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Attaching an 8" floppy drive to DN3/4XXX machine

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Kurt Nowak

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Apr 5, 2012, 12:52:24 PM4/5/12
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Hey Guys...

So I have a bunch of 8" floppies that I would like to get the data Apollo off of. The problem is that my only 8" drive is attached to a dead DN420. Would a "newer" say DN3500 accept this floppy drive (temporarily) so I can get the data? I can use either a machine running SR10 or SR9.7.5...

-Kurt

Jim Rees

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Apr 6, 2012, 11:04:00 PM4/6/12
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On Apr 5, 12:52 pm, Kurt Nowak <kurt.m.no...@gmail.com> wrote:
> Hey Guys...
>
> So I have a bunch of 8" floppies that I would like to get the data Apollo off of. The problem is that my only 8" drive is attached to a dead DN420. Would a "newer" say DN3500 accept this floppy drive (temporarily) so I can get the data? I can use either a machine running SR10 or SR9.7.5...

Not without a whole lot of work. The floppy controller in the dn3500
has a 34 pin sa450 connector for a 3 or 5 inch drive. The 8 inch drive
has a 50 pin sa850 connector. The timing is the same, they both spin
at the same speed, and some of the signals are the same, but there are
some extra signals on the 8 inch.

I once did the opposite of this, attached a 5 inch drive to a dn330.
It was not easy. And what you're trying to do will be harder. But I
can send you my notes if you want to give it a shot.

Another approach would be to find some other non-Apollo system (CP/M?)
that already has an 8 inch floppy drive, convince it to read the 1K
Apollo sectors, image the floppies, then read them on the emulator.

supervinx

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Apr 7, 2012, 4:02:07 AM4/7/12
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> Not without a whole lot of work. The floppy controller in the dn3500 has
> a 34 pin sa450 connector for a 3 or 5 inch drive. The 8 inch drive has a
> 50 pin sa850 connector. The timing is the same, they both spin at the
> same speed, and some of the signals are the same, but there are some
> extra signals on the 8 inch.
>

So I could use a 1440 KB floppy drive instead of the 1200 KB ?
I've plenty of both, it's not an issue, it's a curiosity ...

http://www.supervinx.com/Retrocomputer

Jim Rees

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Apr 7, 2012, 7:34:02 PM4/7/12
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On Apr 7, 4:02 am, supervinx <ness...@libero.it> wrote:
> So I could use a 1440 KB floppy drive instead of the 1200 KB ?
> I've plenty of both, it's not an issue, it's a curiosity ...

Not sure what you mean. The 8 inch floppy only has 77 tracks, the 3
and 5 have 80. If you adapt your 8 inch drive to the dn3000, you'll
have to tell invol the capacity is 1.2 rather than 1.4. But I think if
you just want to read your old 8 inch floppies it should work fine
since the disk size is given in the lvol header.

supervinx

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Apr 7, 2012, 8:08:59 PM4/7/12
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You stated
> The floppy controller in the dn3500 has
> a 34 pin sa450 connector for a 3 or 5 inch drive.
>
I've always connected a 1200K drive, never thought to connect a 3.5" drive.
It's possible ?


--
http://www.supervinx.com/Retrocomputer

Jim Rees

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Apr 8, 2012, 8:54:00 AM4/8/12
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Yes, the 3 and 5 inch drives have the same interface, although the
connector is different. It should be easy to find an adaptor. I don't
think the computer can even tell the difference between the two drives.

Lothar Paltins

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Apr 8, 2012, 5:21:10 PM4/8/12
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Jim Rees wrote:

> Yes, the 3 and 5 inch drives have the same interface, although the
> connector is different. It should be easy to find an adaptor. I don't
> think the computer can even tell the difference between the two drives.

There's one exception, the spindle speed. A HD 5 1/4" floppy rotates at
360 rpm and a 3 1/2" floppy at 300 rpm. It will be necessary to switch
the controller to 300 rpm. I think, for the WD7000 controller this can
be done by removing the jumper W3 (Floppy Spindle Speed). I don't know,
whether the Precompensation jumper W2 should also be removed. The
"Floppy Control" jumpers W1 and W4 should probably be left unchanged.
Unfortunately, there's no description of the individual jumpers of the
Omti controllers in the "Domain Personal Workstations and Servers
Technical Reference" manual.

--
Lothar Paltins lpt...@arcor.de

Kurt Nowak

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Apr 9, 2012, 3:04:38 PM4/9/12
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Thanks, Jim. That does sound like more work than I was willing to put in. I just wanted to test the waters and see if one of you knew what I was getting myself into before I start pulling hardware out of machines...
I was planning on giving my DN420 away (hopefully for a little cash) to Bear at typewritten...Perhaps he can get the machine to work and at that point maybe he can extract the data off the floppies for me. We'll see...not a big rush on this one.
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