5 Feb
2008
5 Feb
'08
7:57 a.m.
Hi,
I'm in the process of restoring a 11/83 back to
health. Its
going OK so far, but I'm in need of some TK50/70 tapes
for
the tape drive and some RX50 5.25" disks.
The RX50 disks - I'm assuming are different to regular
5.25" floppy disks (DSDD) - I do have some of those,
but
I'm told the magnetic composition of the RX50 disks is
different?
Finally, someone has changed one of the RX50 disk
units
for what looks like a standard (PC style) 5.25" disk
drive. I'm just wondering if this was a standard thing
to do, or a bodge?
All the best
Ian.
____________________________________________________________________________________
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5 Feb
5 Feb
9:27 a.m.
New subject: Looking for TK50 tapes & RX50 disks..
Hi, I an curator of computer museum brazil, and I have a lot of floppies
disks 5 1/4, could send more details? like a photo etc.
By the way, a friend mine in Dallas, have a lot of old stuffs, could you
contact him too.
Richard Byron, Computer reset www.computerreset.com
Jose carlos valle
2008/2/5, silvercreekvalley <silvercreekvalley at yahoo.com>:
Hi,
I'm in the process of restoring a 11/83 back to
health. Its
going OK so far, but I'm in need of some TK50/70 tapes
for
the tape drive and some RX50 5.25" disks.
The RX50 disks - I'm assuming are different to regular
5.25" floppy disks (DSDD) - I do have some of those,
but
I'm told the magnetic composition of the RX50 disks is
different?
Finally, someone has changed one of the RX50 disk
units
for what looks like a standard (PC style) 5.25" disk
drive. I'm just wondering if this was a standard thing
to do, or a bodge?
All the best
Ian.
____________________________________________________________________________________
Looking for last minute shopping deals?
Find them fast with Yahoo! Search.
http://tools.search.yahoo.com/newsearch/category.php?category=shopping
--
Jose Carlos Valle
Museu do Computador & Futuro da Tecnologia
tel:+5511-4666-7545 - cel 8609-7410
Brazil
10:08 a.m.
At 4:57 AM -0800 2/5/08, silvercreekvalley wrote:
The RX50 disks - I'm assuming are different to
regular
5.25" floppy disks (DSDD) - I do have some of those,
but
I'm told the magnetic composition of the RX50 disks is
different?
There is an old DOS tool for turning PC floppies into RX50 floppies.
IIRC, you need a 1.2Mb Floppy drive in the PC. I can't remember if
you convert DSDD or DSHD floppies to RX50's.
Finally, someone has changed one of the RX50 disk
units
for what looks like a standard (PC style) 5.25" disk
drive. I'm just wondering if this was a standard thing
to do, or a bodge?
Good question, sounds like you either have an RX33 or someone has
hacked a Teac of the correct model to work as an RX33.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
10:34 a.m.
On 05/02/2008 15:08, Zane H. Healy wrote:
Indeed. And those are considerably more reliable than RX50s are.
--
Pete Peter Turnbull
Network Manager
University of York
At 4:57 AM -0800 2/5/08, silvercreekvalley wrote:
I was about to answer this, but Zane beat me to it. DSDD (or SSDD) is
what you need, as RX50s are single-sided 80-track double-density MFM.
What's odd about the format is that it uses 10 sectors of 512 bytes per
track, which is quite a tight fit. That gives you a 400KB formatted floppy.
The RX50 disks - I'm assuming are different
to regular
5.25" floppy disks (DSDD) - I do have some of those,
but
I'm told the magnetic composition of the RX50 disks is
different?
There is an old DOS tool for turning PC floppies into RX50 floppies.
IIRC, you need a 1.2Mb Floppy drive in the PC. I can't remember if you
convert DSDD or DSHD floppies to RX50's. Finally,
someone has changed one of the RX50 disk
units
for what looks like a standard (PC style) 5.25" disk
drive. I'm just wondering if this was a standard thing
to do, or a bodge?
Good question, sounds like you either have an RX33 or someone has hacked
a Teac of the correct model to work as an RX33.
10:51 a.m.
At 3:34 PM +0000 2/5/08, Pete Turnbull wrote:
On 05/02/2008 15:08, Zane H. Healy wrote:
True, but they lack a certain "style". Call me crazy, but I rate the
RX50 up there with something like my SGI O2 when it comes to "style".
Granted all that style comes at a price, and in the case of an RX50,
that is a less reliable piece of hardware, but since I don't normally
use the floppy drive on my PDP-11 anyway... :^)
Besides I don't have a real RX33 or the hardware to put it in place.
