How to change Teac Floppy to 40 Tracks?

[Jürgen Strobel]

Hy NG,
i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
I have changed it to use 300RPM for 720KB 80 Tracks double sided; single
Step
Is there a posibility to get the Floppy doing double step for using it as a
40 Track Floppy Drive?
I know that on old Teac Drives there was the possibility to do this by
soldering out a Resistor or cut a line...
Thanks for your help
Juergen

[n***@nouce.bellatlantic.net]

Post by Jürgen Strobel
Hy NG,
i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
I have changed it to use 300RPM for 720KB 80 Tracks double sided; single
Step
Is there a posibility to get the Floppy doing double step for using it as a
40 Track Floppy Drive?
I know that on old Teac Drives there was the possibility to do this by
soldering out a Resistor or cut a line...
Thanks for your help
Juergen

Sorry no, it's a mechanical thing. The stepper, the rack and head
width are setup so that the 80tracks occupy about an inch for that
drive. A 40 track drive is set up with differnt stepper, rack heads
are different.

you can double step the drive so it reads 40 track disks but writing
media that way can be unreliable when read on 40tr drive.

What you really want is a TEAC FD55BR or similar. That would be an
older half height 40 track and those were commonly use in XT class PCs
and 286 At class machines as well.

Allison

[Herb Johnson]

Post by n***@nouce.bellatlantic.net

Post by Jürgen Strobel
Is there a posibility to get the Floppy doing double step for using it as a
40 Track Floppy Drive?
Juergen

Sorry no, it's a mechanical thing. The stepper, the rack and head
width are setup so that the 80tracks occupy about an inch for that
drive. A 40 track drive is set up with differnt stepper, rack heads
are different.
you can double step the drive so it reads 40 track disks but writing
media that way can be unreliable when read on 40tr drive.
Allison

Just a follow-up on Allison's remarks. The reason that 80-track drives
write unreliable 40-track diskettes, is that the 80-track 1.2M drives
create
a narrower (thinner) track of data on the diskette. The 40-track drives
which may read those disks will get less signal from the narrower
track. (They
designed the tracks to be thinner to get 80 tracks in the same space as
40.)

Herb Johnson

Herbert R. Johnson, voice 609-771-1503, New Jersey USA
<a href="http://retrotechnology.com/herbs_stuff"> web site</a>
<a href="http://retrotechnology.net/herbs_stuff"> domain mirror</a>
** ***@njcc.com and njcc.com/~hjohnson are EXPIRED **
my email address: herbjohnson ATT comcast DOTT net
if no reply, wait & try: hjohnson AAT retrotechnology DOTT com
"Herb's Stuff": old Mac, SGI, 8-inch floppy drives
S-100 IMSAI Altair computers, docs, by "Dr. S-100"


Herb Johnson

[Anonymous Guy]

Post by Herb Johnson
Just a follow-up on Allison's remarks. The reason that 80-track
drives write unreliable 40-track diskettes, is that the 80-track
1.2M drives create a narrower (thinner) track of data on the
diskette. The 40-track drives which may read those disks will
get less signal from the narrower track. (They designed the
tracks to be thinner to get 80 tracks in the same space as 40.)
Herb Johnson

Plus, the recording bias frequency and current in 1.2 meg drives
is different from that of 360k drives -- owing to the difference
in magnetic coercivity between double-density and high-density
media.

Writing to a double-density disk in a high-density drive is
somewhat like recording to a standard-bias audio cassette with
the tape deck's selector switch set to 'Chrome/Metal.'

It'll work, but you probably won't be too pleased with the result.

[n***@nouce.bellatlantic.net]

On Mon, 25 Apr 2005 21:30:13 +0000 (UTC), "Anonymous Guy"

Post by Anonymous Guy
Plus, the recording bias frequency and current in 1.2 meg drives
is different from that of 360k drives -- owing to the difference
in magnetic coercivity between double-density and high-density
media.

Where in the world did you get that 80tr drives are all 1.2mb????

Further most of those 1.2mb drives can and do run at standard 80 track
speed and recording densities.

Post by Anonymous Guy
Writing to a double-density disk in a high-density drive is
somewhat like recording to a standard-bias audio cassette with
the tape deck's selector switch set to 'Chrome/Metal.'

