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Date:      Mon, 8 May 2000 08:52:22 -0700 (PDT)
From:      John Polstra <jdp@polstra.com>
To:        msmith@freebsd.org
Cc:        current@freebsd.org
Subject:   Re: Undocumented tape devices in pax(1) 
Message-ID:  <200005081552.IAA62838@vashon.polstra.com>
In-Reply-To: <200005072348.QAA12373@mass.cdrom.com>
References:  <200005072348.QAA12373@mass.cdrom.com>

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In article <200005072348.QAA12373@mass.cdrom.com>,
Mike Smith  <msmith@FreeBSD.ORG> wrote:
> 
> Interesting.  I've never encountered a tape device to which the buffer 
> cache was applicable, except for the mythical SunOS swap-to-tape story, 

Back in the days when Unix ran on PDP-11s you could actually put a
filesystem on a tape and mount it -- if you were insane enough to sit
there and wait for it.  The block devices were intended for that.

> and the 'r' has always been "rewind" for as long as I can remember.

I think you're mistaken.  Unix tape devices traditionally rewound by
default on their last close.  The non-rewind device has historically
had an "n" in front of it (when it existed at all).  E.g., /dev/rmt0
was a character device which rewound on last close, while /dev/nrmt0
was a character device which did not rewind on last close.  There was
also a /dev/mt0 which was a block device that rewound on last close,
and a /dev/nmt0 which ... well, you get the idea.

John
-- 
  John Polstra                                               jdp@polstra.com
  John D. Polstra & Co., Inc.                        Seattle, Washington USA
  "Disappointment is a good sign of basic intelligence."  -- Chögyam Trungpa



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