If I did, I'd probably have it installed in my "souped up" /73.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
Good question, sounds like you either have an RX33
or someone has
hacked a Teac of the correct model to work as an RX33.
Indeed. And those are considerably more reliable than RX50s are. 
1:25 p.m.
Zane H. Healy wrote:
At 3:34 PM
+0000 2/5/08, Pete Turnbull wrote:
> >On 05/02/2008 15:08, Zane H. Healy wrote:
>
>> Good question, sounds like you either have an RX33 or someone has
>> hacked a Teac of the correct model to work as an RX33.
> Indeed. And
those are considerably more reliable than RX50s are.
True, but they lack a certain "style". Call me crazy, but I rate the
RX50 up there with something like my SGI O2 when it comes to "style".
Granted all that style comes at a price, and in the case of an RX50,
that is a less reliable piece of hardware, but since I don't normally
use the floppy drive on my PDP-11 anyway... :^)
Besides I don't have a real RX33 or the hardware to put it in place.
If I did, I'd probably have it installed in my "souped up" /73.
Zane
I have a DUAL!!!!!!!! RX33 floppy drive that looks almost exactly like
the dual RX50
drive - probably because I used the discarded case from an RX50. Since
the 2 bare RX33
drives arrived without an enclosure, I figured the best solution was to
place them INSIDE
the old RX50 enclosure and add the bottom skid plate. The cable end is
an edge connector
for both drives and is daisy chained WITHOUT the standard PC twist when
2 drives are
used - which requires the second drive to have a different DS setting.
A "Y" power cable
must be connected to both drives before the case is bolted into place
using 4 short bolts
to each floppy drive through the thin RX50 shell. The original holds in
the RX50 enclosure
accept the 40-pin cable and the power cable.
Any other questions I would be glad to answer.
Sincerely yours,
Jerome Fine
--
If you attempted to send a reply and the original e-mail
address has been discontinued due a high volume of junk
e-mail, then the semi-permanent e-mail address can be
obtained by replacing the four characters preceding the
'at' with the four digits of the current year.
9:18 p.m.
On Tue, 5 Feb 2008, Jerome H. Fine wrote:
While I never had any problems with the RX50, I found
that the big
advantage was the extra capacity!
The big problems I heard about regarding the RX50 were:
- Drive speed tolerance was looser than that required to format media,
which is why the Rainbow was shipped without a formatter.
- Hub reinforcements could allegedly damage the plastic fingers that
held the diskette hub.
- It was possible to step the drive beyond track zero.
Don't really know if any of these are true.
--
roger ivie
rivie at ridgenet.net
6 Feb
6 Feb
6:45 p.m.
On Tue, 5 Feb 2008, Jerome H. Fine wrote:
My guesses on these, based on the RX50 scheamtics...
While I never had any problems with the RX50, I
found that the big
advantage was the extra capacity!
The big problems I heard about regarding the RX50 were:
- Drive speed tolerance was looser than that required to format media,
which is why the Rainbow was shipped without a formatter.
The spindle motor is similar to that in many other drives of the time, a
DC motor with a coupled tachogenrator. Unlike most other drives, the
control circuit doesn't use the LM2917 chip, but I see no reason why the
DEC design shouldn't work well.
_But_ IIRC the RX5 0fromat was 10 512 byte sectors per track. That's
tight, and it might well need an accurate spindle speed (in particular
one that's not running too fast) to format a disk.
- Hub reinforcements could allegedly damage the
plastic fingers that
held the diskette hub.
It's been a long time since I've been inside an RX50, but I see no real
difference between the hubs on an RX50 and those on other drives.
- It was possible to step the drive beyond track zero.
Yes, Unkike most other drives, the RX50 stepper control circuit is not
inhibited by the track 0 signal logically ANDEd with (direction = out).
It's quite possible to step the heads out beyond track 0. Whether this
causes any real prolems I don't know.
-tony
5 Feb
5 Feb
9:53 p.m.
On Tue, Feb 05, 2008 at 01:25:14PM -0500, Jerome H. Fine wrote:
I don't have my dual!!! RX33 in my hands right now
(it is buried), but
I thought that RX33 drives were Teac in the first place. Do I remember
that incorrectly?
A real RX33 was a real Teac FD55GFR floppy drive with the jumpers
set in a way that made the RQDX3 happy. I have pulled FD55GFRs from
PCs and rejumpered them and hung them off of DEC equipment with total
success. I have never tried using a different model of floppy drive,
however.