Ah your still way out there. To start with there is no such thing as
a "double-density disk" and the 1.2mb were not DD they were
a completely different media.

Post by Anonymous Guy
It'll work, but you probably won't be too pleased with the result.

True for different reasons than stated.

Allison

[Anonymous Guy]

Post by n***@nouce.bellatlantic.net

Post by Anonymous Guy
Plus, the recording bias frequency and current in 1.2 meg drives
is different from that of 360k drives -- owing to the difference
in magnetic coercivity between double-density and high-density
media.

Where in the world did you get that 80tr drives are all 1.2mb????

To the best of my recollection, no one ever made that
particular allegation.

Post by n***@nouce.bellatlantic.net
Further most of those 1.2mb drives can and do run at standard 80
track speed and recording densities.

Ever replaced a double-density drive in a CP/M machine with a
high-density drive, Ally? If so, how'd it work out for you?

Post by n***@nouce.bellatlantic.net

Post by Anonymous Guy
Writing to a double-density disk in a high-density drive is
somewhat like recording to a standard-bias audio cassette with
the tape deck's selector switch set to 'Chrome/Metal.'

Ah your still way out there. To start with there is no such thing
as a "double-density disk"...

Oh. My mistake, then. And here, all this time, I'd been
thinking that those disks marked "DSDD" were "double-density
disks." Clearly, a silly error on my part.

Post by n***@nouce.bellatlantic.net
...and the 1.2mb were not DD they were a completely different
media.

Yes; that appears to have been alluded to in the first paragraph,
above.

Post by n***@nouce.bellatlantic.net

Post by Anonymous Guy
It'll work, but you probably won't be too pleased with the result.

True for different reasons than stated.
Allison

[n***@nouce.bellatlantic.net]

On Tue, 26 Apr 2005 15:02:51 +0000 (UTC), "Anonymous Guy"

Post by Anonymous Guy

Post by n***@nouce.bellatlantic.net
Where in the world did you get that 80tr drives are all 1.2mb????

To the best of my recollection, no one ever made that
particular allegation.

Use of the term in this thread.

Post by Anonymous Guy

Post by n***@nouce.bellatlantic.net
Further most of those 1.2mb drives can and do run at standard 80
track speed and recording densities.

Ever replaced a double-density drive in a CP/M machine with a
high-density drive, Ally? If so, how'd it work out for you?

Yes, I do it frequently. The NS* I'm testing with has two fd55BV
(48tpi) and two FD55GFR(96tpi). the latter dives wrok fine.
There is a caveat, the 96tpi drive without OS mods only use the first
40 tracks.

On my other S100crate the FDC can handle any drive connected
and For 5.25" it has a FD55BV(48tpi) and a FD55gfr(96tpi) . Those are
along with an 8" and 3.5" drive.

So the answer is yes they work for me very well.

Post by Anonymous Guy

Post by n***@nouce.bellatlantic.net

Post by Anonymous Guy
Writing to a double-density disk in a high-density drive is
somewhat like recording to a standard-bias audio cassette with
the tape deck's selector switch set to 'Chrome/Metal.'

Ah your still way out there. To start with there is no such thing
as a "double-density disk"...

Oh. My mistake, then. And here, all this time, I'd been
thinking that those disks marked "DSDD" were "double-density
disks." Clearly, a silly error on my part.

It is an error as those are the same magnetics as SSSD disks.
The only exceptions to that are 5.25 high corceivity media that
is exclusively for the 1.2mb recording and there is a difference
between 720k and 1.44m 3.5: floppies.

Ignoring hard sector vs soft sector there are actually few media:

8" Single sided double sided and hard sector are all the same
magnetics. There may be different envelopes and sector holes
punched.

5.25 media there are two different magnetics the nearly black
high corceivity media for 1.2mb operation and everything else.
Again there are a few variations over time for the envelope and
of course hard and soft sector flavors.

3.5" There are three flavors, 720k, 1.44m and 2.88m. It's my
understanding the first two are different though I've used 1.44
with the hole covered as 720/780k with no bad effects. This case
I suspect there is both a drive sense (the hole) and data rate
interrelation that must be accomodated and the media itself
is the same magnetics. I'd double check that. However the 2.88
is different for sure.

