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From: lphillips@lpami.wimsey.bc.ca (Larry Phillips)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Kronos tape drive(r)
Message-ID: <1377@lpami.wimsey.bc.ca>
Date: 8 Apr 90 22:59:20 GMT
Lines: 57
Return-Path: <lpami!lphillips>
To: van-bc!rnews

In <90.04.08.15.44.14.537@ckctpa.UUCP>, crash@ckctpa.UUCP (Frank J. Edwards) writes:
>
>Larry:  the CLtd docs imply that QuarterBack can be used with a regular
>SCSI tape drive; just configure the tape drive as a harddisk.  Since
>QB talks directly to the .device it will access the tape in a sequential
>manner (is there any other way?)...  Any opinions? comments?

An early C Ltd controller had documentation with it that told how you could use
a tape as a destination for a DiskCopy. The idea was to configure both the
source disk and the destination tape, via mountlist entries, as disks having
the same geometry. I never did try it, since I only had the C Ltd controller in
the machine for a very short time.

How you go about making tape work is going to depend entirely on the driver
implementation for the C Ltd. controller. If it supports SCSIDirect in the
manner of scsidisk.h, then that's probably the way to go. Otherwise, you will
have to hope that their library has the hooks for sending commands to generic
SCSI devices. I think it probably does, snce that same driver could be used for
a printer, if I remember correctly.

In more general terms, once you figure out how you can communicate with the
tape, you have a number of ways you can approach the problem. The quickest, and
probably the easiest way is to write individual programs that use the tape. The
advantage here is that you don't need to learn how to write and install
handlers, libraries, and so on. The disadvantage is that only your program(s)
will be able to access the tape.

A more general solution would be to write a handler that implements a file
system specifically tailored to tape. It would allow you to mount the tape as a
device, and to write to or read from tape, albeit with the limitations
inherent to a serial medium. The handler will have to recognize Amigados
packets and in turn communicate with the driver itself. The handler could
implement a file system for general copying, and could include extra goodies to
make the tape into a 'raw' device for such things as custom backup formats,
tar, etc.

I haven't looked into it deeply at all yet, so I don't know what probolems you
might run into. For example, there may be a need for packets that are not
standard Amigados packets, in which case, any operations requiring those
packets would be accessable only to custom-written programs that knew how to
build the right packets.

For further information of writing a handler, I recommend Transactor for the
Amiga, Vol 2, issues 2, 3, and 4, in which a couple of 'Software Distillery'
folks show how it's done.

Good luck.

-larry

--
Entomology bugs me.
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|   //   Larry Phillips                                                 |
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