11 Aug
2013
11 Aug
'13
10:45 a.m.
It does not seem like I'll be able to find media for this gadget, so I've
move to Plan B: Reverse engineer the 5 existing diskettes I have.
Since the originals are read with a WD FDC chip, I thought this would be a
matter of letting ImageDisk have at it to determine the format.
Unfortunately, IMD cannot make heads or tails out of what's on the
diskettes. They do seem like they have 80-tracks, probably at 500KB/sec
data rate - at least that's what IMD tends to converge on in between
cascades of low-level data errors. Even at full analysis setting it's not
able to decide what it's looking at.
These diskettes read fine when I connect the unit to an Apple 2, so
whatever is on them is intact. Anyone have an idea how to decipher it?
I have a suspicion that they deliberately offset the tracks from a
"normal" position. At one point there was a special fluid available to
reveal magnetic domains under a magnifier, but this seems exotic and
not something I would know where to obtain.
Steve
--
11 Aug
11 Aug
12:01 p.m.
On 08/11/2013 07:45 AM, Steven Hirsch wrote:
It does not seem like I'll be able to find media
for this gadget, so
I've move to Plan B: Reverse engineer the 5 existing diskettes I have.
Since the originals are read with a WD FDC chip, I thought this would be
a matter of letting ImageDisk have at it to determine the format.
Unfortunately, IMD cannot make heads or tails out of what's on the
diskettes. They do seem like they have 80-tracks, probably at 500KB/sec
data rate - at least that's what IMD tends to converge on in between
cascades of low-level data errors. Even at full analysis setting it's
not able to decide what it's looking at.
These diskettes read fine when I connect the unit to an Apple 2, so
whatever is on them is intact. Anyone have an idea how to decipher it?
I have a suspicion that they deliberately offset the tracks from a
"normal" position. At one point there was a special fluid available to
reveal magnetic domains under a magnifier, but this seems exotic and not
something I would know where to obtain.
I've never had to read an Amlyn magazine, but if I read the patent
(4453188), the code (yes, they included 8080 assembly and PL/M source
code) states pretty clearly that servo tracks are used.
So there you go--the drive and its electronics appear to be sui generis.
CHM claims to have an OEM manual for the thing.
--Chuck
12:34 p.m.
On Sun, 11 Aug 2013, Chuck Guzis wrote:
On 08/11/2013 07:45 AM, Steven Hirsch wrote:
That makes sense. I assume that once it has located a track the data
stream is somewhat conventional in order for the WD chip to digest it.
It does not seem like I'll be able to find
media for this gadget, so
I've move to Plan B: Reverse engineer the 5 existing diskettes I have.
Since the originals are read with a WD FDC chip, I thought this would be
a matter of letting ImageDisk have at it to determine the format.
Unfortunately, IMD cannot make heads or tails out of what's on the
diskettes. They do seem like they have 80-tracks, probably at 500KB/sec
data rate - at least that's what IMD tends to converge on in between
cascades of low-level data errors. Even at full analysis setting it's
not able to decide what it's looking at.
These diskettes read fine when I connect the unit to an Apple 2, so
whatever is on them is intact. Anyone have an idea how to decipher it?
I have a suspicion that they deliberately offset the tracks from a
"normal" position. At one point there was a special fluid available to
reveal magnetic domains under a magnifier, but this seems exotic and not
something I would know where to obtain.
I've never had to read an Amlyn magazine, but if I read the patent (4453188),
the code (yes, they included 8080 assembly and PL/M source code) states
pretty clearly that servo tracks are used.
So there you go--the drive and its electronics appear to be sui generis. CHM claims to have an OEM manual for the thing.
Yes, unfortunately there is no information on how one gains access to
items in their archives. I've dropped them a note in the hopes that a
scan or copy is available.
Steve
--
1:23 p.m.
On 8/11/13 9:34 AM, Steven Hirsch wrote:
Yes, unfortunately there is no information on how one
gains access to items in their archives.
http://www.computerhistory.org/research/
2:25 p.m.
