6 Jun
2007
6 Jun
'07
12:30 p.m.
--------Original Message:
Date: Wed, 6 Jun 2007 08:34:37 -0500
From: "Dave Dunfield" <dave06a at dunfield.com>
Subject: Re: TESTFDC usage
<snip>
To completely test the FDC, you need to check Single, Double and
Double/128 at each of 250, 300 and 500 kbps rates. These are
represented in a standard PC at:
250 = 5.25 low-density drive only, 3.5" low-density diskette
300 = 5.25 Low-density diskette in high-density drive
500 = 5.25" or 2.5" high-density diskette
So to check all possible data rates without a 300/360 modded drive,
you need to run two tests - either the 5.25" LD and HD drives, or a
5.25" HD and 3.5" drive.
----------------------
I also wanted to do some testing but, despite our off-list correspondence,
I'm still confused:
5.25" drive, 3.5" diskette ???
2.5" diskette ???
3.5" drive - LD or HD?
Exactly what tests should be run with what size/density disk in what size/
density/speed drive in order to get a complete picture?
mike
6 Jun
6 Jun
3:20 p.m.
Date: Wed, 6 Jun 2007 08:34:37 -0500
From: "Dave Dunfield" <dave06a at dunfield.com>
Subject: Re: TESTFDC usage
<snip>
To completely test the FDC, you need to check Single, Double and
Double/128 at each of 250, 300 and 500 kbps rates. These are
represented in a standard PC at:
250 = 5.25 low-density drive only, 3.5" low-density diskette
300 = 5.25 Low-density diskette in high-density drive
500 = 5.25" or 2.5" high-density diskette
So to check all possible data rates without a 300/360 modded drive,
you need to run two tests - either the 5.25" LD and HD drives, or a
5.25" HD and 3.5" drive.
----------------------
I also wanted to do some testing but, despite our off-list correspondence,
I'm still confused:
5.25" drive, 3.5" diskette ???
Either a 5.25" low density drive (and it should be obvious which type
of diskette you need to use with it) - OR -
a 3.5" low-density diskette in either type of 3.5" drive (no I am not
trying to tell you to put a 3.5" diskette into a 5.25" drive)
2.5" diskette ???
Humm.... 5,25" or 2.5" ... obviously the 2.5 is a typo, so it must have
been either:
5.25" or 5.25"
-or- 5.25" or 3.5"
I wonder which one it could be...
Basically, testing HD in either type of drive (with HD diskette) will
test 500kbps.
3.5" drive - LD or HD?
Let me try to explain it all.
All 3.5" drives turn at 300rpm.
to get DD a data rate of 250kbps is used.
to get HD a data rate of 500kbps is used (HD drive only).
- When doing DD, it DOES NOT MATTER what type the 3.5" drive is,
the data rate, rotation speed and head width are all exactly the
same ... this is why 3.5" HD drives do not have the compatibility
problems with DD media sometimes observed with 5.25" HD drives.
All 5.25" low-density drives turn at 300rpm.
to get DD a data rate of 250kbps is used.
HD is not applicable.
Almost-All PC 5.25" high-density drives turn at 360rpm.
to get DD a data rate of 300kbps is used (note1)
to get HD a data rate of 500kbps is used (note2)
note1: 300kbps at 360rpm works out to exactly the same bit
density as 250kbps at 300rpm - this is the "compatibility mode"
to allow single-speed 360rpm 5.25" drives to read/write DD diskettes.
note2: The HD data rate is 500kbps on both 3.5" and 5.25" drives. The
slower 3.5" (300 rpm) drives store more bits on a track, as it takes
longer for the whole track to pass under the head. This is the reason
that 3.5" HD disks store 1.44M which 5.25" HD disks store 1.2M
note3: 360rpm / 500kbps is electrically the same as an 8" drive, which
is why it's fairly easy to replace 8" drives with 5.25" HD drives.
Exactly what tests should be run with what
size/density disk in what size/
density/speed drive in order to get a complete picture?
When I say "drive" I mean that exact type of drive.
When I say "diskette" I mean that type of diskette, and it
does not matter which type of drive (LD or HD) it is in - obviously it
has to be the same physical format as the diskette.
To test 250kbps rate, you need ONE of:
3.5" drive (either type) with 3.5" LOW DENSITY diskette.
5.25" LOW-DENSITY drive (with 5.25" LOW DENSITY diskette)
To test 300kpbs, you need:
5.25" HIGH-DENSITY drive with 5.25" LOW-DENSITY diskette
To test 500kbps, you need ONE of:
3.5" HIGH-DENSITY drive with 3.5" HIGH-DENSITY diskette.
