home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
kermit.columbia.edu
/
kermit.columbia.edu.tar
/
kermit.columbia.edu
/
newsgroups
/
misc.19970929-19971216
/
000118_news@newsmaster….columbia.edu _Thu Oct 16 14:10:33 1997.msg
< prev
next >
Wrap
Internet Message Format
|
1997-12-15
|
3KB
Return-Path: <news@newsmaster.cc.columbia.edu>
Received: from newsmaster.cc.columbia.edu (newsmaster.cc.columbia.edu [128.59.35.30])
by watsun.cc.columbia.edu (8.8.5/8.8.5) with ESMTP id OAA18467
for <kermit.misc@watsun.cc.columbia.edu>; Thu, 16 Oct 1997 14:10:31 -0400 (EDT)
Received: (from news@localhost)
by newsmaster.cc.columbia.edu (8.8.5/8.8.5) id OAA28195
for kermit.misc@watsun; Thu, 16 Oct 1997 14:10:31 -0400 (EDT)
Path: news.columbia.edu!panix!howland.erols.net!newshub2.home.com!newshub1.home.com!news.home.com!news.rdc1.sfba.home.com!cypher.cagent.com!user
From: tsw@cagent.com (Tom Watson)
Newsgroups: alt.sys.pdp11,vmsnet.pdp-11,comp.protocols.kermit.misc
Subject: Re: DX11 baud rates under RT11
Date: Thu, 16 Oct 1997 11:08:16 -0700
Organization: CagEnt, Inc.
Lines: 43
Distribution: inet
Message-ID: <tsw-1610971108160001@cypher.cagent.com>
References: <RJM.97Oct15164024@swift.eng.ox.ac.uk> <6232gg$jnu$1@nntp.ucs.ubc.ca> <RJM.97Oct15235003@europa.ox.ac.uk>
NNTP-Posting-Host: aurora.cagent.com
Cache-Post-Path: aurora.cagent.com!unknown@cypher.cagent.com
Xref: news.columbia.edu alt.sys.pdp11:2886 vmsnet.pdp-11:8378 comp.protocols.kermit.misc:7897
In article <RJM.97Oct15235003@europa.ox.ac.uk>, rjm@europa.ox.ac.uk (Bob) wrote:
>
> Any idea how to interface an 8" drive to a PC? Would I need a Shugart
> type drive? I take it the RX01 type drives are no use in this regard?
> What software would I use under DOS to read RT11 volumes? (I think I
> have it, but I forget it's name).
>
Others have posted some commercial solutions to the "problem" but it
really isn't that bad. The basic 8" floppy uses the same data rates as a
1.2Meg 5 1/4" floppy. The big problem is the connector. The 8" drive
uses a 50 pin connector, and the 5 1/4" drive uses a 34 pin connector.
All of the signals are there, but as usual, IBM long ago diddled with
things a bit. They use a "twist" between the A & B drives to change the
selects, and because they needed to turn the motors on and off, they
flipped that signal as well. Most 8" drives have no motor control signal
(always on), so it really isn't a problem.
Why do I know about this?? I have a machine at home that uses (normally)
8" drives, and I've successfully hooked up 1.2Meg 5 1/4" floppies to it.
The biggest problem is the normal 8" drive has 77 tracks, but the 5 1/4"
one has 80 tracks. The other parameters (data rate [250/500k bits/sec],
rotational speed [360 RPM]) are the same.
Transferring of data via floppy disks? I'd use something that writes DOS
formatted files to the drive. The 'mtools' package (Linux) or 'dosread'
(Minix) can make these type of files (assuming you have the ability to
access the drive sector by sector). I suspect that reading the RT11
floppy on a PC would be the more difficult task. It would be doable, but
I don't know about the software that exists.
If anyone is interested, I'll go look at the little jumper block that I
built that converts the 50 pin 8" connector to the 34 pin 5 1/4"
connector. It is two IDC connectors with a bunch of wires. It costs less
than $10. to build (if you can get the parts).
That ends the hardware lesson for today, we now return you to the
regularly scheduled newsgroup.
--
tsw@cagent.com (Home: tsw@johana.com)
Please forward spam to: annagram@hr.house.gov (my Congressman), I do.