Once you find the track, then you can read easily. The track is pretty
normal. But the track positioning is 170TPI! (in its native mode).
It can also do 48,96,100 TPI, and could probably, with no real effort,
read disks with defective radial alignment!
You could: modify the stepper mechanism/radial alignment of a conventional
drive, to manually find the tracks. OR hook up a scope, and just start
shoving the head back and forth with a finger until you find a track.
On my 1990s TUIT list was: "add a micrometer spindle to the stepper of a
drive to be able to offset alignment".
Take a look at "Computer Technology Review" Winter 1983,
"Closed-Loop Positioning Method Raises Capacity Of 5.25" Floppy Disks" By
Richard E. Johnson of Amlyn
also:
[borrowed from an outgoing FPUIB cart]:
"AMLYN 1500 SERIES\nHIGH CAPACITY FLOPPY DISK DRIVVES\nPRODUCT
DESCRIPTION\n\n
The Amlyn 1500 Serieds Flexible Disk Drives are a family of new generation
flexible disk products from Amlyn Corporation. The Models 1550 and 1560
offer 1.66 and 3.32 megabytes respectively of unformatted capacity with
95milliseconds average access time and 500 kilobits per second data
transfer rate; the highest capacity and performance . . .
Amlyn Corporation has taken flexible disk technology into the next
generation . . . 9500 bits per inch and 170 tracks per inch to achieve the
highest . . .
To facilitat ease of system integration, The Amlyn 1500 Series utilizes
the industry standard SA460 electrical interface, track format and 8" data
transfer rate to minimize system modification . . .
. . . enabling easy database conversions and the use of existing . . . 48,
96, and 100 TPI 5 1/4" diskettes.
CLOSED LOOP SERVO
To reliably achieve a track density of 170 tracks per inch, the Amlyn 1500
Series employs a closed loop servo . . .
The basic elements of the system are a reference track on each diskette,
optical scale located on the head carriage, high speed precision 1.8
degree stepper motor and microcomputer control.
The reference track . . . serves as the point from which all data tracks
are located and is also used for analysis of, and subsequent compensation
for, anisotrophic growth of the diskette substrate . . .
Microcomputer control ... 59 microinches"
3:30 p.m.
On Sun, 11 Aug 2013, Fred Cisin wrote:
Once you find the track, then you can read easily. The
track is pretty
normal. But the track positioning is 170TPI! (in its native mode).
It can also do 48,96,100 TPI, and could probably, with no real effort,
read disks with defective radial alignment!
The question of the hour is how one might properly format new media for
the drive. I have exactly one pack with a few funky sectors on one of the
diskettes. I'm guessing the vendor must have had a custom jig to do the
servo writing.
--
3:55 p.m.
On Sun, 11 Aug 2013, Steven Hirsch wrote:
The question of the hour is how one might properly
format new media for
the drive. I have exactly one pack with a few funky sectors on one of the
diskettes. I'm guessing the vendor must have had a custom jig to do the
servo writing.
Once you have it in proper position, you can PROBABLY reformat a track.
The drive is presumably able to read, but not write the special servo.
3:58 p.m.
On 08/11/2013 12:30 PM, Steven Hirsch wrote:
The question of the hour is how one might properly
format new media for
the drive. I have exactly one pack with a few funky sectors on one of
the diskettes. I'm guessing the vendor must have had a custom jig to do
the servo writing.
Exactly so--just like Drivetec. It seems that Amlyn used separate servo
tracks, where Drivetec used an embedded servo (markers offset from track
center located in the inter-sector gap). The Amlyn approach seems to be
to read the dedicated servo track and microposition to get maximum
amplitude.
But I don't see why an old Drivetec mech couldn't be used to handle the
Amlyn floppies. Writing them might take some doing, however. Has
anyone ever succeeded in writing Drivetec-compatible tracks?
--Chuck
2:27 p.m.