So a floppy media that does 5.25" DSDD also does SSSD and
the other way around regardless of the number of tpi or the drive
it's used in. I'd add that the only difference for single sided and
double was the quality of side two, "single sided" media there
was no guarentee though it was with rare exception usable.
I know that as damaged NS* meda for the single density
MDS I would punch a hole for sector window and flip them
as they only stored 90k. I still do that if the media is scratched
as it's scarce.



Allison

[Randy McLaughlin]

Post by n***@nouce.bellatlantic.net
On Tue, 26 Apr 2005 15:02:51 +0000 (UTC), "Anonymous Guy"

<snip>

Post by n***@nouce.bellatlantic.net

Post by Anonymous Guy
Ever replaced a double-density drive in a CP/M machine with a
high-density drive, Ally? If so, how'd it work out for you?

Yes, I do it frequently. The NS* I'm testing with has two fd55BV
(48tpi) and two FD55GFR(96tpi). the latter dives wrok fine.
There is a caveat, the 96tpi drive without OS mods only use the first
40 tracks.

<snip>

Post by n***@nouce.bellatlantic.net
Allison

Anyone that wants to use a 1.2mb drive as a "quad density" drive needs to do
a few things: Ground pin 2 and change the drive jumpers to be two-speed (so
it can run 360RPM instead of 300 RPM), notes describing this are available
on my website.

It's a fairly un-important point but NorthStar normally only handles 35
tracks not 40.

NorthStar also had strange definitions:

DSDD was referred to as quad density (35 cylinders - 70 tracks).
DSQD was referred to as extended density (80 cylinders - 160 tracks).

I mention this because if you are using 96tpi drives some versions of CP/M
can be configured by specifying 'X' as drive type (eXtended) with the
configuration program.

To my knowledge no NorthStar DOS ever handled anything but 35 tracks (single
or double sided). NorthStar originally packaged their controller with
Shugart's SA400 which only did 35 tracks. The SA400 was the first 5.25"
drive and when others developed compatible drives they extended the
mechanism to 40 tracks.

For anyone interested DSQD is quad-density as we know it today and NorthStar
referring to DSDD as quad density was just a marketing issue and they used
the term quad density before any 96tpi drives were available.


Randy
www.s100-manuals.com

[Jürgen Strobel]

This post might be inappropriate. Click to display it.

[Randy McLaughlin]

Post by Jürgen Strobel
If you mentioned the North Star Computer, i owned one in the mid 90th, with
a Full hight Floppy 5,25" and a 5MB Winchester Drive with a CPM 2.2 which
was graphics enhanced. It was a 64 KB Desktop machine with built in 10"
Monitor.
The Disk/Track Format was very strange and the North Star used
Hardsectored
Floppys.

<snip>

Today people may call it strange but you need to remember that NorthStar was
an early micro.

There were no standards so what ever you did was right.

<gossip mode>Supposedly they had a deal with Processor Technology to develop
an extended basic for the Helios/PTDOS. The Helios is notorious for the
delays in shipment, right before the notorios QC issues. Supposedly because
of the delays on Processor Technologies side NorthStar decided to get a
quick and dirty controller/OS to go with their basic. It makes sense when
you consider the quality of the basic compared to the OS and the timing.
Many SOL-20's that would have been sold with a Helios went with a NorthStar
controller instead.</gossip mode>

There is nothing wrong with hard sectoring, it is now considered odd only
because of the development of LSI disk controlers that were developed that
do soft-sectoring.


Randy
www.s100-manuals.com

[n***@nouce.bellatlantic.net]

Post by Jürgen Strobel
If you mentioned the North Star Computer, i owned one in the mid 90th, with
a Full hight Floppy 5,25" and a 5MB Winchester Drive with a CPM 2.2 which
was graphics enhanced. It was a 64 KB Desktop machine with built in 10"
Monitor.
The Disk/Track Format was very strange and the North Star used Hardsectored
Floppys.

What you describe is a NorthStar* Advantage. It's non-S100 and almost
compatable with the S100 version that went before it. They share a
common format and media. the OS for both is nearly the same.

