8 Jan
2023
8 Jan
'23
5:29 p.m.
When reading old floppies, how often is it advisable to clean the drive? I managed the
first 3.5” floppies no problem, I’m using a USB Floppy Drive hooked up to my Mac Laptop, I
was able to image them using “Disk Utility”. The next two floppies have had errors.
Though I think I was able to successfully copy all the files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it age? I know I’ve
got at least a couple cleaning floppies around here, but they’re *OLD*.
Zane
8 Jan
8 Jan
5:36 p.m.
I think people use alcohol to clean the ceramic heads. Not complicated, but getting in
there ...
You could also think about vacuuming or blowing crap out of the mechanism before cleaning
the heads.
Disks give errors, duh. Whatever you use to image a disk, use it as a first attempt, as
that may be the ONLY chance to save the contents. People put a disk in the drive, do a
directory scan, screw around some more. And then the disk is no longer readable. It
happens. Just bang it with whatever program you got before worrying what's on it.
I've never imaged a disk in a usb drive I don't think, can't help you there. I
habe written dos images to external drives though.
9 Jan
9 Jan
11:56 a.m.
On Jan 8, 2023, at 5:36 PM, Chris via cctalk
<cctalk(a)classiccmp.org> wrote:
Disks give errors, duh. Whatever you use to image a disk, use it as a first attempt, as
that may be the ONLY chance to save the contents. People put a disk in the drive, do a
directory scan, screw around some more. And then the disk is no longer readable. It
happens. Just bang it with whatever program you got before worrying what's on it.
At this point in time, this is advisable for almost any magnetic media any of us would be
working with. Though I’ll admit I have looked at a couple of the disks before imaging
them, I’m trying to remember to image first, then read the image.
Zane
12:47 p.m.
On 1/9/23 11:56, Zane Healy via cctalk wrote:
At this point in time, this is advisable for almost
any magnetic media
any of us would be working with. Though I’ll admit I have looked at a
couple of the disks before imaging them, I’m trying to remember to
image first, then read the image.
Half-inch open-reel magtapes seem to be an exception if the binder is in
good condition. Multiple passes through a drive may improve the
recoverability because of the "tape scraper" in the drive.
--Chuck
8 Jan
8 Jan
5:48 p.m.
For 5.25" RX50 floppies, I imaged 400 of them before I needed to clean the
drive... and even then I'm not sure it needed it...
Warner
On Sun, Jan 8, 2023, 6:29 PM Zane Healy via cctalk <cctalk(a)classiccmp.org>
wrote:
When reading old floppies, how often is it advisable
to clean the drive?
I managed the first 3.5” floppies no problem, I’m using a USB Floppy Drive
hooked up to my Mac Laptop, I was able to image them using “Disk Utility”.
The next two floppies have had errors. Though I think I was able to
successfully copy all the files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it
age? I know I’ve got at least a couple cleaning floppies around here, but
they’re *OLD*.
Zane
6:44 p.m.
When reading old floppies, how often is it advisable
to clean the drive? I managed the first 3.5” floppies no problem, I’m using a USB Floppy
Drive hooked up to my Mac Laptop, I was able to image them using “Disk Utility”. The next
two floppies have had errors. Though I think I was able to successfully copy all the
files off the one.
Depends. For RX01 (PDT) and RX02 drives I'll typically clean before
reading a new disk that has valuable info before reading it, and again
before using my "good" disks. If the disk is read and there's nothing on
the head then it goes into the "good" pile.
For RX50's same basic thing. A bad RX50 floppy can contaminate the head
and make a mess of otherwise good disks, so I try to keep the new disks
and disks I use separate.
Also, what is floppy drive cleaning fluid made of, and
how well does it age? I know I’ve got at least a couple cleaning floppies around here,
but they’re *OLD*.
I think most are compatible with 95% isopropyl. Most drives seem to be
ok with this as well except for CDC 9762's where it seemed to dissolve
the glue that held the head to the arms. Ask me how I found that out.
CZ
10:28 p.m.
If alcohol isn't a good idea, white vinegar or dilute ammonia could also work.
Ammonia is the world's best peneyrant as far as I'm concerned. But to get into
deep crevaces and crannies it needs time. Sometimes 24 - 48 hours. It will remove
somenpaint lickity split.
11:48 p.m.
On 1/8/23 22:28, Chris via cctalk wrote:
If alcohol isn't a good idea, white vinegar or
dilute ammonia could also work. Ammonia is the world's best peneyrant as far as
I'm concerned. But to get into deep crevaces and crannies it needs time. Sometimes 24
- 48 hours. It will remove somenpaint lickity split.
The traditional stuff pre-Montreal Accords was usually Freon TF or
similar chloroflourocarbon with perhaps some isopropanol mixed in. At
least that's what my big bottle of Xerox floppy cleaning liquid claims.
I suspect that some type of ether may also be suitable. I've largely
taken to cleaning tape heads with heptane--doesn't seem to bother
plastics any.
--Chuck
9 Jan
9 Jan
6:12 a.m.
On Jan 9, 2023, at 2:48 AM, Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 1/8/23 22:28, Chris via cctalk wrote:
Yes, I had a can of that Freon cleaner, and it works great on tape heads -- so presumably
floppy heads too since they have the same requirements.
Back in college I once helped clean 1311 disk drive heads, after a hydraulic system leak.
That was done with isopropyl alcohol. High purity in that particular case since it was
available at the chemistry department store room, but I would expect ordinary store bought
90%+ would work fine. You'll want to use some sort of lint free applicators.
paul
If alcohol isn't a good idea, white vinegar
or dilute ammonia could also work. Ammonia is the world's best peneyrant as far as
I'm concerned. But to get into deep crevaces and crannies it needs time. Sometimes 24
- 48 hours. It will remove somenpaint lickity split.
The traditional stuff
pre-Montreal Accords was usually Freon TF or
similar chloroflourocarbon with perhaps some isopropanol mixed in. At
least that's what my big bottle of Xerox floppy cleaning liquid claims.
