*BSD News Article 2427


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Path: sserve!manuel!munnari.oz.au!uunet!haven.umd.edu!mimsy!jds
From: jds@cs.umd.edu (James da Silva)
Newsgroups: comp.unix.bsd
Subject: Re: 386BSD & SCSI - Multiple file tapes
Message-ID: <59214@mimsy.umd.edu>
Date: 24 Jul 92 18:01:22 GMT
References: <1992Jul23.125510.4250@ulrik.uio.no> <1992Jul23.130323.4617@ulrik.uio.no>
Sender: news@mimsy.umd.edu
Organization: University of Maryland, Department of Computer Science
Lines: 44

toreh@bootes.sds.no (Tore Haraldsen) writes:
>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.

I didn't find this to be necessary.  I just commented out a test in
asopen() in as.c as follows:

*** /tmp/,RCSt1000161	Sat Jul 25 18:24:22 1992
--- as.c	Sat Jul 25 18:23:48 1992
***************
*** 429,438 ****
--- 429,440 ----
  		}
  	}
  	
+ /*
  	if (as->tape &&  dev_part(dev)) {
  		error = EIO;
  		goto done;
  	}
+ */
  
  	as->scsi_cdb_len = 10;
  	bzero(cdb, 10);


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

I did have to mknod a device with the partition field set to 1 as mentioned
in the instructions at the top of as.c.  For a tape at target 2:

	ln /dev/ras2a /dev/rst2		# rewind device
	mknod /dev/nrst2 c 13 17	# no-rewind device

Jaime
.............................................................................
: Stand on my shoulders, : jds@cs.umd.edu  :		      James da Silva
: not on my toes.	 : uunet!mimsy!jds : Systems Design & Analysis Group