Date: Sat, 25 Jan 1997 16:59:49 +0100 From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-scsi@FreeBSD.org (FreeBSD SCSI list) Cc: chris@bb.cc.wa.us (Chris Coleman) Subject: Re: Tape Backup Drive Not working. Message-ID: <Mutt.19970125165949.j@uriah.heep.sax.de> In-Reply-To: <199701251540.PAA16318@deacon.cogsci.ed.ac.uk>; from Richard Tobin on Jan 25, 1997 15:40:40 %2B0000 References: <199701251540.PAA16318@deacon.cogsci.ed.ac.uk>
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As Richard Tobin wrote: > Essentially all that was required was setting the PF bit in mode > select, but there's no reason to suppose that Conner's SCSI > implementation will have the same quirks as HP's. Hmm. I wonder if there's any reason to _not_ set the PF bit by default? Julian? Justin? Are there any tape drives known to choke on this? For the curious, here's the patch (offhand, untested). I'd vote that, if we need it at all, we should unset the bit based on some drive's quirks, but turn it on by default (in the assumption that most drives adhere to SCSI-2). I'd be particularly interested in getting feedback from people owning an old drive that doesn't claim to be SCSI-2 (like an old Archive Viper 150 or Wangtek 5150ES). Index: scsi/st.c =================================================================== RCS file: /home/ncvs/src/sys/scsi/st.c,v retrieving revision 1.74 diff -u -u -r1.74 st.c --- st.c 1997/01/14 06:54:22 1.74 +++ st.c 1997/01/25 15:56:34 @@ -1405,6 +1405,7 @@ bzero(&dat, dat_len); bzero(&scsi_cmd, sizeof(scsi_cmd)); scsi_cmd.op_code = MODE_SELECT; + scsi_cmd.byte2 |= SMS_PF; scsi_cmd.length = dat_len; dat.header.blk_desc_len = sizeof(struct blk_desc); dat.header.dev_spec |= SMH_DSP_BUFF_MODE_ON; -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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