I suspect that some type of ether may also be suitable. I've largely
taken to cleaning tape heads with heptane--doesn't seem to bother
plastics any. 
8 Jan
8 Jan
7:41 p.m.
On 1/8/23 19:29, Zane Healy via cctalk wrote:
When reading old floppies, how often is it advisable
to clean the drive? I managed the first 3.5” floppies no problem, I’m using a USB Floppy
Drive hooked up to my Mac Laptop, I was able to image them using “Disk Utility”. The next
two floppies have had errors. Though I think I was able to successfully copy all the
files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it age? I know I’ve
got at least a couple cleaning floppies around here, but they’re *OLD*.
I avoid Disk Utility like the plague.
dd works great, although MacOS's device naming is stupid. "diskutil
list" will show you what the floppy device is, and "sudo diskutil
unmountdisk diskX" will free it for imaging.
If you can source a Blue Pill, though, you can handwire it to a
floppy drive and run the greaseweazle tools...
https://github.com/keirf/greaseweazle/wiki/Blue-Pill-Direct
Good luck!
Doc
9 Jan
9 Jan
8:02 a.m.
On 1/8/23 23:21, Grant Taylor via cctalk wrote:
On 1/8/23 8:41 PM, Doc Shipley via cctalk wrote:
Short version is that the GUI Disk Utility hides too much of what
it's doing AND, more to the point, makes assumptions by default. Yes,
it's possible to override the default but after [holy crap!] 2 decades
of using it I still have to fumble around.
I much prefer the command-line "diskutil". It's the same tool, I guess,
but the CLI demands explicit control. In almost every operation that
writes to disk, if you leave out a parameter the operation doesn't
happen. Bonus, you can get very detailed diagnostic info.
Plus, you know... I'm still a little averse to pointy clicky.
Doc
I avoid Disk Utility like the plague.
Doc, will you please elaborate on why you avoid the Disk Utility (.app)?
11:51 a.m.
On Jan 9, 2023, at 8:02 AM, Doc Shipley via cctalk <cctalk(a)classiccmp.org> wrote:
On 1/8/23 23:21, Grant Taylor via cctalk wrote:
I think I can answer this one myself, after looking at the few images I’ve created. Based
on the size, and not digging deeper, it looks like the “dmg” format only stores what it
has to, so it doesn’t appear to be a byte-for-byte copy.
Zane
On 1/8/23 8:41 PM, Doc Shipley via cctalk wrote:
Short version is that the GUI Disk Utility hides too much of what it's doing AND,
more to the point, makes assumptions by default. Yes, it's possible to override the
default but after [holy crap!] 2 decades of using it I still have to fumble around.
I much prefer the command-line "diskutil". It's the same tool, I guess,
but the CLI demands explicit control. In almost every operation that writes to disk, if
you leave out a parameter the operation doesn't happen. Bonus, you can get very
detailed diagnostic info.
Plus, you know... I'm still a little averse to pointy clicky.
Doc I avoid Disk Utility like the plague.
Doc,
will you please elaborate on why you avoid the Disk Utility (.app)? 
10 Jan
10 Jan
11:11 a.m.
On Mon, 9 Jan 2023 at 17:02, Doc Shipley via cctalk
<cctalk(a)classiccmp.org> wrote:
Short version is that the GUI Disk Utility hides too much of what
it's doing AND, more to the point, makes assumptions by default. Yes,
it's possible to override the default but after [holy crap!] 2 decades
of using it I still have to fumble around.
This is a good point.
Disk Utility was pretty good up until Yosemite (10.10 for
non-Illiminati). Then Apple castrated it and ripped out most of the
facilities to specify partition sizes exactly and so on.
Up to High Sierra (10.13) it used a fairly standard *nix partitioning
layout, only on the non-case-sensitive Apple HFS+ filesystem from
Classic MacOS 8.1 back in 1998. (Apple's equivalent to FAT32, so to
speak.)
Mojave (10.14) switched to the new APFS.
Since then, Apple has been devising an increasingly complex set of
disk containers with limited or no write permissions, in efforts to
make the system more resilient. It is also worth noting that the disk
layout of Arm Macs is _substantially_ more complicated than that of
Intel ones.
Here's a guide to the structure in macOS 12, Monterey:
https://eclecticlight.co/2021/12/16/boot-disk-layout-in-macos-monterey/
The forthcoming version 13 is anticipated to be a lot more complex than that.
For my venerable Intel Macs, I have been known to just boot Ubuntu off
a USB key and use Gparted to set up the partitions, then reboot off a
macOS USB key and install onto the result.
--
Liam Proven ~ Profile: https://about.me/liamproven
Email: lproven(a)cix.co.uk ~ gMail/gTalk/FB: lproven(a)gmail.com
Twitter/LinkedIn: lproven ~ Skype: liamproven
UK: (+44) 7939-087884 ~ Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053
9 Jan
9 Jan
11:41 a.m.
On Jan 8, 2023, at 7:41 PM, Doc Shipley via cctalk
<cctalk(a)classiccmp.org> wrote:
On 1/8/23 19:29, Zane Healy via cctalk wrote:
For the CD’s and CD-R’s I’ve been doing, I started using Roxio Toast, but after a few the
DVD burner on my 2010 Mac Pro decided to stop reading disks. As a result I’ve been using
a vintage 2011 MacBook Pro, and unmounting the disk, then using dd.
What is the difference between a “Blue Pill” and a “Greaseweazle”?
I plugged in the USB Floppy to my modern Mac Laptop, and was pleasantly surprised to find
things working as well as they are. After a bit more fighting, I think those two floppies
are unreadable. The one I couldn’t even copy data out of. The other I was able to get
the data off of. These are floppies that haven’t been stored well, so I’m not surprised.
Looking into this, Greaseweazle looks interesting. I’d seen some of the posts about it,
but not really paid attention. I have to admit, in part, due to owning a Catweazle Zorro
board for my Amiga 3000, that I was never that happy with. It looks like everything is
there to then covert the Greaseweazle images to use on an emulator (I’d want to mostly use
on DOS Box).