5.25" HIGH-DENSITY drive with 5.25" HIGH-DENSITY diskette.
For most people, who have 3.5" and 5.25" HD drives, running
the full tests available for both those drive types will test
all the possible combinations (in fact it will test 500kbps
twice).
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
4:29 p.m.
On Wed, 6 Jun 2007, Dave Dunfield wrote:
All 3.5" drives turn at 300rpm.
Well, . . . ALMOST all. NEC ran some 3.5" drives at 360RPM. That
enabled them to have the same format specs for 8", 5.25", and 3.5"
That was a good, through explanation.
--
Grumpy Ol' Fred cisin at xenosoft.com
4:48 p.m.
Fred Cisin wrote:
On Wed, 6 Jun 2007, Dave Dunfield wrote:
Indeed. It needs to be put on its own web page somewhere so it can be
referenced. It's surprising how often the topic crops up (not just here, but
on any kind of vintage computing group)
All 3.5" drives turn at 300rpm.
Well, . . . ALMOST all. NEC ran some 3.5" drives at 360RPM. That
enabled them to have the same format specs for 8", 5.25", and 3.5"
That was a good, through explanation. 
5:11 p.m.
New subject: floppy issues was Re: TESTFDC usage
--- Jules Richardson <julesrichardsonuk at yahoo.co.uk>
wrote:
Indeed. It needs to be put on its own web page
somewhere so it can be
referenced. It's surprising how often the topic
crops up (not just here, but
on any kind of vintage computing group)
Now what would be nice is a *small* document that
would explain why rotational speeds and other things
matter, particularly when making/recreating images. A
catalog of different drive types and their issues
would go hand in hand w/such.
____________________________________________________________________________________
Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for
today's economy) at Yahoo! Games.
http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow
4:54 p.m.
On 6 Jun 2007 at 13:29, Fred Cisin wrote:
Well, . . . ALMOST all. NEC ran some 3.5"
drives at 360RPM. That
enabled them to have the same format specs for 8", 5.25", and 3.5"
I've got a couple of very neat Toshiba 3.5" drives that auto-adjust
rotational speed. You can't format a 1.3MB 360 RPM floppy but you
can read and write one.
Many USB floppies as well as the Imation Superdrive will do the same--
i.e. read/write, but no format.
Cheers,
Chuck
5:17 p.m.
On 06/06/2007 21:29, Fred Cisin wrote:
On Wed, 6 Jun 2007, Dave Dunfield wrote:
And some early Sony 3.5" drives turn at 600 rpm, using twice the normal
data rate. But they have a different interface pinout as well, so
you're unlikely to see them in a PC.
--
Pete Peter Turnbull
Network Manager
University of York
All 3.5" drives turn at 300rpm.
Well, . . . ALMOST all. NEC ran some 3.5" drives at 360RPM. That
enabled them to have the same format specs for 8", 5.25", and 3.5"
5:33 p.m.
what about the Sony drives that appeared in the SMC-70
series? Can't we talk about them for a bit? I was
under the impression neither set (one in an SMC-70,
another in an SMC-70C) worked, but then I remembered
that these computers have sort of a mode switch, one
setting makes the puter boot from the drives, so maybe
that was my problem.
Has anyone played with these? Could those units take
a standard 3.5" drive?
--- Pete Turnbull <pete at dunnington.plus.com> wrote:
On 06/06/2007 21:29, Fred Cisin wrote:
____________________________________________________________________________________
We won't tell. Get more on shows you hate to love
(and love to hate): Yahoo! TV's Guilty Pleasures list.
http://tv.yahoo.com/collections/265
On Wed, 6 Jun 2007, Dave Dunfield wrote:
at 360RPM. That
All 3.5" drives turn at 300rpm.
Well, . . . ALMOST all. NEC ran some 3.5" drives enabled them to have the same format specs for
8",
5.25", and 3.5"
And some early Sony 3.5" drives turn at 600 rpm,
using twice the normal
data rate. But they have a different interface
pinout as well, so
you're unlikely to see them in a PC.
--
Pete Peter Turnbull
Network Manager
University of York
7 Jun
7 Jun
6:27 p.m.
Hi,
HP used them _a lot_, bot hthe signle-head and double-head versions.
AFAIK they were actually 80 cylinder drives, with the normal 135tpi
spacing. Certainly on the double-head ones, HP formatted 77 user
cylinders, the last 3 were reserved for replacements for bad blocks, the
bad block map, etc.
