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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!munnari.oz.au!spool.mu.edu!agate!doc.ic.ac.uk!uknet!mcsun!sun4nl!star.cs.vu.nl!kjb From: kjb@cs.vu.nl (Kees J. Bot) Subject: Re: MT-02 Message-ID: <CCBC3L.HKB@cs.vu.nl> Sender: news@cs.vu.nl Organization: Fac. Wiskunde & Informatica, VU, Amsterdam References: <match.21.0@> <CC3zDw.Iu0@sugar.NeoSoft.COM> <3914@bigfoot.first.gmd.de> <CC9xB8.19E@sugar.NeoSoft.COM> Date: Wed, 25 Aug 1993 11:33:20 GMT Lines: 42 peter@NeoSoft.com (Peter da Silva) writes: > >In article <3914@bigfoot.first.gmd.de> ats@g386bsd.first.gmd.de (Andreas Schulz) writes: > >> This old SUN drives knows two modes, QIC24 >> and QIC11, and QIC11 maxes out at 30Mb. On the SUN, you reached the >> QIC11 mode with the normal st0/rst0 and the QIC24 mode with st8/rst8. >> I don't know, if the st driver on 386BSD/FreeBSD/NetBSD has anywhere >> a flag to switch between different modes. > >Well, if someone comes up with info on that I'd like to know about it. >I would have assumed it'd use the highest density the tape supported, >and the MT02 is documented as being able to read the tape density info. I am able to write 45Mb to a 45Mb tape on an old Emulex tape drive. It sits in an old Sun shoebox (of course) connected to a 1542B in a PC running Minix-386. I have written this tape in both QIC-24 and QIC-11 mode. In both cases 45Mb could be written, which is no surprise, because QIC-24 and QIC-11 only differ in the recording method, but are both 8000bpi (SCSI-2 standard table 9-22). The tape drive is by default in QIC-24 mode (density code 5). To read a QIC-11 tape you need to set it to density code 4. To read *or* write it density code 0x84 (vendor reserved) must be chosen. The Sun driver selects densities with a few bits in the minor device number (rst0, rst8, rst16, rst24), this requires a table in the driver indexed by the ID string of the tape. For Minix I have extended the SCSI driver and mt(1) command so that I can type 'mt mode 0x84' to set the density code. Now I don't need to recognize tape drives in the driver. Those old tapes do give out a lot of recoverable errors that need to be caught and ignored. The unit attention is the normal way for the device to tell that something has happened that should be investigated, like one Mr. Da Silva putting a tape in the drive. -- Kees J. Bot (kjb@cs.vu.nl) Systems Programmer, Vrije Universiteit Amsterdam