As it happens, one of the CD-R’s that I imaged, contained basically all my Mac floppies, I
have found a couple that didn’t get imaged. I’d imaged them on my PowerMac 8500/180, when
I was getting ready to replace it with a PowerMac G4/450, as that’s when Apple dropped
floppy support.
I need to assess just what I have for PC Floppies, that I want to try to recover. At
least they *should* be easier to locate than what I’ve been working on so far.
Zane
When reading old floppies, how often is it
advisable to clean the drive? I managed the first 3.5” floppies no problem, I’m using a
USB Floppy Drive hooked up to my Mac Laptop, I was able to image them using “Disk
Utility”. The next two floppies have had errors. Though I think I was able to
successfully copy all the files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it age? I know I’ve
got at least a couple cleaning floppies around here, but they’re *OLD*.
I avoid Disk Utility like the plague.
dd works great, although MacOS's device naming is stupid. "diskutil list"
will show you what the floppy device is, and "sudo diskutil unmountdisk diskX"
will free it for imaging.
If you can source a Blue Pill, though, you can handwire it to a floppy drive and run the
greaseweazle tools...
https://github.com/keirf/greaseweazle/wiki/Blue-Pill-Direct
Good luck!
Doc 
8 Jan
8 Jan
9:20 p.m.
When I'm archiving disks and begin to get unrecoverable errors, I do a head
cleaning and, if the errors go away, it was a dirty head; but if they
don't, something's wrong with the disk.
Sellam
On Sun, Jan 8, 2023 at 5:29 PM Zane Healy via cctalk <cctalk(a)classiccmp.org>
wrote:
When reading old floppies, how often is it advisable
to clean the drive?
I managed the first 3.5” floppies no problem, I’m using a USB Floppy Drive
hooked up to my Mac Laptop, I was able to image them using “Disk Utility”.
The next two floppies have had errors. Though I think I was able to
successfully copy all the files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it
age? I know I’ve got at least a couple cleaning floppies around here, but
they’re *OLD*.
Zane
9 Jan
9 Jan
10:23 a.m.
On Sun, Jan 8, 2023, 6:29 PM Zane Healy via cctalk <cctalk(a)classiccmp.org>
wrote:
When reading old floppies, how often is it advisable
to clean the drive?
I managed the first 3.5” floppies no problem, I’m using a USB Floppy Drive
hooked up to my Mac Laptop, I was able to image them using “Disk Utility”.
The next two floppies have had errors. Though I think I was able to
successfully copy all the files off the one.
Also, what is floppy drive cleaning fluid made of, and how well does it
age? I know I’ve got at least a couple cleaning floppies around here, but
they’re *OLD*.
Also, a normal USB Floppy drive can only handle 1.44MB formatted floppies.
720k might work (but there is nothing in the standards to describe this)
and oddball formats are right out.
Warner
11:12 a.m.
On 1/9/23 10:23, Warner Losh via cctalk wrote:
Also, a normal USB Floppy drive can only handle 1.44MB formatted floppies.
720k might work (but there is nothing in the standards to describe this)
and oddball formats are right out.
I've found that most 3.5" USB floppy drives also support the 1.23MB
8x1024 disks. (e.g. legacy 3-mode drive equivalent).
Probably not useful for most people, but noteworthy.
--Chuck
9:16 p.m.
Hello Chuck
Speaking of old floppies, when I was busy converting floppies (I've now
been retired for 10 years) I frequently had problems reading some 5.25"
disks, but only on specific drives. Those disks came from IBM systems,
probably S/3.
I cannot be sure that the solution holds, but it was my experience that
those "faulty" discs could be read on TEAC FD235GFR drives orignating
from Japan. Not the ones from the Philippines ! That puzzled me, until I
called MIchael Cotgrove from (then) Intermedia in the UK, who told me
that he knew that some IBM systems ran the drives at a lower speed, and
that that very well could be the problem. After that explanation, I only
used the 142U version of the drive, and the problems went away.
Does this sound familiar?
--Nico
On 2023-01-09 20:12, Chuck Guzis via cctalk wrote:
On 1/9/23 10:23, Warner Losh via cctalk wrote:
Also, a normal USB Floppy drive can only handle
1.44MB formatted floppies.
720k might work (but there is nothing in the standards to describe this)
and oddball formats are right out.
I've found that most 3.5" USB floppy drives also support the 1.23MB
8x1024 disks. (e.g. legacy 3-mode drive equivalent).
Probably not useful for most people, but noteworthy.
--Chuck
10:14 p.m.
On 1/9/23 21:16, nico de jong via cctalk wrote:
Hello Chuck
Speaking of old floppies, when I was busy converting floppies (I've
now been retired for 10 years) I frequently had problems reading some
5.25" disks, but only on specific drives. Those disks came from IBM
systems, probably S/3.
I cannot be sure that the solution holds, but it was my experience
that those "faulty" discs could be read on TEAC FD235GFR drives
orignating from Japan. Not the ones from the Philippines ! That
puzzled me, until I called MIchael Cotgrove from (then) Intermedia in
the UK, who told me that he knew that some IBM systems ran the drives
at a lower speed, and that that very well could be the problem. After
that explanation, I only used the 142U version of the drive, and the
problems went away.
Does this sound familiar?
HI Nico,
It sounds puzzling to me--the FD235 is a 3.5" drive, so I'm not sure
what you were using to read the problem disks with.
--Chuck
10:28 p.m.
On 2023-01-10 07:14, Chuck Guzis via cctalk wrote:
On 1/9/23 21:16, nico de jong via cctalk wrote:
My apologies ! Read the wrong note... I was speaking about the FD5GFR !
-- Nico
Hello Chuck
Speaking of old floppies, when I was busy converting floppies (I've
now been retired for 10 years) I frequently had problems reading some
5.25" disks, but only on specific drives. Those disks came from IBM
systems, probably S/3.