On Sun, 11 Aug 2013, Al Kossow wrote:
On 8/11/13 9:34 AM, Steven Hirsch wrote:
Thanks! It wasn't obvious to me that 'Research' was the appropriate
category for media copying. Much as I'd love to contribute, my immediate
problem is not serious enough to warrant $75 + lord-knows-how-many pages
of photocopying at $0.50 per page.
I'm curious why you aren't scanning in documents? Or, does that $0.50 per
page cover the initial scan?
Steve
--
Yes, unfortunately there is no information on how
one gains access to items
in their archives.
http://www.computerhistory.org/research/
1:16 p.m.
On 08/11/2013 07:45 AM, Steven Hirsch wrote:
At one point there was a special fluid available to
reveal magnetic domains under a magnifier, but this seems exotic and not
something I would know where to obtain.
It's still available:
http://www.magneticdeveloper.com/
Nice people. The original Magnasee, etc. used Freon as their carrier.
I believe that Kyread uses an HCFC as the medium. In any case, if my
experience is an indicator, do not store the bottle with the provided
dropper as a cap. In a few months, you'll be looking at a bottle with
brown dust in the bottom and little else. Use the original cap for storage.
--Chuck
1:41 p.m.
On 08/11/2013 07:45 AM, Steven Hirsch wrote:
> At one point there was a special fluid available to
> reveal magnetic domains under a magnifier, but this seems exotic and not
> something I would know where to obtain.
"exotic"? how else would you splice helical scan video without major
glitches? :-)
On Sun, 11 Aug 2013, Chuck Guzis wrote:
It's still available:
http://www.magneticdeveloper.com/
Nice people. The original Magnasee, etc. used Freon as their carrier.
I believe that Kyread uses an HCFC as the medium. In any case, if my
experience is an indicator, do not store the bottle with the provided
dropper as a cap. In a few months, you'll be looking at a bottle with
brown dust in the bottom and little else. Use the original cap for storage.
One of my colleagues made his own! Just rust and a carrier (oil?)
He then used scotch tape to lift the developed image.
A few weeks from now, I'll pull that out of the FPUIB boxes.
--
Grumpy Ol' Fred cisin at xenosoft.com
2:24 p.m.
On Sun, 11 Aug 2013, Fred Cisin wrote:
Good point. I forgot there was a time when this was done. There was a
short blurb on the CBS news the other week that mentioned the paucity of
working Ampex videotape machines. Apparently there is one organization or
person still able to rebuild and maintain these.
On 08/11/2013
07:45 AM, Steven Hirsch wrote:
> At one point there was a special fluid available to
> reveal magnetic domains under a magnifier, but this seems exotic and not
> something I would know where to obtain.
"exotic"? how else would you splice helical scan video without major
glitches? :-) On Sun, 11 Aug 2013, Chuck Guzis wrote:
It would be a real treat if your remaining stock of Minipac cartridges (or
even bare diskettes) surfaces :-).
Steve
--
It's still available:
http://www.magneticdeveloper.com/
Nice people. The original Magnasee, etc. used Freon as their carrier.
I believe that Kyread uses an HCFC as the medium. In any case, if my
experience is an indicator, do not store the bottle with the provided
dropper as a cap. In a few months, you'll be looking at a bottle with
brown dust in the bottom and little else. Use the original cap for storage.
One of my colleagues made his own! Just rust and a carrier (oil?)
He then used scotch tape to lift the developed image.
A few weeks from now, I'll pull that out of the FPUIB boxes.
2:41 p.m.
> "exotic"? how else would you splice
helical scan video without major
> glitches? :-)
On Sun, 11 Aug 2013, Steven Hirsch wrote:
Good point. I forgot there was a time when this was
done. There was a
short blurb on the CBS news the other week that mentioned the paucity of
working Ampex videotape machines. Apparently there is one organization or
person still able to rebuild and maintain these.
"Nobody does that any more, nor ever will again!"
It would be a real treat if your remaining stock of
Minipac cartridges (or
even bare diskettes) surfaces :-).
