Subject: Re: Q: how to backup to a winchester tape drive?
To: Grant Miller , Max Bell <mbell@europa.com>
From: Trouble Free RecepPFFFFFFFFFFFFFFFF <jgraham@defender.VAS.viewlogic.com>
List: port-i386
Date: 12/04/1995 11:49:11
In addition, I believe that tape drives are not named conventionally after
disks; they have their own peculiar naming convention.

[ The rest of you who already know this may skip to your next message.]

Typically, tapes are designated as [e][n][r]CtU, where

	C	is the controller type; 'w' for an IDE tape; 's' for a
		SCSI tape; 'x' for a tape on a Xylogics controller
		(if you happen to be stuck with a SPARCheater or Sun 3).
		I'm sure others will be dreamed up in the future.

	t	Constant.  Stands for 'tape'.

	U	Unit number.  0 is the first tape device found, 1 is
		the second, etc.  It's probably good to nail down the
		targets and units in your kernel config.
		Historically, the density was controlled by the unit
		number, adding 8 to the unit for each level of density
		up to a maximum addition of 24.

	[e]	This is a new precedent and I'm not sure what it means
		(yet).

	[n]	Optional preceding 'n', indicating 'no-rewind-on-close'
		which means that, when you close the device, the tape
		stays where it is.  'mt st' is usually run on the
		NROC device so as to avoid shifting the tape after
		an inquiry [%].  The NROC device is also used if you
		intend to store more than one file on a tape.

	[r]	Optional preceding 'r', indicating that the 'raw' device
		is to be used.  Most often, the raw device IS used since
		block st drivers have proven sufficiently problematical
		for Sun (among others) not to include them in their
		distributions.  Personally, I think it'd be a boon since
		this would allow one to make a boot tape.  Of course,
		for that you'd need a ramdisk root drive as well.

	When two or more of [enr] are present, they are given in ASCII-
	betical order.

[%] Of course, this one is a moot point considering that the 'mt st'
command doesn't work right (yet).

Unless I Missed Something [TM], tapes don't reference wt0[a-h] because,
wouldn't you agree, it's silly to restrict a tape to eight files, one
of which encompasses the entire tape...?



				--*greywolf;
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