I cannot be sure that the solution holds, but it was my experience
that those "faulty" discs could be read on TEAC FD235GFR drives
orignating from Japan. Not the ones from the Philippines ! That
puzzled me, until I called MIchael Cotgrove from (then) Intermedia in
the UK, who told me that he knew that some IBM systems ran the drives
at a lower speed, and that that very well could be the problem. After
that explanation, I only used the 142U version of the drive, and the
problems went away.
Does this sound familiar?
HI Nico,
It sounds puzzling to me--the FD235 is a 3.5" drive, so I'm not sure
what you were using to read the problem disks with.
--Chuck
10:31 p.m.
On 1/9/23 21:16, nico de jong via cctalk wrote:
> Hello Chuck
>
> Speaking of old floppies, when I was busy converting floppies (I've
> now been retired for 10 years) I frequently had problems reading some
> 5.25" disks, but only on specific drives. Those disks came from IBM
> systems, probably S/3.
>
> I cannot be sure that the solution holds, but it was my experience
> that those "faulty" discs could be read on TEAC FD235GFR drives
> orignating from Japan. Not the ones from the Philippines ! That
> puzzled me, until I called MIchael Cotgrove from (then) Intermedia in
> the UK, who told me that he knew that some IBM systems ran the drives
> at a lower speed, and that that very well could be the problem. After
> that explanation, I only used the 142U version of the drive, and the
> problems went away.
>
> Does this sound familiar?
On Mon, 9 Jan 2023, Chuck Guzis via cctalk wrote:
HI Nico,
It sounds puzzling to me--the FD235 is a 3.5" drive, so I'm not sure
what you were using to read the problem disks with.
A little quick speculation, but not determinable without the system, . . .
The Teac FD55F was a 96tpi "720K" drive at 300 RPM
The Teac FD55G was a "1.2M" drive. 360RPM
The FD55GF was both, and there were several variants, with different
jumpers, etc. (hence differences between the various ones)
Was the drive running at 300RPM, or 360RPM?
If the disks were HD, then they should have been at 360 RPM, with a data
transfer rate of 500K.
If the disks were NOT HD, and were 640K - 800K "quad" density, then they
should have been at 300RPM with 250K data transfer rate, OR at 360RPM with
a 300K data transfer rate.
Could you have been suffering from something as simple as a rotation
speed / data transfer rate mismatch?
The 5170 supported 250K data transfer rates ("360K" disk/drive)
500K data transfer rate ("1.2M" disk/drive)
and 300K data transfer rate ("360K" disk in "1.2M" drive)
--
Grumpy Ol' Fred cisin(a)xenosoft.com
10:50 p.m.
On 2023-01-10 07:31, Fred Cisin via cctalk wrote:
I think that this is a logical explanation. Nice to know guys like you
are still around :-)
Thanks
Nico
On 1/9/23 21:16, nico de jong via cctalk wrote:
> Hello Chuck
>
> Speaking of old floppies, when I was busy converting floppies (I've
> now been retired for 10 years) I frequently had problems reading some
> 5.25" disks, but only on specific drives. Those disks came from IBM
> systems, probably S/3.
>
> I cannot be sure that the solution holds, but it was my experience
> that those "faulty" discs could be read on TEAC FD235GFR drives
> orignating from Japan. Not the ones from the Philippines ! That
> puzzled me, until I called MIchael Cotgrove from (then) Intermedia in
> the UK, who told me that he knew that some IBM systems ran the drives
> at a lower speed, and that that very well could be the problem. After
> that explanation, I only used the 142U version of the drive, and the
> problems went away.
>
> Does this sound familiar?
On Mon, 9 Jan 2023, Chuck Guzis via cctalk wrote:
HI Nico,
It sounds puzzling to me--the FD235 is a 3.5" drive, so I'm not sure
what you were using to read the problem disks with.
A little quick speculation, but not determinable without the system, .
. .
The Teac FD55F was a 96tpi "720K" drive at 300 RPM
The Teac FD55G was a "1.2M" drive. 360RPM
The FD55GF was both, and there were several variants, with different
jumpers, etc. (hence differences between the various ones)
Was the drive running at 300RPM, or 360RPM?
If the disks were HD, then they should have been at 360 RPM, with a
data transfer rate of 500K.
If the disks were NOT HD, and were 640K - 800K "quad" density, then
they should have been at 300RPM with 250K data transfer rate, OR at
360RPM with a 300K data transfer rate.
Could you have been suffering from something as simple as a rotation
speed / data transfer rate mismatch?
The 5170 supported 250K data transfer rates ("360K" disk/drive)
500K data transfer rate ("1.2M" disk/drive)
and 300K data transfer rate ("360K" disk in "1.2M" drive)
--
Grumpy Ol' Fred cisin(a)xenosoft.com
11:12 p.m.
On 1/9/23 22:31, Fred Cisin wrote:
A little quick speculation, but not determinable without the system, .
. .
The Teac FD55F was a 96tpi "720K" drive at 300 RPM
The Teac FD55G was a "1.2M" drive. 360RPM
The FD55GF was both, and there were several variants, with different
jumpers, etc. (hence differences between the various ones)
Was the drive running at 300RPM, or 360RPM?
If the disks were HD, then they should have been at 360 RPM, with a
data transfer rate of 500K.
If the disks were NOT HD, and were 640K - 800K "quad" density, then
they should have been at 300RPM with 250K data transfer rate, OR at
360RPM with a 300K data transfer rate.
Could you have been suffering from something as simple as a rotation
speed / data transfer rate mismatch?
The 5170 supported 250K data transfer rates ("360K" disk/drive)
500K data transfer rate ("1.2M" disk/drive)
and 300K data transfer rate ("360K" disk in "1.2M" drive)
What Fred said. I'll add that a similar situation applies in the 3.5"
world. The standard in the Japanese NEC PC world was for all floppies
to share a common format, namely 8 sectors of 1024 bytes, starting with
the 8" drives, which normally spin at 360 RPM and use a 500Kb/sec data
transfer rate. So the IBM 5170 1.2MB drive in high-density is a direct
descendant of that, though early Japanese 1.2MB drives did not have a
low-density mode--and IBM elected to stick with 512 byte sectors.
