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Newsgroups: comp.os.386bsd.bugs Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!cs.utexas.edu!geraldo.cc.utexas.edu!portal.austin.ibm.com!awdprime.austin.ibm.com!fredriks From: fredriks@austin.ibm.com (Lars Fredriksen) Subject: Re: Help with julian's tape driver? Originator: @worf.cet.austin.ibm.com Sender: news@austin.ibm.com (News id) Message-ID: <C4npw1.1G35@austin.ibm.com> Date: Mon, 29 Mar 1993 15:33:36 GMT References: <1p0ntmINNjd1@ftp.UU.NET> Organization: IBM Austin Lines: 44 Hi, I am working on an enhancement to Julians st driver. The Tandberg drives insists on returning page00 upon a mode sense and also insist on getting page00 back upon a mode select. In addition it insist that you tell it what blocksize to use. The number is always 512, even if you are using the device as a variable blocksize device. The errors you are seeing is the mode sense/mode select stuff. The other problem with this drive that you will run into is that you will not be able to read fixed blocksize tapes with Julians driver (provided you got around the first problem). My driver is also trying to address this. I have a version that will work, and that uses minor numbers for the fixed blocksize functionallity. The problem with this is that you now have 32 minor numbers per tape device. The approach I am now taking is to use ioctl to set the fixed/variable blocksize behavior of the device. This means adding an IOCTL in /usr/include mtio.h, and adding functionality to mt to allow you to change this. I am debating if to take Nates suggestion an call the enhanced mt mtcontrol or some such thing, to try to avoid changing standard 4.3 BSD stuff. Since I have to change mtio.h as well I am not sure that this approach makes much sense. The other approach I can do is to introduce another header file. Lets say you create /usr/include/sys/scsi, create a file called st_ioctl.h (or whatever), then have mtcontrol use that. This way we don't mess with any of the 4.3 stuff, on the otherhand, we have now created something completely unique to 386BSD. I don't know which is the preffered method. I am open to suggestions on this one. Hope this rambeling helps. Lars -- Regards, ----------------------------------------------------------------------------