I have one and it's a nice machine.

Allison

[n***@nouce.bellatlantic.net]

On Wed, 27 Apr 2005 12:00:33 -0500, "Randy McLaughlin"

Post by Randy McLaughlin
It's a fairly un-important point but NorthStar normally only handles 35
tracks not 40.

Nominally your right... however the controller is dumb enough that it
doesn't care and it's a trivial patch for more tracks. Under CP/M for
NS* MDS There are version that not only use 40 tracks even two sides
if the controller is DD.

Post by Randy McLaughlin
DSDD was referred to as quad density (35 cylinders - 70 tracks).
DSQD was referred to as extended density (80 cylinders - 160 tracks).

This was used by other S100 and non-s100 manufacturers befor the
advent of 1.2mb pc thing.

Post by Randy McLaughlin
To my knowledge no NorthStar DOS ever handled anything but 35 tracks (single
or double sided). NorthStar originally packaged their controller with
Shugart's SA400 which only did 35 tracks. The SA400 was the first 5.25"
drive and when others developed compatible drives they extended the
mechanism to 40 tracks.

Abosolutely true for the MDS single density versions. Later they
would for the DD go further than that. The base distributions were
all 35 track as the assumed drives were SA400 compatables.

There were many mods to the OS for more tracks, also CP/M version were
far more flexible and many offered more configureation options.

Allison

[glen herrmannsfeldt]

Anonymous Guy wrote:

(snip)

Post by Anonymous Guy
Plus, the recording bias frequency and current in 1.2 meg drives
is different from that of 360k drives -- owing to the difference
in magnetic coercivity between double-density and high-density
media.
Writing to a double-density disk in a high-density drive is
somewhat like recording to a standard-bias audio cassette with
the tape deck's selector switch set to 'Chrome/Metal.'
It'll work, but you probably won't be too pleased with the result.

I believe pin 2 is used to select the write current.

-- glen

[d***@hotmail.com]

Post by Herb Johnson
Just a follow-up on Allison's remarks. The reason that 80-track drives
write unreliable 40-track diskettes, is that the 80-track 1.2M drives
create
a narrower (thinner) track of data on the diskette. The 40-track drives
which may read those disks will get less signal from the narrower
track. (They
designed the tracks to be thinner to get 80 tracks in the same space as
40.)
Herb Johnson

Hi Herb
My experimenting seems to indicate that the problem is that
the 1.2M drives don't erase enough of the original 360K
signal. When I completely wipe a 360K disk with a magnet
and then format and write data from a 1.2M I have had no
issue on my 360K drives reading them. Once they have been
written on by a 360K drive and then rewritten from
a 1.2M, they always fail to read on a 360K. Many don't
realize that even a virgin disk from the package may have
test data written on it from a 360K drive. Bofore experimenting,
I personally erase it completely.
This is just my experience.
Dwight

[n***@nouce.bellatlantic.net]

Post by d***@hotmail.com
Hi Herb
My experimenting seems to indicate that the problem is that
the 1.2M drives don't erase enough of the original 360K
signal. When I completely wipe a 360K disk with a magnet
and then format and write data from a 1.2M I have had no
issue on my 360K drives reading them. Once they have been
written on by a 360K drive and then rewritten from
a 1.2M, they always fail to read on a 360K. Many don't
realize that even a virgin disk from the package may have
test data written on it from a 360K drive. Bofore experimenting,
I personally erase it completely.
This is just my experience.
Dwight

He stated why thats so. The so called 80 track drives are really
better called 96tpi. The TPI stand for tracks per inch. The 40 track
drives are 48 TPI. So without being fancy its easy to see that the 96
tpi drives use a head (its a compound read/write and erase) that
occupies a track width that is one half (that's .5, 1/2) that of the
48TPI drives. The result is the 98TPI head cannot erase the full
trackwidth of a 48TPI drive and will leave old recorderd residue
on either side.

That is why you have to bulk erase the media to make
it work.

The caveat is that even when you do that the recorded track is half as
wide and the 48tpi head reads it with reduced output (about 40%).
That can be unreliable on marginal drives.

