25 Jun
2013
25 Jun
'13
6:55 a.m.
Stupid question, but here we go :o)
In Brazil, as you may imagine, 3.5 drives for apple computers are pretty
rare. But you can find with some effort internal macintosh drives from the
tras...eh...performa computers that nobody wants. I got my IIgs (with no
floppy drives) and made a simple pinout converter for using my old apple
clone drives
(http://www.tabajara-labs.blogspot.com.br/2013/06/e-quem-nao-tem-adaptador-d…).
But reading the schematic of IIgs, I **BELIEVE** I can use the 800K or
1.44MB internal drives from macs into the 19 pin port of the IIgs. After
all, is the same IWM the old macs use. I just have some questions which I
wasn't able to answer yet:
- How are 3.5 drives selected? I **believe** I must make an AND with
ENABLEx and 3.5_ENABLE lines
- Was it tested yet? I wasn't able to find anything concrete on the net
- Superdrives doesn't have the speed select pin?
- How is the disk ejected? I see no control for it on the drive pinout.
I believe a combination of the pins or some kind of signal change is needed,
but since I don't have an original apple drive, I'm not able to put the
logic analyser and discover how it works :o(
Thanks :)
Alexandre (full of nasty ideas :D)
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
25 Jun
25 Jun
8:01 a.m.
--- On Tue, 6/25/13, Alexandre Souza <alexandre.tabajara at gmail.com> wrote:
I **BELIEVE** I can use
the 800K or 1.44MB internal drives from macs into the 19 pin
port of the IIgs. After all, is the same IWM the old macs
use.
Yes. You can. You can use any of the auto inject drives from a Macintosh, connected to
that 19 pin port on the back. The 800k mechanism in the external 3.5" drive is
exactly the same as the one in a Mac. And you can swap the mechanism in an external drive
with a Superdrive and it will work with the IIgs as 800K, it just won't work as a
Superdrive unless you have the (very rare) Superdrive controller for the IIgs.
The eject button on the external drive is connected to the little board in the external
drive enclosure with the daisy chain connector on it. I don't remember the specifics
of that board off the top of my head, unfortunately.
I forget exactly how drive select is done on the 3.5 drives, but I know on the Unidisk
5.25, there are two pins for drive select. 9 and 17, IIRC. 17 selects the first drive, 9
selects the second, and 9 on the first drive is routed to 17 on the daisy chain connector
for the second. I think there's an additional pin for 3.5 enable. Hence why you have
to have the 3.5" drives first in the chain, before the 5.25's.
-Ian
8:55 a.m.
On 6/25/13 8:01 AM, Mr Ian Primus wrote:
--- On Tue, 6/25/13, Alexandre Souza
<alexandre.tabajara at gmail.com> wrote:
I uploaded a document to http://bitsavers.org/pdf/apple/disk/sony/ that describes
the differences in pinout.
I **BELIEVE** I can use
the 800K or 1.44MB internal drives from macs into the 19 pin
port of the IIgs. After all, is the same IWM the old macs
use.
Yes. You can. You can use any of the auto inject drives from a Macintosh, connected to
that 19 pin port on the back. The 800k mechanism in the external 3.5" drive is
exactly the same as the one in a Mac. And you can swap the mechanism in an external drive
with a Superdrive and it will work with the IIgs as 800K, it just won't work as a
Superdrive unless you have the (very rare) Superdrive controller for the IIgs.
The eject button on the external drive is connected to the little board in the external
drive enclosure with the daisy chain connector on it. I don't remember the specifics
of that board off the top of my head, unfortunately.
I forget exactly how drive select is done on the 3.5 drives, but I know on the Unidisk
5.25, there are two pins for drive select. 9 and 17, IIRC. 17 selects the first drive, 9
selects the second, and 9 on the first drive is routed to 17 on the daisy chain connector
for the second. I think there's an additional pin for 3.5 enable. Hence why you have
to have the 3.5" drives first in the chain, before the 5.25's.
-Ian
9:21 a.m.
I uploaded a document to
http://bitsavers.org/pdf/apple/disk/sony/ that
describes the differences in pinout.
Thanks a lot, Al! The Unidisk doc tells me one of the most important
things I needed to know - the disk eject is controlled by the pin 20 of the
interface. It wasn't written anywhere!!!
