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From: mouse@mcgill-vision.UUCP (der Mouse)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: Accessing a VAX tape drive from a Sun 3
Keywords: Sun, VAX, Connectivity
Message-ID: <1280@mcgill-vision.UUCP>
Date: 2 Sep 88 00:39:40 GMT
References: <711@auvax.UUCP>
Organization: McGill University, Montreal
Lines: 27

In article <711@auvax.UUCP>, willis@auvax.UUCP (Tony Willis) writes:
> I have a Sun 3/160 with Sun OS3.5 which is connected over Ethernet to
> a Vax 785 running Ultrix.  [VAX has a tape, Sun doesn't.  Wants Sun
> to be able to use the tape drive.]

You have several options, of varying degrees of difficulty and utility.
The simplest one is probably to use the provided remote tape facilities
of /etc/rmt; see the man page for rmt in section 8.  This requires
recompiling your program to use rexec or rcmd or whatever-it-is to
connect from the Sun program to the VAX rmt.  (I trust Ultrix provides
/etc/rmt.)

I also have a library and server you can have which again requires
recompiling the program, but it gives better transparency.  (There are
rmt_open(), rmt_close(), rmt_read(), rmt_write, and rmt_ioctl(), which
behave just like the corresponding routines without the rmt_ except
that they connect to the server and speak to it.  Without /etc/rmt's
silly limitations.)

If you have no source to your program, and it doesn't provide any way
of using an alternate device name, you're out of luck.  It would be
possible to hack the Sun kernel to create a pseudo-tape device driver
which would then connect to the VAX, but that's far from trivial.

					der Mouse

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