There as a later Sony drive, also 600rpm, that HP put in the 9114B and,
IIRC, 9153. This is a half-height unit, with many parts in common with the
Apple 800K drive (head carriage, stepper motor, motor control ICs,
analogue ASIC, etc). The version that HP used has a single 34 pin
conenctor, pinout very similar to an SA400 (and thus a PC drive), but
with power on some of the odd-numbered pins. But from the scheamtics,
it's clear that moving soldered links would make all those odd-numbered
pins ground, and there is a place on the PCB for a normal 4 pin power
connector.
Be warned that the oldder, full-height models have a nasty problem. The
grease on the eject mechanusm goes hard with age, and this then doesn't
latch properly,. On a double-head drive, the upper head can then get
caught in the disk shutter when you eject the disk. It's possible to rip
the head right off the gimbal spring.
If you have one of the older drives, you might want to look for the
recent articles about erparing the HP9114 drive on the forum at
http://www.hpmuseum.org . There's a link from one of them to a document
on repairing the 9114, the last part of that docuemnt is an article I
wrote on taking the drive apart and cleaning off the grease.
-tony
And some early Sony 3.5" drives turn at 600
rpm, using twice
the normal data rate....
I'd forgotten about those, they were used in the Apricot PC and PC/Xi. ISTR
they were 70 track devices too.
6:58 p.m.
On 7 Jun 2007 at 23:27, Tony Duell wrote:
AFAIK they were actually 80 cylinder drives, with the
normal 135tpi
spacing. Certainly on the double-head ones, HP formatted 77 user
cylinders, the last 3 were reserved for replacements for bad blocks, the
bad block map, etc.
...and there were also the 300 RPM 40 cylinder 3.5" DS2D drives at
67.5 tpi, used on a few CP/M systems as well as many inexpensive word
processors.
There were also some 600 RPM Sony 67.5 tpi SS drives. I think the
Preis boxes used them.
Cheers,
Chuck
7:08 p.m.
On Thu, 7 Jun 2007, Chuck Guzis wrote:
...and there were also the 300 RPM 40 cylinder
3.5" DS2D drives at
67.5 tpi, used on a few CP/M systems as well as many inexpensive word
processors.
used by the Epson Geneva/PX8
There were also some 600 RPM Sony 67.5 tpi SS drives.
I think the
Preis boxes used them.
. . . and what was in the Tandy portable disk drive #1 for the model 100?
8 Jun
8 Jun
10:18 a.m.
Rumor has it that Fred Cisin may have mentioned these words:
. . . and what was in the Tandy portable disk drive #1
for the model 100?
Dunno the drive manufacturer, but I can tell you it was SS/SD, either
40track (TPDD1) or 80 track (TPDD2), with two sectors of 1280 bytes each
IIRC, thereby getting 100K or 200K storage respectively.
Laterz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger -- SysAdmin, Iceberg Computers
zmerch at 30below.com
Hi! I am a .signature virus. Copy me into your .signature to join in!
6:08 p.m.
On Thu, 7 Jun 2007, Chuck Guzis wrote:
Ah yes, the PF10. Now that was a strange drive. There's one PCB inside
that contains the control processor (6303 IIRC), EPROM, RAM, disk
controller chip _and_ the head amplifier, stepper drivers, etc. There's
no separate drive logic board.
And yes, it's 67.5 TPI.
-tony
...and there were also the 300 RPM 40 cylinder
3.5" DS2D drives at
67.5 tpi, used on a few CP/M systems as well as many inexpensive word
processors.
used by the Epson Geneva/PX8
6 Jun
6 Jun
7:17 p.m.
On Wed, 6 Jun 2007, Dave Dunfield wrote:
Well... I hoped it would be obvious, but that discussion was specifically
about what you are likely to find on a PC - I have never encountered a
3.5" drive on a PC that runs at anything other than 300 rpm (although I
fully agree that such a thing could have been done - but I don't think
you are very likely to run across one). I saw no value in expounding on
all the things you won't have to deal with with TESTFDC - just the ones
you are likely to find.
I did say "Almost all" for 5.25" HD drives and 360rpm, because I have
found references to dual speed drive implementations on PC compatible
machines, although I don't think I have personally encountered one.
All 3.5" drives turn at 300rpm.
Well, . . . ALMOST all. NEC ran some 3.5" drives at 360RPM. That
enabled them to have the same format specs for 8", 5.25", and 3.5" That was a good, through explanation.
Thanks.
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
11:52 p.m.