Back in the day, when people were scrapping PC-ATs and clones, I
made a point of nabbing any FD55GFRs I saw. I don't think I used
anything else in PCs I built. The drive was, at one time, easy to
find, not terribly expensive, and, in my experience, quite reliable.
I know the jumper settings are floating around on the 'net. I'm sure
that many list members here could cough up the right settings as well.
The trick is to find the right drive these days, when they haven't
been in daily use for a lot of years.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 6-Feb-2008 at 02:40 Z
South Pole Station
PSC 468 Box 400 Temp -45.2 F (-42.9 C) Windchill -71.4 F (-57.4 C)
APO AP 96598 Wind 8.3 kts Grid 56 Barometer 674.5 mb (10836 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
9:59 p.m.
On Tue, Feb 05, 2008 at 07:51:31AM -0800, Zane H. Healy wrote:
True, but they lack a certain "style". Call
me crazy, but I rate the
RX50 up there with something like my SGI O2 when it comes to "style".
Granted all that style comes at a price, and in the case of an RX50,
that is a less reliable piece of hardware, but since I don't normally
use the floppy drive on my PDP-11 anyway... :^)
I remember seeing my first RX50 around 1984 or so (probably in a
Rainbow), and its style really did stand out. It's a shame that
it was all flash and no substance. At the time, however, 400KB
on a SS floppy was a shock to me - I was storing ~170K on C-64
floppies back then.
Besides I don't have a real RX33 or the hardware
to put it in place.
If I did, I'd probably have it installed in my "souped up" /73.
As I just posted, it's a Teac FD55GFR with RQDX3-friendly settings for
motor start, etc. I don't have a filler plate on mine, but the drive
itself mounts to the same sleds as the RX50 or RD5x or TK50, etc. If
you mean your Qbus PDP-11 isn't in a BA23 or doesn't have an RQDX3,
then I misunderstood.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 6-Feb-2008 at 02:50 Z
South Pole Station
PSC 468 Box 400 Temp -45.2 F (-42.9 C) Windchill -69.3 F (-56.3 C)
APO AP 96598 Wind 7.0 kts Grid 59 Barometer 674.5 mb (10836 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
7:18 p.m.
New subject: RX33 was Re: Looking for TK50 tapes & RX50 disks...
Zane H. Healy wrote:
Good question, sounds like you either have an RX33 or someone has
hacked a Teac of the correct model to work as an RX33.
So what are the requirements
for an RX33? Last summer I tried all the
DSHD drives I had scavenged from PCs and was able to get one model to
work. It was a Mitsumi D509V3. I have two stacked in a BA23 chassis
configured as a /73.
These were my jumper settings (and guesses at function):
=============
Mitsumi Newtronics D509V3
DS1 o o=o DS0
DS3 o o o DS2
o=o o MS
CH o=o o RDY
HD o o=o LD
LS o o=o 2S
DSn - drive select
MS - motor w/ DS (?)
CH - disk change (?)
RDY - ready (?)
LS - low speed (?)
2S - two speed (?)
=============
I have no documentation for the drive, but this seems to imply that the
RQDX3 needs disk change and speed change to work. Does this make sense
to anyone?
-chuck
9:10 p.m.
New subject: RX33 was Re: Looking for TK50 tapes & RX50 disks...
On Tue, 5 Feb 2008, Charles H Dickman wrote:
I have no documentation for the drive, but this seems
to imply that the RQDX3
needs disk change and speed change to work. Does this make sense to anyone?
Yes, it does indeed need disk changed and speed changing.
--
roger ivie
rivie at ridgenet.net
11:36 p.m.
New subject: RX33 was Re: Looking for TK50 tapes & RX50 disks...
At 7:18 PM -0500 2/5/08, Charles H Dickman wrote:
Zane H. Healy wrote:
As I recall there are very specific requirements. Let's see if I
remember enough for Google to find the info... Wow, I only had two
letters in the name of the Teac drive swapped and Google figured it
out.
Nearly 10 years ago I was able to find some of the Teac drives, but
never got around to getting this working. Now it might actually be
easier to find a real RX33 drive! Though I'm sure it wouldn't be
cheap.
Zane
===========================================================================
=====
Note 93.3 Low-end disk devices - The Digital difference
3 of 136
EISNER::KENNEDY "Terry Kennedy" 72 lines
16-JAN-1988 02:05
-< RX33 >-
---------------------------------------------------------------------------
-----
The DEC RX33 is an IBM AT-type drive with some jumper changes.