Further socalled 1.2 drives are still capable of standard DD and when
used that way with standard media they are known as QD (quad density)
and are typically 512x9x80x2 (720k) or 512x10x80x2 (800k). Or plainly
put twice that of what a 40track can and usually does.


Allison

[Herb Johnson]

Post by n***@nouce.bellatlantic.net

Post by d***@hotmail.com
Hi Herb
My experimenting seems to indicate that the problem is that
the 1.2M drives don't erase enough of the original 360K
signal. When I completely wipe a 360K disk with a magnet
and then format and write data from a 1.2M I have had no
issue on my 360K drives reading them.

Allison responded: [with edits by Herb]

Post by n***@nouce.bellatlantic.net
He stated why thats so. The so called 80 track drives are really
better called 96tpi. The TPI stand for tracks per inch. The 40 track
drives are 48 TPI. So without being fancy its easy to see that the 96
tpi drives use a head (its a compound read/write and erase) that
occupies a track width that is one half (that's .5, 1/2) that of the
48TPI drives. The result is the 98TPI head cannot erase the full
trackwidth of a 48TPI drive and will leave old recorderd residue
on either side.
That is why you have to bulk erase the media to make
it work.
The caveat is that even when you do that the recorded track
[using the 96 TPI/80-track drive] is half as
wide and the 48tpi head [which] reads it [gets] reduced output
(about 40%). That can be unreliable on marginal drives.
Further so-called 1.2M drives are still capable of standard DD and

when

Post by n***@nouce.bellatlantic.net
used that way with standard [DD] media they are known as QD (quad

density)

Post by n***@nouce.bellatlantic.net
and are typically 512x9x80x2 (720k) or 512x10x80x2 (800k). Or

plainly

Post by n***@nouce.bellatlantic.net
put twice that of what a 40track can and usually does.
Allison

Herb posts:

..and there are, or were, 720K drives which while 80 track did NOT
support HD 1.2M format as they are older than that format and media.
They are the origin of the term "quad density".

Here's some numbers on those track widths, to make the point.
Dimensions of these are listed on my Web page at:

http://retrotechnology.com/herbs_stuff/drive.txt

40 track: Track width
before tunnel erase .013 inch
after erase .0124 inch
(.012, .33mm [.0129 inch] also reported)

80 track 720K: Track width
before tunnel erase .0065 inch
after erase "to not exceed .006 inch".


80 track 1.2M: Track width: .16 mm (.0063 inch), also .0061 inch

This subject comes up every year or two. Therefore I put it on
my Web site, with primary references for the data if anyone is
skeptical. If you want the drive manuals, I sell copies on my
site as well.

Herb Johnson

Herbert R. Johnson, voice 609-771-1503, New Jersey USA
<a href="http://retrotechnology.com/herbs_stuff"> web site</a>
<a href="http://retrotechnology.net/herbs_stuff"> domain mirror</a>
** ***@njcc.com and njcc.com/~hjohnson are EXPIRED **
my email address: herbjohnson ATT comcast DOTT net
if no reply, wait & try: hjohnson AAT retrotechnology DOTT com
"Herb's Stuff": old Mac, SGI, 8-inch floppy drives
S-100 IMSAI Altair computers, docs, by "Dr. S-100"

[John Elliott]

***@nouce.bellatlantic.net wrote:
: On Mon, 25 Apr 2005 08:18:44 +0200, "Jurgen Strobel" <***@odity>
: wrote:

:>i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
:>Is there a posibility to get the Floppy doing double step for using it as a
:>40 Track Floppy Drive?

: Sorry no, it's a mechanical thing. The stepper, the rack and head
: width are setup so that the 80tracks occupy about an inch for that
: drive. A 40 track drive is set up with differnt stepper, rack heads
: are different.

At least some Teac 80-track drives could be made to double-step on the
hardware level; I've got one that came out of a BBC Micro. Unfortunately
it's inside a PC at the moment so I can't see exactly where the switch was
soldered to the PCB.