On Wednesday 06 June 2007 15:20, Dave Dunfield wrote:
So Dave, what's the deal with those oddball 5.25" drives? I'm remembering
vaguely some that were 96tpi, and one (?) that was supposedly 100tpi...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Date: Wed, 6
Jun 2007 08:34:37 -0500
From: "Dave Dunfield" <dave06a at dunfield.com>
Subject: Re: TESTFDC usage
<snip>
To completely test the FDC, you need to check Single, Double and
Double/128 at each of 250, 300 and 500 kbps rates. These are
represented in a standard PC at:
250 = 5.25 low-density drive only, 3.5" low-density diskette
300 = 5.25 Low-density diskette in high-density drive
500 = 5.25" or 2.5" high-density diskette
So to check all possible data rates without a 300/360 modded drive,
you need to run two tests - either the 5.25" LD and HD drives, or a
5.25" HD and 3.5" drive.
----------------------
I also wanted to do some testing but, despite our off-list
correspondence, I'm still confused:
5.25" drive, 3.5" diskette ???
Either a 5.25" low density drive (and it should be obvious which type
of diskette you need to use with it) - OR -
a 3.5" low-density diskette in either type of 3.5" drive (no I am not
trying to tell you to put a 3.5" diskette into a 5.25" drive)
2.5" diskette ???
Humm.... 5,25" or 2.5" ... obviously the 2.5 is a typo, so it must have
been either:
5.25" or 5.25"
-or- 5.25" or 3.5"
I wonder which one it could be...
Basically, testing HD in either type of drive (with HD diskette) will
test 500kbps.
3.5" drive - LD or HD?
Let me try to explain it all.
All 3.5" drives turn at 300rpm.
to get DD a data rate of 250kbps is used.
to get HD a data rate of 500kbps is used (HD drive only).
- When doing DD, it DOES NOT MATTER what type the 3.5" drive is,
the data rate, rotation speed and head width are all exactly the
same ... this is why 3.5" HD drives do not have the compatibility
problems with DD media sometimes observed with 5.25" HD drives.
All 5.25" low-density drives turn at 300rpm.
to get DD a data rate of 250kbps is used.
HD is not applicable.
Almost-All PC 5.25" high-density drives turn at 360rpm.
to get DD a data rate of 300kbps is used (note1)
to get HD a data rate of 500kbps is used (note2)
note1: 300kbps at 360rpm works out to exactly the same bit
density as 250kbps at 300rpm - this is the "compatibility mode"
to allow single-speed 360rpm 5.25" drives to read/write DD diskettes.
note2: The HD data rate is 500kbps on both 3.5" and 5.25" drives. The
slower 3.5" (300 rpm) drives store more bits on a track, as it takes
longer for the whole track to pass under the head. This is the reason
that 3.5" HD disks store 1.44M which 5.25" HD disks store 1.2M
note3: 360rpm / 500kbps is electrically the same as an 8" drive, which
is why it's fairly easy to replace 8" drives with 5.25" HD drives.
Exactly what tests should be run with what
size/density disk in what
size/ density/speed drive in order to get a complete picture?
When I say "drive" I mean that exact type of drive.
When I say "diskette" I mean that type of diskette, and it
does not matter which type of drive (LD or HD) it is in - obviously it
has to be the same physical format as the diskette.
To test 250kbps rate, you need ONE of:
3.5" drive (either type) with 3.5" LOW DENSITY diskette.
5.25" LOW-DENSITY drive (with 5.25" LOW DENSITY diskette)
To test 300kpbs, you need:
5.25" HIGH-DENSITY drive with 5.25" LOW-DENSITY diskette
To test 500kbps, you need ONE of:
3.5" HIGH-DENSITY drive with 3.5" HIGH-DENSITY diskette.
5.25" HIGH-DENSITY drive with 5.25" HIGH-DENSITY diskette.
For most people, who have 3.5" and 5.25" HD drives, running
the full tests available for both those drive types will test
all the possible combinations (in fact it will test 500kbps
twice).
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
7 Jun
7 Jun
1:07 a.m.
On Wed, 6 Jun 2007, Roy J. Tellason wrote:
So Dave, what's the deal with those oddball
5.25" drives? I'm remembering
vaguely some that were 96tpi, and one (?) that was supposedly 100tpi...
Dave is testing the FDC, not the physical parameters of the drive.
96tpi DSDD was common briefly, but was never used in the PC, except for
the PC-JX. To the disk controller, it is the same as a 3.5" "720K".
Teac 55F, Shugart 465, Tandon TM100-4, Mitsubishi 4853, etc
Micropolis came out with a 100tpi (77 track) 5.25" drive. It never really
caught on. Tandon made a replacement drive for that - TM100-4M.