Finally, we get to 3.5", where the NEC standard was 360 RPM, not 300.
This resulted in the "3-mode drive" where a pin (usually pin 4) is used
to switch the drive RPM between 300 and 360. The Teac FD235HG drives
can do this (assuming that they're jumpered correspondingly). The 1.23
MB format was used on a lot of Japanese CNC gear; e.g. Mitsubishi/Mazak.
--Chuck
10 Jan
10 Jan
12:25 a.m.
On 2023-01-10 08:12, Chuck Guzis via cctalk wrote:
On 1/9/23 22:31, Fred Cisin wrote:
That reminds me of the first microcomputer I had, back in 1985 or so. It
was a SORD (model 323?), which was "born" with 1 360k drive. I requested
the addition of a 5.25 1.2 MB drive, on the condition that it could read
and write IBM HD floppies. The operating system was a japanese MS-DOS
version. I had serious problems (like "unwritable") with the
drive/format, so I eventually, after 3 years, got a credit note :-)
-- NIco
A little quick speculation, but not determinable
without the system, .
. .
The Teac FD55F was a 96tpi "720K" drive at 300 RPM
The Teac FD55G was a "1.2M" drive. 360RPM
The FD55GF was both, and there were several variants, with different
jumpers, etc. (hence differences between the various ones)
Was the drive running at 300RPM, or 360RPM?
If the disks were HD, then they should have been at 360 RPM, with a
data transfer rate of 500K.
If the disks were NOT HD, and were 640K - 800K "quad" density, then
they should have been at 300RPM with 250K data transfer rate, OR at
360RPM with a 300K data transfer rate.
Could you have been suffering from something as simple as a rotation
speed / data transfer rate mismatch?
The 5170 supported 250K data transfer rates ("360K" disk/drive)
500K data transfer rate ("1.2M" disk/drive)
and 300K data transfer rate ("360K" disk in "1.2M" drive)
What Fred said. I'll add that a similar situation applies in the 3.5"
world. The standard in the Japanese NEC PC world was for all floppies
to share a common format, namely 8 sectors of 1024 bytes, starting with
the 8" drives, which normally spin at 360 RPM and use a 500Kb/sec data
transfer rate. So the IBM 5170 1.2MB drive in high-density is a direct
descendant of that, though early Japanese 1.2MB drives did not have a
low-density mode--and IBM elected to stick with 512 byte sectors.
Finally, we get to 3.5", where the NEC standard was 360 RPM, not 300.
This resulted in the "3-mode drive" where a pin (usually pin 4) is used
to switch the drive RPM between 300 and 360. The Teac FD235HG drives
can do this (assuming that they're jumpered correspondingly). The 1.23
MB format was used on a lot of Japanese CNC gear; e.g. Mitsubishi/Mazak.
--Chuck
11:05 a.m.
On Tue, 2023-01-10 at 06:16 +0100, nico de jong via cctalk wrote:
Speaking of old floppies
In about 1975, I was sharing an office with a lady who bought an Ohio
Scientific 6502 computer, with two 5.25 inch floppy disk drives,
instead of an Imsai 8800 with one 8.4 inch drive.
She got a tee shirt that said "I've got two floppies."
Except she didn't.
12:53 p.m.
On Tue, 10 Jan 2023, Van Snyder via cctalk wrote:
In about 1975, I was sharing an office with a lady who
bought an Ohio
Scientific 6502 computer, with two 5.25 inch floppy disk drives,
instead of an Imsai 8800 with one 8.4 inch drive.
She got a tee shirt that said "I've got two floppies."
Except she didn't.
The 5.25" drives were called "mini-floppies"
Just a couple years later, . . .
The Shugart SA400 was released in 1976, but was hard to get for a few
years.
The OSI Challenger was, IIRC, 1978
A few years later, I got a used ["Euro"]-Apple II, converted for USA use,
in an OSI Challenger case (with wood (walnu?) sides), with an external RCA
keyboard.
I would rather have had the OSI, but that wasn't available at the
computer swap.
OSI used a PIA chip, instead of a conventional FDC chip, so WD/NEC
style controllers can not read those disks.
1:23 p.m.
New subject: OSI floppies (Was: Reading Old Floppies
Ohio Scientific 6502 computer, with two 5.25 inch
floppy disk drives,
Shugart SA400 drive: 35 track, 48tpi
PIA/UART, instead of FDC chip.
"VERY soft-sector"
It is FM, at usual 125Kbps used on 5.25" single density, but, without
WD/IBM track and sector header format.
So, a flux transition board might work, or maybe even a "track read" of a
WD FDC. NEC "track read" is actually "multiple sector read", so will
not
work on other than WD/IBM track/sector format, without extra efforts to
FOOL the FDC into doing an actual track read (cf. reading Amiga on PC)
https://torlus.com/floppy/forum/viewtopic.php?t=1284
has some details on the floppy format!
"Each track has a track header, which is written and read approximately 1
ms after the index pulse, consisting of a 2-byte track start code,
followed by the track number in BCD, followed by a stop byte code. The
track header is followed by a software-defined gap.
"Each sector is indicated by a sector start code, followed by a sector
number byte, followed by the sector length, followed by the sector data
(the length in pages multiplied by 256 bytes), followed by a sector end
sequence. There is a software-defined gap between each sector."
https://osiweb.org/computes_gazette/Compute_n020_p136_OS65D_Disk_Routines_P…
https://osiweb.org/computes_gazette/Compute_n021_p118_OS65D_Disk_Routines_P…
1:32 p.m.
On Tue, Jan 10, 2023 at 12:53 PM Fred Cisin via cctalk <
cctalk(a)classiccmp.org> wrote:
A few years later, I got a used
["Euro"]-Apple II, converted for USA use,
in an OSI Challenger case (with wood (walnu?) sides), with an external RCA
keyboard.
Did the motherboard have an additional RAM chip to accommodate the
PAL-based hi-res graphics resolution?
Sellam
1:41 p.m.