[Jürgen Strobel]

I have a FD-55fv 13u and a fd-55fr 511u on both it is possible.
TIA
Juergen
"John Elliott" <***@seasip.demon.co.uk> schrieb im Newsbeitrag news:***@seasip.demon.co.uk...
| ***@nouce.bellatlantic.net wrote:
| : On Mon, 25 Apr 2005 08:18:44 +0200, "Jurgen Strobel" <***@odity>
| : wrote:
|
| :>i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
| :>Is there a posibility to get the Floppy doing double step for using it
as a
| :>40 Track Floppy Drive?
|
| : Sorry no, it's a mechanical thing. The stepper, the rack and head
| : width are setup so that the 80tracks occupy about an inch for that
| : drive. A 40 track drive is set up with differnt stepper, rack heads
| : are different.
|
| At least some Teac 80-track drives could be made to double-step on the
| hardware level; I've got one that came out of a BBC Micro. Unfortunately
| it's inside a PC at the moment so I can't see exactly where the switch was
| soldered to the PCB.
|
| --
| -------------
http://www.seasip.demon.co.uk/index.html --------------------
| John Elliott |BLOODNOK: "But why have you got such a long face?"
| |SEAGOON: "Heavy dentures, Sir!" - The Goon Show
|
:-------------------------------------------------------------------------)

[Axel Berger]

Post by n***@nouce.bellatlantic.net
you can double step the drive so it reads 40 track disks but writing
media that way can be unreliable when read on 40tr drive.

Not totally true. A new or bulk erased disk written on by an 80 track
drive can be read just fine. The problem only arises when a disk
written on by a genuine 40 track drive is overwritten in an 80 track
one and read by a 40 track.
The reason being that the wider head then sees both the narrow new
track and outside it remnants of the old wide one.

[Barry Watzman]

Double stepping was usually just done in software. MS-DOS will do it
automatically based on the diskette descriptor byte. The problem,
however, is that the track width (the width of the erase head and the
magnetic track that it lays down) is still very narrow. In particular,
it's not wide enough to erase the full width of a track placed on a
diskette by a "real" 40-track drive, which can cause a lot of problems
using such drives in this manner.

Post by Jürgen Strobel
Hy NG,
i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
I have changed it to use 300RPM for 720KB 80 Tracks double sided; single
Step
Is there a posibility to get the Floppy doing double step for using it as a
40 Track Floppy Drive?
I know that on old Teac Drives there was the possibility to do this by
soldering out a Resistor or cut a line...
Thanks for your help
Juergen

[Jürgen Strobel]

But why are these mods work on older Teac drives which have 720Kb 80Tracks
single Step mode...
I have two of them in my Amstrad CPC and they work very well on the 40 Track
mode. I have tested to read these disc (which i have written with the
80/40Track Drive) with a Chion 40 Track Floppy and a Teac 40 Tracks thing,
and it work very well, no read errors no problem ... and the discs are still
about 5 years old.

I have tested the 1,2 MB Floppy with programs who create a double Step out
of the Software, and i can write and read 40 Tracks Discs written with all
kind of drives. And the written discs are readable in all drives too...

On the old drives for example my FD55FV i have to cut the Resistor R19 (i
put a switch there) i can choose now 40 and 80 Tracks.

So are there any chances to get the drive do a double step?
TIA
Juergen
"Barry Watzman" <***@neo.rr.com> schrieb im Newsbeitrag news:***@neo.rr.com...
| Double stepping was usually just done in software. MS-DOS will do it
| automatically based on the diskette descriptor byte. The problem,
| however, is that the track width (the width of the erase head and the
| magnetic track that it lays down) is still very narrow. In particular,
| it's not wide enough to erase the full width of a track placed on a
| diskette by a "real" 40-track drive, which can cause a lot of problems
| using such drives in this manner.
|
|
| Jürgen Strobel wrote:
|
| > Hy NG,
| > i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
| > I have changed it to use 300RPM for 720KB 80 Tracks double sided; single
| > Step
| > Is there a posibility to get the Floppy doing double step for using it
as a
| > 40 Track Floppy Drive?
| > I know that on old Teac Drives there was the possibility to do this by
| > soldering out a Resistor or cut a line...
| > Thanks for your help
| > Juergen
| >
| >

[CBFalconer]

*** topposting fixed ***

Post by Barry Watzman

Post by Jürgen Strobel
i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
I have changed it to use 300RPM for 720KB 80 Tracks double sided;
single Step. Is there a posibility to get the Floppy doing double
step for using it as a 40 Track Floppy Drive? I know that on old
Teac Drives there was the possibility to do this by soldering out
a Resistor or cut a line...

