jsweet@ICS.UCI.EDU (Jerry Sweet) (09/10/86)
Since it's been at least 48 hours since I last got a response on this
subject, I now summarize the messages that I received.
Some judicious editing has been applied.
In general, the answer to my original query (given below) is: yes, the
Digital floppies (called RX-50s) are preformatted. No, you can't
format floppies on a uVAX-II/VMS system. However, you can format
floppies for use with the uVAX on the DEC Rainbow under CP/M using the
normal FORMAT program. There are apparently also alternative and
cheaper sources of RX-50s than DEC.
For whatever it's worth, there's probably a market out there for a
cheap floppy formatting program for uVAX-II systems, particularly if
it's more cost-effective than (a) buying RK-50s or (b) buying a
suitable PC to do the formatting.
Read and be informed. Thanks to all who responded.
Disclaimer: I have tried none of these suggestions. I have access
to a uVAX only infrequently.
------- Forwarded Messages
Date: Thu, 14 Aug 86 20:45:37 -0800
From: Jerry Sweet <jsweet@ICS.UCI.EDU>
This has probably been asked before, BUT at least not since mid-May,
which is how far back our info-vax archives go.
My limited experience with MicroVAX-II diskettes has been: "Digital"
brand floppies work in the drives, but others do not. Is there
anything really special about Digital's floppies, e.g. pre-formatting
or some other marketing conspiracy? Has anyone had a successful
experience with non-Digital floppies? I've never heard of a (commonly
available) >96tpi diskette, but is that what's required? What's the
story?
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Date: Fri 15 Aug 86 13:57:33-EDT
From: Greg Christy <GC0H@te.cc.cmu.edu>
We have been using Verbatim's RX50 format diskettes for quite a while,
and I have found them quite satisfactory. Do you clean your floppy
drives regularly? It really makes a difference if you clean them.
-------
Date: 15 Aug 1986 12:42-PDT
From: CHRIS@usc-eclb.arpa
If the uVax II has RX50s, then standard 5.25" ss 96 tpi floppies
should work, with one major caveat: you have to be able to format
them. DEC probably doesn't sell a formatter for uVax's, but a
Rainbow or Pro-350 will format the same disks. Note that there
is some difficulty with getting even those formatting programs.
-------
Date: Sat, 16 Aug 86 16:53 PST
From: 8250480%UWAV4.BITNET@wiscvm.wisc.edu
As I understand it, the diskettes you use are Digital's RX50's. This
is a special format diskette designed especially for Digital personal
computers and micro-systems. Factory preformatting is supposed to
save time and aid drive-to-drive interchangeability.
I own a DEC Rainbow (which also uses these diskettes). However, the
diskette (re)formatter program under CP/M in effect produces RX50's
from any blank diskette... I use Nashua brand, double-sided, double-
density, diskettes simply because I can get them for approximately
$7 per box of 10 (with sleeves, labels, write-protect tabs) as compared
to Digital's current price of $32 (I think it used to be $50) per box
of 10. These DEC machines only use one side, I only use the double-
sided diskettes because I get them cheaper than single-sided.
In summary, I think you can use any double-density diskette, you'll
just need to run it through the FORMAT program under CP/M on a
Rainbow... As I understand it, there is no way to format these on
the Micro-VAX. Digital wants you to either buy their Rainbow PC, or
spend mega-bucks on their floppies (rather devious). The 96tpi
floppies are supposed to be higher "quality" than double-density,
though in my opinion this is just a marketing ploy to get more
money out of you! If there is a problem with the "quality" the
formatter program should find it (in which case you can discard that
one problem diskette). I haven't had a "problem diskette" yet.
You should be aware of Digital's warning NOT to use diskettes with
reinforced hub-rings. Though I have "occasionally" fed my Rainbow a
diskette with hub-ring without any problems.
In summary, find someone with a Rainbow where you can "make" all the
"RX50's" you desire... If you cannot do this, other companies (BASF
comes to mind) also make RX50's which can be had for much cheaper!
-------
Date: Sun, 17 Aug 86 10:17:47 PDT
From: Carl J Lydick <carl@cithex.caltech.edu>
Yes, the things are preformatted in a wierd way. This is nothing new to
DEC's floppy drives, though. Even the old RX02's needed preformatted disks:
if you tried formatting an unformatted disk, you'd get an error message about
15 seconds into the procedure complaining that the volume wasn't software
enabled, or something like that.
