Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!mcsun!unido!rzsun2.informatik.uni-hamburg.de!bosun1!weigele From: weigele@bosun1.informatik.uni-hamburg.de (Martin Weigele) Newsgroups: comp.sys.next Subject: NeXT answer to tape drive problems (was: Sun tape streamer (was: silly cables) Message-ID: Date: 19 Feb 91 13:14:48 GMT References: <1991Feb14.173537.16342@nntp-server.caltech.edu> Sender: news@informatik.uni-hamburg.de (Mr. News) Distribution: comp Organization: University of Hamburg, FRG Lines: 33 weigele@bosun1.informatik.uni-hamburg.de (Martin Weigele) writes: [About SUN OEM Viper 150 streamer] >The streamer tape is successfully SCSI-recognized during boot, and it is >possible to "mt -f /dev/nrst0 " as well as with /dev/rst0. >This seems to work. However, tar-ing or dd-ing from or to tapes results >in "i/o errors" (I tried with more then one tape). Here's the comment from my dealer who forwarded the information from NeXT: "Hier die Antwort von NeXT: You need to use the MTIOFIXBLK ioctl to set fixed block mode on the device access. Otherwise you should ensure that the transfers are a multiple of 512 bytes, by using the b option to tar. If you do not do this, the access will fail with a SCSI error. This is because the Viper 150 supports only fixed block size accesses. The 2.0 device driver assumes devices can handle variable block sizes. Hence any drive that supports variable size blocks will work automatically with the NeXT at 2.0." >I wonder if there is any "configuration trick". Unfortunately the otherwise >detailed documentation (about ODs and Exabyte drives) does give very >little documentation about /dev/rst0 type streamers. Actually, once you know you need to look up ioctl the extended release documentation has this in the manual pages. Unfortunately, I didn't have the time to try this out yet because I need to borrow the tape drive, but maybe someone else is happy with this info. One solution might be to adapt GNU tar (or maybe this has been done already. We don't have the latest version, probably). Or does anyone know about tape drives which support variable size blocks? Anyone? Martin