DEC's drive is some variant of the TEAC FD55G. I have exper-
imented and discovered that the following drives/jumperings
work with the RQDX3:
TEAC FD-55GFV-17-U
Jumpers in:
HG
I (Roman numeral 1)
U1
U2
DC
FG
DS0 (for first RX33)
DS1 (for second RX33)
Jumpers out:
(all others)
Install the terminator, RA1, on the last (or only) drive
TEAC FD-55GFR-540-U
Jumpers in:
I (Roman numeral 1)
U0
U1
DC2
FG
D0 (for first RX33)
D1 (for second RX33)
Jumpers out:
(all others)
Install the terminator, RA1, on the last (or only) drive
Toshiba FDD 6882E1J01 (or ND-08DE-G)
Jumpers in:
LD
DC
DE
D1 (for first RX33)
D2 (for second RX33)
Jumpers out:
(all others)
Install the terminator jumper, TM, on the last (or only) drive
I have purchased many of the TEAC 540 drives from JDR Micro-
devices in California, (800) 538-5000. They have the follow-
ing items of interest:
[NOTE: This is *old* info (1988) and probably isn't valid any more]
FD-55G High density drive - $129.95
FD-5Y 'Y' cable to power 2 drives from the BAnn box - $2.95
FD55-MHW Mounting hardware for two FD-55G drives - $2.95
FD55-FP Beige faceplate for FD-55G drive (black is std.) - $2.95
FD55-SPEC Specification for FD-55G drive - $5.00
FD55-MAINT Maintenance manual for FD-55G drives - $25.00
Therfore, you can get two RX33's for $265.80 with the Y cable and
mounting hardware - a far cry from DEC's $795.00 each...
You need an RQDX3 to run these drives, of course. You will also
need to save the skid plate from your RX50 drive.
If you order these drives elsewhere, please remember that the
mounting hole threads are *metric*. Finding the right screws
will be a lot harder than finding the drives!
===========================================================================
=====
Note 93.77 Low-end disk devices - The Digital difference
77 of 136
EISNER::KENNEDY "Terry Kennedy" 15 lines
19-JUL-1991 01:40
-< Newer Teac model for RX33 substitute >-
---------------------------------------------------------------------------
-----
A number of people have asked me for other RX33 substitutes, since the
Teac models I gave earlier in this thread are no longer available. I did
some experimenting and I have a new one for you:
The Teac FD-55GFR-149-U can be used as an RX33 by installing jumpers
on FG, DC, I, and D0 (for 1st drive) or D1 (for 2nd drive). The "I" jum-
per is hard to find - here's a picture:
LG o o
IS o o o<---- This is the "I" jumper
o<-/
DC o o o o
o o o
I've tested this with RX50 and RX33 media under XXDP+ and RSTS/E.
Terry Kennedy Operations Manager, Academic Computing
te... at spcvxa.spc.edu St. Peter's College, Jersey City, NJ USA
+1 201 915 9381 (voice) +1 201 435-3662 (FAX)
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
Good question, sounds like you either have an RX33 or someone has
hacked a Teac of the correct model to work as an RX33.
So what are the requirements
for an RX33? Last summer I tried all
the DSHD drives I had scavenged from PCs and was able to get one
model to work. It was a Mitsumi D509V3. I have two stacked in a BA23
chassis configured as a /73. 
6 Feb
6 Feb
12:22 a.m.
New subject: Looking for TK50 tapes & RX50 disks..
I have a few thousand tapes, of which several hundred are DEC, and most of
the DEC drives. If you need anything, feel free to contact me off list. A
lot of it is in storage until I move back in.
Paul
On Tue, Feb 5, 2008 at 6:57 AM, silvercreekvalley <
silvercreekvalley at yahoo.com> wrote:
Hi,
I'm in the process of restoring a 11/83 back to
health. Its
going OK so far, but I'm in need of some TK50/70 tapes
for
the tape drive and some RX50 5.25" disks.
The RX50 disks - I'm assuming are different to regular
5.25" floppy disks (DSDD) - I do have some of those,
but
I'm told the magnetic composition of the RX50 disks is
different?
Finally, someone has changed one of the RX50 disk
units
for what looks like a standard (PC style) 5.25" disk
drive. I'm just wondering if this was a standard thing
to do, or a bodge?
All the best
Ian.
____________________________________________________________________________________
Looking for last minute shopping deals?
Find them fast with Yahoo! Search.
http://tools.search.yahoo.com/newsearch/category.php?category=shopping
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13 comments
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