Double stepping was usually just done in software. MS-DOS will do
it automatically based on the diskette descriptor byte. The
problem, however, is that the track width (the width of the erase
head and the magnetic track that it lays down) is still very narrow.
In particular, it's not wide enough to erase the full width of a
track placed on a diskette by a "real" 40-track drive, which can
cause a lot of problems using such drives in this manner.

Your best shot at making a double stepped disk on an 80 track drive
is to first bulk-erase the disk. This will reduce the cross-talk
from the bypassed track when used in a 40 track drive.

[Jürgen Strobel]

Hy, the problem is not to read or write the disk!
The Jumper Settings on this drive are set to 300 RPM and Low Desity to make
it possible to read/write DD Disks. Thats the official settings for this
drive when you do not want to use it in High Desnity Mode. If you use it
then you do not have to use HD-Disks, only DD-Disks work right in this mode.
I know the Tracks are not so wide as on a 40 Track Drive and the chance to
get a loss of Data is high. But it is the easiest way to copy between 80 and
40 Tracks without Software. The best way to copy sth. onto "this 40 Track"
Disks are to erase the whole disk in 80 T Mode and the copy datas on it in
40 T Mode. So you can read it in 40 T Drives. (Just tested all variations
with a software on the Amstrad which can double step, single step, change
the Track/secors etc... like 22 Disk on the PC).

So if is someone out there who now how to do the modification to use a
Switch for using 40/80Tracks please help.


"CBFalconer" <***@yahoo.com> schrieb im Newsbeitrag news:***@yahoo.com...
| *** topposting fixed ***
| Barry Watzman wrote:
| > Jürgen Strobel wrote:
| >
| >> i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
| >> I have changed it to use 300RPM for 720KB 80 Tracks double sided;
| >> single Step. Is there a posibility to get the Floppy doing double
| >> step for using it as a 40 Track Floppy Drive? I know that on old
| >> Teac Drives there was the possibility to do this by soldering out
| >> a Resistor or cut a line...
| >
| > Double stepping was usually just done in software. MS-DOS will do
| > it automatically based on the diskette descriptor byte. The
| > problem, however, is that the track width (the width of the erase
| > head and the magnetic track that it lays down) is still very narrow.
| > In particular, it's not wide enough to erase the full width of a
| > track placed on a diskette by a "real" 40-track drive, which can
| > cause a lot of problems using such drives in this manner.
|
| Your best shot at making a double stepped disk on an 80 track drive
| is to first bulk-erase the disk. This will reduce the cross-talk
| from the bypassed track when used in a 40 track drive.
|
| --
| "If you want to post a followup via groups.google.com, don't use
| the broken "Reply" link at the bottom of the article. Click on
| "show options" at the top of the article, then click on the
| "Reply" at the bottom of the article headers." - Keith Thompson
|
|

[Rolf Harrmann]

Hello Jürgen,

Post by Jürgen Strobel
i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
I have changed it to use 300RPM for 720KB 80 Tracks double sided; single

Look this Link http://www.teac.com/DSPD/catalog.htm

I hope these Link help You.


Regards
Rolf

Form Germany

Ask to the E-Mail ".News." remove.

[Jürgen Strobel]

Thanks, but it is the normal doku, where the "Dipswitches" are explained.
The 40 Track thing is a bit unofficial, and need to cut a line or a
resistor... (Thats what it needs in the old TeacDrives.)
Bye
"Rolf Harrmann" <***@email.de> schrieb im Newsbeitrag news:***@4ax.com...
| Hello Jürgen,
|
| "Jürgen Strobel" schrieb:
|
| >i have a Teac FD-55GFR 7193 Floppy which is a 1,2MB Drive.
| >I have changed it to use 300RPM for 720KB 80 Tracks double sided; single
|
| Look this Link http://www.teac.com/DSPD/catalog.htm
|
| I hope these Link help You.
|
|
| Regards
| Rolf
|
| Form Germany
|
| Ask to the E-Mail ".News." remove.
|