> A few years later, I got a used
["Euro"]-Apple II, converted for USA use,
> in an OSI Challenger case (with wood (walnu?) sides), with an external RCA
> keyboard.
On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
Did the motherboard have an additional RAM chip to
accommodate the
PAL-based hi-res graphics resolution?
I don't remember. It was working as an AppleII
If you didn't get it, then maybe Eric Smith?
2:04 p.m.
Was it this style (Challenger 4P)?
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
I can't remember if I ever had a 4P but I did have I think two 2 or 2P
models.
Either way, I'm not sure if I got any from you, but in the end, if I did,
you know what happened.
I do still have a Challenger motherboard around here somewhere, as well as
I think an OSI of some model in a custom-built big-box style enclosure.
Sellam
On Tue, Jan 10, 2023 at 1:41 PM Fred Cisin via cctalk <cctalk(a)classiccmp.org>
wrote:
> A few
years later, I got a used ["Euro"]-Apple II, converted for USA
use,
> in an OSI Challenger case (with wood (walnu?)
sides), with an external
RCA
> keyboard.
On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
Did the motherboard have an additional RAM chip
to accommodate the
PAL-based hi-res graphics resolution?
I don't remember. It was working as an AppleII
If you didn't get it, then maybe Eric Smith?
2:20 p.m.
> A few years later, I got a used
["Euro"]-Apple II, converted for USA
> use, in an OSI Challenger case (with wood (walnu?) sides), with an
> external RCA keyboard.
> If you didn't get it, then maybe Eric Smith?
On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
Was it this style (Challenger 4P)?
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
I can't remember if I ever had a 4P but I did have I think two 2 or 2P
models.
Either way, I'm not sure if I got any from you, but in the end, if I did,
you know what happened.
I do still have a Challenger motherboard around here somewhere, as well as
I think an OSI of some model in a custom-built big-box style enclosure.
Yes, it was that style, but BLUE
No floppy unit.
The external RCA keyboard was black, and a splash resistant case.
3:18 p.m.
Yes, the 2/2P models I [think I] had were blue.
Sellam
On Tue, Jan 10, 2023 at 2:21 PM Fred Cisin via cctalk <cctalk(a)classiccmp.org>
wrote:
> A few
years later, I got a used ["Euro"]-Apple II, converted for USA
> use, in an OSI Challenger case (with wood (walnu?) sides), with an
> external RCA keyboard.
> If you didn't get it, then maybe Eric Smith?
On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
Was it this style (Challenger 4P)?
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
I can't remember if I ever had a 4P but I did
have I think two 2 or 2P
models.
Either way, I'm not sure if I got any from you, but in the end, if I did,
you know what happened.
I do still have a Challenger motherboard around here somewhere, as well
as
I think an OSI of some model in a custom-built
big-box style enclosure.
Yes, it was that style, but BLUE
No floppy unit.
The external RCA keyboard was black, and a splash resistant case.
3:23 p.m.
Speaking of reading old floppies, I got my Model 100 and Tandy Portable
Disk Drive down from the shelf to read some old floppies I found from
the 1980's. 3.5 inch disks with a whopping 100k capacity each!
Problem was drive was saying the disks were "not formatted". Took it
apart, found that the belt had literally turned to black goo and wrapped
itself around the capstain. Cleaned it off (took forever), then put on a
new modern belt that I use for TU58 Dectape II tapes. Fit, bit tight but
fit.
Drive works great! And some of the stuff I wrote in the 1980's.... Old
posts to compuserve's pdp11 forum, ancient bitnet messages, stuff about
getting the pdp8/L and passing up other stuff... Could have bought a
Vax730 with R80/RL02 for 3k but didn't have the money.
All in all a fun trip down memory lane. And I kept thinking "Was I
really that naive?
C
On 1/10/2023 6:18 PM, Sellam Abraham via cctalk wrote:
Yes, the 2/2P models I [think I] had were blue.
Sellam
On Tue, Jan 10, 2023 at 2:21 PM Fred Cisin via cctalk <cctalk(a)classiccmp.org>
wrote:
>>> A few years later, I got a used ["Euro"]-Apple II, converted for
USA
>>> use, in an OSI Challenger case (with wood (walnu?) sides), with an
>>> external RCA keyboard.
>>> If you didn't get it, then maybe Eric Smith?
>
> On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
>> Was it this style (Challenger 4P)?
>>
>
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
>> I can't remember if I ever had a 4P but I did have I think two 2 or 2P
>> models.
>> Either way, I'm not sure if I got any from you, but in the end, if I did,
>> you know what happened.
>> I do still have a Challenger motherboard around here somewhere, as well
> as
>> I think an OSI of some model in a custom-built big-box style enclosure.
>
> Yes, it was that style, but BLUE
> No floppy unit.
> The external RCA keyboard was black, and a splash resistant case.
>
10:19 p.m.
The "Tandy Portable Disk Drive" was a strange beast. At one time, some
folk wrote software to run on PC to operate it.
Otherwise, it's another flux transition project.
OTOH, RS also had an external 5.25" box ("Disk/Video Interface"), which
has a very simple MFM format, with the Microsoft Stand-Alone BASIC file
system (much like certain models of NEC machines) with some slight
resemblance to the file system on the Coco.
On Tue, 10 Jan 2023, Chris Zach via cctalk wrote:
Speaking of reading old floppies, I got my Model 100
and Tandy Portable
Disk Drive down from the shelf to read some old floppies I found from
the 1980's. 3.5 inch disks with a whopping 100k capacity each!
Problem was drive was saying the disks were "not formatted". Took it
apart, found that the belt had literally turned to black goo and wrapped
itself around the capstain. Cleaned it off (took forever), then put on a
new modern belt that I use for TU58 Dectape II tapes. Fit, bit tight but
fit.
Drive works great! And some of the stuff I wrote in the 1980's.... Old
posts to compuserve's pdp11 forum, ancient bitnet messages, stuff about
getting the pdp8/L and passing up other stuff... Could have bought a
Vax730 with R80/RL02 for 3k but didn't have the money.
All in all a fun trip down memory lane. And I kept thinking "Was I
really that naive?