I'll do some tests later today :)
12:42 p.m.
On Tue, Jun 25, 2013 at 11:55 AM, Al Kossow <aek at bitsavers.org> wrote:
On 6/25/13 8:01 AM, Mr Ian Primus wrote:
Thanks for this, Al. I was looking at the multicolumn table "pin assignment
on Apple floppy disk drive" to see some of what I was looking for when I
recently asked about using a double-sided floppy on an original 128K
Mac with original (MFS-only) 64K ROMs. I see the following differences
between "single sided Mac" and "double sided Mac" which must be
part of the whole "red stripe"/"yellow stripe" floppy cable thing...
DB-19 pin 9 / 20-pin-cable pin 17
/ENABL2 in other drives/machines
Mac single-sided and double-sided: "+12V in drive / No Wire"
DB-19 pin 5 / 20-pin-cable pin 9
-12V in most cases in other drives/machines
"no wire" on Mac drives (-12V on host)
DB-19 pin 10 / 20-pin-cable pin 19 or 20
WRPROT in most cases in other drives/machines
Mac single-sided: PWM (on 20)
Mac double-sided: "N.C. in drive/PWM in Mac" (on 20)
So... it looks like a wire or two differences in the power, the
functional difference between single-sided and double-sided is the PWM
line on pin 20 on a single-sided drive is a No Connect on a
double-sided drive. I do remember that the 400K (single-sided) drives
changed pitch as they ran the heads in and out, obviously controlled
by the PWM line from the Mac, and that the 800K (double-sided) drives
did not change pitch.
My goal is to put together a 128K Mac with an internal and an external
floppy drive for exhibit/display purposes (mostly to show what a PITA
it was to use the original, unexpanded Mac). I have a fully-working
Mac with keyboard and mouse and functional internal floppy. The thing
I'm trying to do is add a single external floppy for outboard data and
applications to minimize the "floppy dance" (and I think historically
it was somewhat common to bite the bullet and pay for a second floppy
drive when hard drives were unavailable or nearly as expensive as the
machine itself). I know they quickly dumped the 128K Mac in favor of
512K of RAM (and equally as quickly standardized on 1MB with the dawn
of the Mac Plus), but the point of the exercise is being
semi-productive with 128K and no hard disk.
This being an entirely optional exercise, I'm not likely to scour eBay
for an old M130 drive. I do have the shell of an M130 from a drive
that died 25 years ago, so I'm willing to entertain hiding a
double-sided drive mech inside the "correct" enclosure. If a newer
drive mech will sufficiently act like an older one (doing the right
thing with linear bit density as the heads step in and out, and not
caring that only one head is ever selected), then I might be able to
pull this off. Alternately, I don't mind picking up an inexpensive
working M130 (even if it needs cleaned/lubed) but they aren't as
common as they once were.
I guess as long as I don't route +12V or -12V where it's not welcome,
the other differences aren't likely to break anything, but if anyone
has any advice or suggestions on mixing and matching drives and the
most ancient of Macs, I'm willing to listen and save any time and
frustration trying things that are known not to work.
-ethan
I forget exactly how drive select is done on the
3.5 drives, but I know on
the Unidisk 5.25, there are two pins for drive select. 9 and 17...
I uploaded a document to http://bitsavers.org/pdf/apple/disk/sony/ that
describes the differences in pinout.
1:02 p.m.
http://www.vintagemacworld.com/drives.html
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
----- Original Message -----
From: "Ethan Dicks" <ethan.dicks at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Tuesday, June 25, 2013 4:42 PM
Subject: Re: Using an internal Superdrive or 800K macintosh floppy on IIgs
On Tue, Jun 25, 2013 at 11:55 AM, Al Kossow <aek at
bitsavers.org> wrote:
On 6/25/13 8:01 AM, Mr Ian Primus wrote:
Thanks for this, Al. I was looking at the multicolumn table "pin
assignment
on Apple floppy disk drive" to see some of what I was looking for when I
recently asked about using a double-sided floppy on an original 128K
Mac with original (MFS-only) 64K ROMs. I see the following differences
between "single sided Mac" and "double sided Mac" which must be
part of the whole "red stripe"/"yellow stripe" floppy cable thing...