-------
Date: Fri 15 Aug 86 23:18:49-EDT
From: Uli Jon Roth <Ad0r@te.cc.cmu.edu>
As far as I can tell, the drives in a uvax II are the standard rx50's --
high density, single sided. I've seen Verbatim floppys of the same sort
for sale; there are probably others too. I seem to remember that when the
Rainbow first came out there wasn't a format program, but that one appeared
later. Can't vouche for that, though, since I've never dealt with Rainbows
that much. I've heard of people formatting disks on a Rainbow and using
them on uvaxes, though. If you really want to, you could use the double
sided, high density floppies, ie., ones for an AT/RT drive just fine, since
they're certified for the same density, and on both sides too. I don't
know about the possibilities of flippys, though.
-------
Date: Sun 17 Aug 86 23:17:48-PDT
From: David Roode <ROODE%BIONET@sumex-aim.arpa>
DEC's minifloppies are preformatted. I have heard that programs
exist for Rainbows to do the formatting but I can't confirm it.
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Date: Mon, 18 Aug 86 07:30 EDT
From: "I am only an egg." <JOHNSON%northeastern.edu@csnet-relay.arpa>
Last I heard, uVAX RX-50K's were something like quad density. I just
read the box. It's from MEMOREX and say one side, double density. I'm
confused. The box also says 1d-80. I think that's the model number. You
might as MEMOREX.
-------
Date: Mon, 18 Aug 86 10:24:38 BST
From: Martyn Johnson <maj%computer-lab.cambridge.ac.uk@cs.ucl.ac.uk>
RX50 diskettes are preformatted by Digital, but are not in any other respects
special. The disk has to be good enough quality to support quad density (i.e.
double density MFM recording at 96 tpi). I am told that disks with hub rings
are NOT recommended for the RX50 drive.
I don't believe it is possible to format an RX50 on a MicroVAX-II, but we have
successfully formatted disks for the MicroVAX-II on other machines. There is
nothing very magic about the format; I think the sectors may be numbered a bit
unconventionally but that is all.
We have done our formatting on an Acorn BBC Microcomputer with double density
disc controller.
In the UK, the computer supplies company INMAC offers preformatted diskettes
suitable for the RX50, but I have never actually bought any.
-------
Date: Tue, 19 Aug 86 09:38:58 edt
From: "Edmund C. Lam" <eclam%wateng.waterloo.edu@csnet-relay.arpa>
This is yet another DEC [expletive-deleted]-up. The microVAX-II
controller cannot format floppies. So you are stuck with buying DEC
floppies. We have Rainbows, and use the CP/M-86 diskette format
program to format floppies for our RX50's. This is the only way to get
around this!
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Date: Sun, 17 Aug 86 18:11:27 -0500
From: Art McClinton <art@mitre.arpa>
I use single or double sided double density floppies in my rainbow. We
use a rainbow to format floppies for the micro vax. DEC claims that
hub rings cause problems but to date have had no problems with hub
rings. Latest batch of floppies were 29 cents per floppy (quantity
100) from some where in Ohio. No problems. To format them on the
microvax requires a program that DEC only provides with the onsite
maintenance programs (extra money)
-------
Date: Mon, 18 Aug 86 08:12:24 -0500
From: ted@mitre-bedford.arpa
In a lab I used to work in we had an 11/73 with the same type of
floppies. We used non-DEC floppies formatted on a Rainbow and had no
problems at all with the disks. If you can find a Rainbow and the
formatting program, give it a shot.
-------
Date: Wed, 20 Aug 86 16:30:41+0900
From: Yoichi Shinoda <mcvax!koudai!shinoda@seismo.css.gov>
Diskettes for uVAX-IIs are so called RX50 format, which is formatted in
512(bytes/sector) * 10(sector/track) * 80(track/side) *
1(side/diskette) providing 400Kbytes of storage. (It's strange that
they are used as single sided diskettes.) Since commonly used format
(which diskette manufacturer recommends) is 512(bytes/sector) *
9(sector/track), we have to re-format factory formatted diskettes to
use with RX50 drives.
It's a kludge, but you can do it by making GAP2 shorter than those
standard. I've done it with my PC9801 (APC in U.S. ?) from NEC.
Remember, what you all have to do is to fit 10 sectors of 512 bytes
in a single track.