*BSD News Article 2361


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Newsgroups: comp.unix.bsd
Path: sserve!manuel!munnari.oz.au!uunet!mcsun!sunic!aun.uninett.no!nuug!nntp.uio.no!bootes.sds.no!toreh
From: toreh@bootes.sds.no (Tore Haraldsen)
Subject: 386BSD & SCSI - Multiple file tapes
Message-ID: <1992Jul23.130323.4617@ulrik.uio.no>
Sender: news@ulrik.uio.no (Mr News)
Nntp-Posting-Host: 192.68.77.217
Organization: Statens Datasentral A/S, SDS, Norway
References: <1992Jul23.125510.4250@ulrik.uio.no>
Date: Thu, 23 Jul 1992 13:03:23 GMT
Lines: 23

It IS possible to read multiple file tapes, if you do the following
modifications to i386/isa/as.c:

1) Change the definition of dev_rewind macro to use a mask outside the
   other fields used by the scsi driver. Using the partition field for
   no-rewind flags will not work, due to imprecise coding elsewhere in
   the driver. Use 0100 for instance. Make a new kernel.

2) Create a device with this capability:
		mknod /dev/nras2a c 13 80

   The last number, 80 = 16 (=minor device number for as2) + 64
   (decimal representation of 0100).

3) When using the tape device for the first time, do some sort of dummy
   access to it: tar a cpio tape or vice versa. There seems to be some
   sort of race condition otherwise that will otherwise give you the
   unwanted rewind.

4) Good luck. This is just a hack, somebody compentent will have to
   rewrite the whole damn thing...

-- Tore Haraldsen