C
10:22 p.m.
I had the same issue with one of those drives. I think I may have it but I
need to source a belt to fix it. The black goop that used to be the belt
got all over the mechanism. It was a pain to clean off completely.
Sellam
On Tue, Jan 10, 2023 at 10:11 PM Chris Zach via cctalk <
cctalk(a)classiccmp.org> wrote:
Speaking of reading old floppies, I got my Model 100
and Tandy Portable
Disk Drive down from the shelf to read some old floppies I found from
the 1980's. 3.5 inch disks with a whopping 100k capacity each!
Problem was drive was saying the disks were "not formatted". Took it
apart, found that the belt had literally turned to black goo and wrapped
itself around the capstain. Cleaned it off (took forever), then put on a
new modern belt that I use for TU58 Dectape II tapes. Fit, bit tight but
fit.
Drive works great! And some of the stuff I wrote in the 1980's.... Old
posts to compuserve's pdp11 forum, ancient bitnet messages, stuff about
getting the pdp8/L and passing up other stuff... Could have bought a
Vax730 with R80/RL02 for 3k but didn't have the money.
All in all a fun trip down memory lane. And I kept thinking "Was I
really that naive?
C
On 1/10/2023 6:18 PM, Sellam Abraham via cctalk wrote:
Yes, the 2/2P models I [think I] had were blue.
Sellam
On Tue, Jan 10, 2023 at 2:21 PM Fred Cisin via cctalk <
cctalk(a)classiccmp.org>
wrote:
>>> A few years later, I got a used ["Euro"]-Apple II, converted for
USA
>>> use, in an OSI Challenger case (with wood (walnu?) sides), with an
>>> external RCA keyboard.
>>> If you didn't get it, then maybe Eric Smith?
>
> On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
>> Was it this style (Challenger 4P)?
>>
>
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
>> I can't remember if I ever had a 4P
but I did have I think two 2 or 2P
>> models.
>> Either way, I'm not sure if I got any from you, but in the end, if I
did,
>> you know what happened.
>> I do still have a Challenger motherboard around here somewhere, as well
> as
>> I think an OSI of some model in a custom-built big-box style enclosure.
>
> Yes, it was that style, but BLUE
> No floppy unit.
> The external RCA keyboard was black, and a splash resistant case.
>
11 Jan
11 Jan
6:16 a.m.
The belts that I use for TU58's work but are a bit on the tight side.
I'd say buy a set of those, and also a set that is is 1.5 times the size
and twice as wide. It's not that big of a deal, technically it may cause
a bit more stress to the sleeve bearings and cause them to wear out in
20 years as opposed to 50. Oh well :-)
C
On 1/11/2023 1:22 AM, Sellam Abraham via cctalk wrote:
I had the same issue with one of those drives. I
think I may have it but I
need to source a belt to fix it. The black goop that used to be the belt
got all over the mechanism. It was a pain to clean off completely.
Sellam
On Tue, Jan 10, 2023 at 10:11 PM Chris Zach via cctalk <
cctalk(a)classiccmp.org> wrote:
> Speaking of reading old floppies, I got my Model 100 and Tandy Portable
> Disk Drive down from the shelf to read some old floppies I found from
> the 1980's. 3.5 inch disks with a whopping 100k capacity each!
>
> Problem was drive was saying the disks were "not formatted". Took it
> apart, found that the belt had literally turned to black goo and wrapped
> itself around the capstain. Cleaned it off (took forever), then put on a
> new modern belt that I use for TU58 Dectape II tapes. Fit, bit tight but
> fit.
>
> Drive works great! And some of the stuff I wrote in the 1980's.... Old
> posts to compuserve's pdp11 forum, ancient bitnet messages, stuff about
> getting the pdp8/L and passing up other stuff... Could have bought a
> Vax730 with R80/RL02 for 3k but didn't have the money.
>
> All in all a fun trip down memory lane. And I kept thinking "Was I
> really that naive?
>
> C
>
> On 1/10/2023 6:18 PM, Sellam Abraham via cctalk wrote:
>> Yes, the 2/2P models I [think I] had were blue.
>>
>> Sellam
>>
>> On Tue, Jan 10, 2023 at 2:21 PM Fred Cisin via cctalk <
> cctalk(a)classiccmp.org>
>> wrote:
>>
>>>>> A few years later, I got a used ["Euro"]-Apple II,
converted for USA
>>>>> use, in an OSI Challenger case (with wood (walnu?) sides), with an
>>>>> external RCA keyboard.
>>>>> If you didn't get it, then maybe Eric Smith?
>>>
>>> On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
>>>> Was it this style (Challenger 4P)?
>>>>
>>>
>
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
>>>> I can't remember if I ever had a 4P but I did have I think two 2 or
2P
>>>> models.
>>>> Either way, I'm not sure if I got any from you, but in the end, if I
> did,
>>>> you know what happened.
>>>> I do still have a Challenger motherboard around here somewhere, as well
>>> as
>>>> I think an OSI of some model in a custom-built big-box style enclosure.
>>>
>>> Yes, it was that style, but BLUE
>>> No floppy unit.
>>> The external RCA keyboard was black, and a splash resistant case.
>>>
>
10 Jan
10 Jan
3:24 p.m.
I haven't seen any mention of greaseweazel types of "flux" readers. They
read the flux changes off of the floppy and then interpret them with a
separate program.
I use this to analyze DEC RX01 & RX02 8" floppies.
I know it works with FM, MFM and GCR disks as well as single and double
sided diskettes.
On 1/10/2023 4:20 PM, Fred Cisin via cctalk wrote:
> A few
years later, I got a used ["Euro"]-Apple II, converted for USA
> use, in an OSI Challenger case (with wood (walnu?) sides), with an
> external RCA keyboard.
> If you didn't get it, then maybe Eric Smith?
On Tue, 10 Jan 2023, Sellam Abraham via cctalk wrote:
Was it this style (Challenger 4P)?
https://imgs.search.brave.com/p_LUazpNEKMRJwuHl-uqgVmE7lVt1-7AodxQMTSCvOY/r…
I can't remember if I ever had a 4P but I did have I think two 2 or 2P
models.
