Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!lll-crg!nike!ucbcad!ucbvax!hplabs!hpcea!hpfcdc!hpfclj!rer
From: rer@hpfclj.HP.COM (Rob Robason)
Newsgroups: net.periphs
Subject: Re: magtape device naming conventions
Message-ID: <2470002@hpfclj.HP.COM>
Date: Thu, 18-Sep-86 18:20:30 EDT
Article-I.D.: hpfclj.2470002
Posted: Thu Sep 18 18:20:30 1986
Date-Received: Mon, 22-Sep-86 07:48:56 EDT
References: <605@tc-norm.fluke.UUCP>
Organization: HP Ft. Collins, Co.
Lines: 42

> It seems clear
> that we need to retain the /dev/{mt mt0 mt4 mt8 mt12 rmt*} conventions
> for compatibility with existing software.  What we would like to do,
> however, is create a parallel naming convention which would even make
> sense to novice users.

> The use of "n" and "r" obviously overloads the letters.  One could
> easily guess that "nrmt1600" was the nonrewinding buffered 1600 bpi
> device, when in fact in the above scheme it also specifies raw I/O.

In our next releases we will be adopting the System V naming
conventions.  These specifically address some of your concerns.  In this
approach there are sub-directories of /dev (/dev/mt for block devices,
/dev/rmt for character) into which similarly named devices are
installed.  The naming convention itself is as mnemonic as that which
you suggested, and is summarized as follows:

	#	-	sequentially assigned device number
	l|m|h	-	low(800), medium(1600) or high(6250) bpi
	[n]	-	optional flag for "no rewind on close"

an example for a 1600 bpi character tape with no rewind is:

		/dev/rmt/0mn

and the corresponding block device is:

		/dev/mt/0mn

We are also supporting the use of these as defaults for tar and mt,
falling back to the old names of the new ones are not found.  Tar will
try to use /dev/rmt/0m then fall back to /dev/rmt8, likewise, mt tries
to use /dev/rmt/0mn, falling back to /dev/rmt12.

If you are inclined to gag at this verbosity, think back to the time
when YOU were a novice:  How mnemonic did you find /dev/rmt8?

Anyway, if you're inclined to avoid the NIH (not invented here)
syndrome, this provides at least one solution with a precedent.

Rob Robason, HP SSO (Systems Software Operation), Fort Collins
(hplabs|ihnp4|hpfcse|csu-cs|hpbbn)!hpfcla!rer