With a few exceptions, the 96tpi formats cqan be done using a 1.2M drive.
Teac 55FG is deliberately intende3d for both "720K" and 1.2M use.
The only exceptions would be drive where the stepper switches to double
stepping when in "low density" mode, or using a 250K or 300K data transfer
rate.
--
Grumpy Ol' Fred cisin at xenosoft.com
9 Jun
9 Jun
1:53 p.m.
On Thursday 07 June 2007 01:07, Fred Cisin wrote:
On Wed, 6 Jun 2007, Roy J. Tellason wrote:
Ok...
So Dave, what's the deal with those oddball
5.25" drives? I'm
remembering vaguely some that were 96tpi, and one (?) that was
supposedly 100tpi...
Dave is testing the FDC, not the physical parameters of the drive. 96tpi DSDD was common briefly, but was never used in
the PC, except for
the PC-JX. To the disk controller, it is the same as a 3.5" "720K".
Teac 55F, Shugart 465, Tandon TM100-4, Mitsubishi 4853, etc
Micropolis came out with a 100tpi (77 track) 5.25" drive. It never really
caught on. Tandon made a replacement drive for that - TM100-4M.
I *think* that CBM used one in one of their boxes too, maybe the 8050? It's
been a while so I'd have to double-check that to be sure...
With a few exceptions, the 96tpi formats cqan be done
using a 1.2M drive.
Teac 55FG is deliberately intende3d for both "720K" and 1.2M use.
The only exceptions would be drive where the stepper switches to double
stepping when in "low density" mode, or using a 250K or 300K data transfer
rate.
Noted.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
7 Jun
7 Jun
9:10 a.m.
So Dave, what's the deal with those oddball
5.25" drives? I'm remembering
vaguely some that were 96tpi, and one (?) that was supposedly 100tpi...
The commonly found 5.25" drives are:
A: Single-Sided, 35 track, 48 tpi (original SA400)
B: Single-Sided, 40 track, 48 tpi (SA400L and others)
C: Double-sided, 40 track, 48 tpi (SA450, TM-100-2, TEAC55B, etc.)
D: Double-sided, 80 track, 96 tpi (SA460, TM-100-4 TEAC55F, etc.)
E: Double-sided, 80 track, 96 tpi, High Density (TEAC55G, Pan JU-475 etc.)
Less common, but I've run into a couple are:
F: Single-Sided, 80 track, 96 tpi (can't think of any models)
Still (much) less common are:
G: Double-Sided, 77 track, 100tpi (TM-100-4M)
A, B and C are compatible within the areas that they overlap,
ie: C can read/write B and A, and B can read/write A
D and F are compitible within the areas that they overlap
(ie, side1), and can be "mostly" compatible with A, B and C
within the areas that they overlap by double-stepping (ie: the
even 96tpi tracks line up with the 48tpi drive tracks. There
is an issue with the head being "thinner" which can cause
some incompatibilities when disks are written on a 48 tpi
drive, then re-written on a 96tpi drive, and then read on
a 48 tpi drive - this is due to remanents of the original
pattern remaining at the edges after a thinner track is laid
down by the 96tpi drive head causing confusion when it's read
back with the wider 48tpi drive head.
E can be compatible with D and F within the areas that they
overlap provided it is run at low-density and 300rpm, or
360rpm with a modified data rate. It can also be compatible
with A, B and C by the use of double stepping.
G is incompatible with all others, because the 100 tpi tracks
have a different spacing and therefore you cannot position
the head over all tracks of a 48 or 96 tpi written diskette.
Make sense?
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
3:04 p.m.
On Thu, 7 Jun 2007, Dave Dunfield wrote:
F: Single-Sided, 80 track, 96 tpi (can't think of
any models)
TM100-3
What does DEC use for that?
Still (much) less common are:
G: Double-Sided, 77 track, 100tpi (TM-100-4M)
which existed primarily as a
replacement for the Micropolis 100tpi.
The Micropolis 5.25" drives were very reliable, but used a helical lead
screw, which made them kinda slow.
3:22 p.m.
On 7 Jun 2007 at 12:04, Fred Cisin wrote:
Let's not forget single-sided 77 track 100 tpi (Micropolis 1015 and
1016). In construction, the antithesis of the SA-400. Built like a
brick latrine.
--Chuck
Still (much)
less common are:
G: Double-Sided, 77 track, 100tpi (TM-100-4M)
which existed primarily as a
replacement for the Micropolis 100tpi.
The Micropolis 5.25" drives were very reliable, but used a helical lead
screw, which made them kinda slow. 
6231
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