DB-19 pin 9 / 20-pin-cable pin 17
/ENABL2 in other drives/machines
Mac single-sided and double-sided: "+12V in drive / No Wire"
DB-19 pin 5 / 20-pin-cable pin 9
-12V in most cases in other drives/machines
"no wire" on Mac drives (-12V on host)
DB-19 pin 10 / 20-pin-cable pin 19 or 20
WRPROT in most cases in other drives/machines
Mac single-sided: PWM (on 20)
Mac double-sided: "N.C. in drive/PWM in Mac" (on 20)
So... it looks like a wire or two differences in the power, the
functional difference between single-sided and double-sided is the PWM
line on pin 20 on a single-sided drive is a No Connect on a
double-sided drive. I do remember that the 400K (single-sided) drives
changed pitch as they ran the heads in and out, obviously controlled
by the PWM line from the Mac, and that the 800K (double-sided) drives
did not change pitch.
My goal is to put together a 128K Mac with an internal and an external
floppy drive for exhibit/display purposes (mostly to show what a PITA
it was to use the original, unexpanded Mac). I have a fully-working
Mac with keyboard and mouse and functional internal floppy. The thing
I'm trying to do is add a single external floppy for outboard data and
applications to minimize the "floppy dance" (and I think historically
it was somewhat common to bite the bullet and pay for a second floppy
drive when hard drives were unavailable or nearly as expensive as the
machine itself). I know they quickly dumped the 128K Mac in favor of
512K of RAM (and equally as quickly standardized on 1MB with the dawn
of the Mac Plus), but the point of the exercise is being
semi-productive with 128K and no hard disk.
This being an entirely optional exercise, I'm not likely to scour eBay
for an old M130 drive. I do have the shell of an M130 from a drive
that died 25 years ago, so I'm willing to entertain hiding a
double-sided drive mech inside the "correct" enclosure. If a newer
drive mech will sufficiently act like an older one (doing the right
thing with linear bit density as the heads step in and out, and not
caring that only one head is ever selected), then I might be able to
pull this off. Alternately, I don't mind picking up an inexpensive
working M130 (even if it needs cleaned/lubed) but they aren't as
common as they once were.
I guess as long as I don't route +12V or -12V where it's not welcome,
the other differences aren't likely to break anything, but if anyone
has any advice or suggestions on mixing and matching drives and the
most ancient of Macs, I'm willing to listen and save any time and
frustration trying things that are known not to work.
-ethan I forget exactly how drive select is done on the
3.5 drives, but I know
on
the Unidisk 5.25, there are two pins for drive select. 9 and 17...
I uploaded a document to http://bitsavers.org/pdf/apple/disk/sony/ that
describes the differences in pinout.
1:17 p.m.
On Tue, Jun 25, 2013 at 4:02 PM, Alexandre Souza
<alexandre.tabajara at gmail.com> wrote:
Yes. that page came up in my earlier thread. I have an empty M0130
box (no drive, no mounting brackets, no cables...) and a couple of M0131
drives, but there's apparently insufficient memory on a 128K Mac to use
the HD20 INIT (it works fine on a 512K Mac).
What I guess I should try is this...
http://68kmla.org/forums/viewtopic.php?f=29&t=17418
... attach my M0131 to the Mac 128K and just have to format
single-sided 400K MFS disks in the internal drive but use them as
400K disks in the external M0131. I could also see about migrating
the guts of the M0131 into my M0130 shell for the exhibit for
appearance's sake.
Fortunately I still have a pile of "720K" media from my Amiga
days (where we formatted them to 880K" - 11 512-byte sectors
per track, double-sided).
-ethan
10:04 p.m.
Good news, bad news.
Good news I got a nice understanding of the inner works of the Macintosh
drive :o) Nice toy :o)
Bad news: It will NEVER EVER EVER work on IIgs without a microcontroller
on the bus. The smartsbrubbles bus is WAY MORE COMPLICATED than I though. I
got the correct docs for the drive interface implementation and it is a
nightmare of back and forth commands.
As a friend said, "it is cheaper to buy a $20 drive". I do agree.
I'm studying the bus and I'll try to program a microcontroller for doing
this task, but just for the fun of it :op
Thanks all :o)
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
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ian_primus＠yahoo.com