Yes!
I feel bad that they haven't surfaced yet, and I'm already nearly an
eighth of the way through the crap^H^H^H^Hgoodies.
--
Grumpy Ol' Fred cisin at xenosoft.com
2:55 p.m.
Good point. I forgot there was a time when this was
done. There was a
short blurb on the CBS news the other week that mentioned the paucity of
working Ampex videotape machines. Apparently there is one organization or
person still able to rebuild and maintain these.
It is not like that at all. Last Sunday I was talking to a friend
about the old 2 inch video decks, and how many are in operational
condition, and he said "about 50". There are plenty of places that
maintain these machines for not-quite-everyday use.
--
Will
3:27 p.m.
On Sun, 11 Aug 2013, William Donzelli wrote:
Well, I don't expect 100% accuracy from the 1/2-hour nightly news :-)
Good to know that they haven't all been orphaned yet. Losing anything on
storage media due to a lack of something to read it drives me nuts.
--
Good point. I
forgot there was a time when this was done. There was a
short blurb on the CBS news the other week that mentioned the paucity of
working Ampex videotape machines. Apparently there is one organization or
person still able to rebuild and maintain these.
It is not like that at all. Last Sunday I was talking to a friend
about the old 2 inch video decks, and how many are in operational
condition, and he said "about 50". There are plenty of places that
maintain these machines for not-quite-everyday use.
4:45 p.m.
> Good point. I forgot there was a time when this
was done. There was a
> short blurb on the CBS news the other week that mentioned the paucity of
> working Ampex videotape machines. Apparently there is one organization or
> person still able to rebuild and maintain these.
On Sun, 11 Aug 2013, William
Donzelli wrote:
It is not like that at all. Last Sunday I was talking
to a friend
about the old 2 inch video decks, and how many are in operational
condition, and he said "about 50". There are plenty of places that
maintain these machines for not-quite-everyday use.
The jawflappers will often convey the "common knowledge" that nothing over
10 years old can be read. If THEIR office has abandoned all prior
compatibility, then surely EVERYONE has. And, if THEY don't know how to
read VHS, photo negatives, mag tape, reel to reel audio or video tape,
player piano rolls, CP/M disks, 8", or even 5.25", then surely it is a
skill involving "RARE, UNIQUE, UNOBTAINABLE, NO LONGER IN
EXISTENCE" "special hardware", and "is a majopr crisis in
industry".
If/when you ever try to followup on any of these stories of priceless
data being inaccessible, and/or even offer to HELP, you will find that it
was inaccessible UNTIL they contacted somebody, ANYBODY, who had a clue.
It is a recurring bit of Miss Information from the "news".
--
Grumpy Ol' Fred cisin at xenosoft.com
6:47 p.m.
I do recall a sale of the cartridges in the 80's sometime here in
Southern California, when everyone turned up with cartridges (and few
drives). The floppies could be pulled and used quite nicely with AT
drives, so a lot went that way.
I may have a banker box full of such media somewhere, if I run across
it, I'll post here in the future. Probably hidden like Fred's pile of
treasures.
I think the media was represented as similar to the Drivtec as far as
repurposing it for AT use.
I don't know that any of the media like that was that great as far as
how well it lasted, but I did use some Drivetec media in such a way.
I think when the Amlyn cartridges showed up, I kept the cartridges
because the AT media was then showing up cheaply at the local swap
meets, so the temptation or need to use it for AT media was not there.
2:31 p.m.
I think that it is 360RPM, and I DON"T think that it has a 300RPM rotation
speed, so therefore, reading 300 RPM diskettes would require that the FDC
support a 300K bps data transfer rate (present in early IBM AT FDCs), and
150K for SD?
--
Grumpy Ol' Fred cisin at xenosoft.com
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18 comments
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participants (6)
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aek＠bitsavers.org -
cclist＠sydex.com -
cisin＠xenosoft.com -
jws＠jwsss.com -
snhirsch＠gmail.com -
wdonzelli＠gmail.com