Either way, I'm not sure if I got any from you, but in the end, if I
did,
you know what happened.
I do still have a Challenger motherboard around here somewhere, as
well as
I think an OSI of some model in a custom-built big-box style enclosure.
Yes, it was that style, but BLUE
No floppy unit.
The external RCA keyboard was black, and a splash resistant case.
3:44 p.m.
On Tue, 10 Jan 2023, Fred Cisin wrote:
So, a flux transition board might work,
(for OSI
disks)
On Tue, 10 Jan 2023, Mike Katz wrote:
I haven't seen any mention of greaseweazel types
of "flux" readers. They
read the flux changes off of the floppy and then interpret them with a
separate program.
I use this to analyze DEC RX01 & RX02 8" floppies.
I know it works with FM, MFM and GCR disks as well as single and double
sided diskettes.
Well, the original post that started this thread was primarily about
cleaning the heads of the drive being used, with reading being done by
essentially the same hardware that wrote them. (NOT OSI disks)
Disk head cleaning would be about the same when using a flux transition
board, as when using the original system. Possibly very minor issues, in
terms of how many revolutions end up being needed for each successful
track read.
I think that a flux transition system would seem be appropriate for the
OSI disks. Although, it would be good to hear from anybody who has read
OSI disks. (are there any OTHER differences that need to be taken into
account?)
At one time, I speculated whether a flux transition system could be used
to read the second side of a flippy disk without flipping it. Or, reading
the second side of a double sided disk in a single sided drive, by
flipping it. But, then I remembered/realized that double sided drive
heads are physically radially offset from each other.
11 Jan
11 Jan
12:39 a.m.
On 1/10/23 15:24, Mike Katz via cctalk wrote:
I haven't seen any mention of greaseweazel types
of "flux" readers.
They read the flux changes off of the floppy and then interpret them
with a separate program.
Before the greaseweazel, and similar boards, there
were the Catweasel
controllers, which are essentially the same thing, but done in an FPGA
with an ISA interface. Even then, I kept telling people that most
microcontrollers with a capture-mode timer would do the job for a
fraction of the cost. Personally, I've been using an STM32F407 with
my own software. It produces catweasel-files and works with my own
code written for catweasel.
I probably made it overly complicated, as it uses DMA to record the
capture events. At 168MHz on a pipelined architecture, I could have
gone with polled I/O, but the deed is done.
Even before the high-integration MCUs with everything but the kitchen
sink, I was using an ATMega162 with external SRAM to do the sampling.
It's not brain surgery.
Chuck
9 Jan
9 Jan
11:19 a.m.
On Mon, Jan 9, 2023, 10:23 AM Warner Losh via cctalk <cctalk(a)classiccmp.org>
wrote:
On Sun, Jan 8, 2023, 6:29 PM Zane Healy via cctalk
<cctalk(a)classiccmp.org>
wrote:
Also, a normal USB Floppy drive can only handle 1.44MB formatted floppies.
720k might work (but there is nothing in the standards to describe this)
and oddball formats are right out.
Warner
https://www.usb.org/sites/default/files/usbmass-ufi10.pdf
USB Mass Storage Class – UFI Command Specification Revision 1.0
4.10.2 Formattable Capacity Descriptors
The UFI device supports the following capacity descriptors.
Table 35 - Capacity Descriptors Supported by USB-FDU
DD 720 KB
HD 1.25 MB (1024-byte sectors)
HD 1.44 MB
11:38 a.m.
On Mon, Jan 9, 2023 at 12:19 PM Glen Slick via cctalk <cctalk(a)classiccmp.org>
wrote:
On Mon, Jan 9, 2023, 10:23 AM Warner Losh via cctalk
<
cctalk(a)classiccmp.org>
wrote:
Indeed... I had a memory of it not doing even the 720k drives, but either I
found an old copy of the standard years ago when I was looking at this, or
I just misremembered no support for 5.25" floppies at all as only
supporting 1.44MB HD format...
Thanks for the correction...
Warner
On Sun, Jan 8, 2023, 6:29 PM Zane Healy via
cctalk <
cctalk(a)classiccmp.org>
wrote:
Also, a normal USB Floppy drive can only handle 1.44MB formatted
floppies.
720k might work (but there is nothing in the
standards to describe this)
and oddball formats are right out.
Warner
https://www.usb.org/sites/default/files/usbmass-ufi10.pdf
USB Mass Storage Class – UFI Command Specification Revision 1.0
4.10.2 Formattable Capacity Descriptors
The UFI device supports the following capacity descriptors.
Table 35 - Capacity Descriptors Supported by USB-FDU
DD 720 KB
HD 1.25 MB (1024-byte sectors)
HD 1.44 MB
11:44 a.m.
On Jan 9, 2023, at 11:19 AM, Glen Slick via cctalk <cctalk(a)classiccmp.org> wrote:
https://www.usb.org/sites/default/files/usbmass-ufi10.pdf
USB Mass Storage Class – UFI Command Specification Revision 1.0
4.10.2 Formattable Capacity Descriptors
The UFI device supports the following capacity descriptors.
Table 35 - Capacity Descriptors Supported by USB-FDU
DD 720 KB
HD 1.25 MB (1024-byte sectors)
HD 1.44 MB
I think any 800KB Mac floppies I’d have, have already been imaged (on my PowerMac 8500/180
in 1999). I’ve successfully read a 720KB floppy.
Both USB Floppy drives I have are pretty old, the one I’m using is the newer of the two,
and even it is about 22 years old.
Zane
715
days inactive
717
days old
42 comments
15 participants
participants (15)
-
Chris Zach -
Chuck Guzis -
Doc Shipley -
Fred Cisin -
Glen Slick -
Grant Taylor -
Liam Proven -
Mike Katz -
nico de jong -
Paul Koning -
Sellam Abraham -
skogkatt007＠yahoo.com -
Van Snyder -
Warner Losh -
Zane Healy