it. > > For example, tar is an applicaiton that can write to the tape directly and > read it back. > > tar -cvpi -f /dev/ntibm0 > > some time later (during this time, another system could do a > similar function) > > tar -xzpi -f /dev/ntibm0 results could be unpredictable or you > might get someone elses data!
That will _never_ work, even without another macine stuffing you up!! -- Cheers John. Join the "Linux Support by Small Businesses" list at http://mail.computerdatasafe.com.au/mailman/listinfo/lssb
