*BSD News Article 12701


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Newsgroups: comp.os.386bsd.development
Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!howland.reston.ans.net!wupost!cs.utexas.edu!geraldo.cc.utexas.edu!portal.austin.ibm.com!awdprime.austin.ibm.com!fredriks
From: fredriks@austin.ibm.com (Lars Fredriksen)
Subject: Tape IOCTLS
Originator: @worf.cet.austin.ibm.com
Sender: news@austin.ibm.com (News id)
Message-ID: <C3p36H.2x89@austin.ibm.com>
Date: Wed, 10 Mar 1993 22:44:40 GMT
Organization: IBM Austin
Lines: 28


Hi,
	I have been working with Julian to add to the scsi tape device
driver support for the TANDBERG 3600 series devices. If you have original
devices from TANDBERG the fix is simple, the drives that comes out of 
IBM R/6000 boxes are a little different. They support both variable and
fixed blocksize. AIX has an IOCTL to set the blocksize for the tape
device. If the blocksize is 0, then it is a variable device otherwise
it is a fixed blocksize device with blocksize of whatever you set (depends
on each tape device type).

	I have been looking everywhere I know to see if anyone else
but AIX supports this  STIOCHGP ioctl, but I haven't found any. According
to Keith Bostic, neither BSD 4.4 nor POSIX adresses this issue. I have
also looked in the SysV docs, but have come up empty handed.

	If anyone knows of the "standard way" of doing this, please let
me know if not I'll base it on AIX. By the way, can I use the STIOCHGP
define or do I need to come up with a new one (ie. would I be violating
any copyright/patent stuff?)

	Thanks for the info.


Lars
 
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