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8" floppy drive on a CoCo2: has anyone ever done it?

B

braids

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Nov 12, 2010
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Hi All,

I have ordered a Shugart SA801 and plan to connect it to a CoCo2 via a rebuilt and modded (TG43 signal!) controller with WD1773 to create capability for formatting (partially) bulk erased disks.

Can a CoCo, switched to 1.78mhz, generate enough data rate to feed the WD1773 trackwise to make a clean format on the disk?

Does anyone worked with 8" drives on 6809 color computers?
 
Better question is "Can one successfully clock a WD1773-02 at 16 MHz for an 8" drive?" It will probably run pretty hot. (Recall than 8" drive datarates are twice that of 5.25")
But let's assume that you can do it. Can the 1.78MHz CoCo handle the data rate from an 8" MFM disk--I suspect not, the speed isn't there. How about an FM disk--I haven't run the instruction timings, but I'll go out on a limb and say maybe.

Just spitballing here.
 
The CoCo’s controller handles 5.25” double density at the default .9mhz, so I would think single density 8” would be fine.

Running the CoCo’s prior to the CoCo3 at their double-clock speed involves some if-ands-buts, of course. My vague recollection is video refresh goes to heck if you access RAM at the high speed, the default fast poke only accessed ROM faster?
 
I've seen it done in person with a CoCo 1 and a TRS-80 external 8" drive, with the first gen controller pack. It does work! Question is was it a modded pack, sadly I dont know. He passed away years ago, so can't exactly ask him how he did it.

Still upsets me they tossed all his vintage gear away into a dumpster thinking it was worthless, and knowing i used to come over and help him with projects... His 2nd wife was really something else.
 
Well, are there any reports about handling 1.44M 3.5" HD media on a CoCo2 using stock HD floppy drives? If so, then an 8" MFM disk should be no problem.
 
Far as I understand it, you can use 1.44 drives on certain packs, but are limited to the amount of tracks it can use, which I believe 40? is max?
 
So you can use HD media and rotation speed, but the packs can only write 40 tracks max on the media. Now with a few aftermarket packs (Like my J&M pack), or patched 2nd/3rd gen RSDOS pack, you can have 80 tracks max. When it comes to OS/9 i'm not exactly sure as I dont have any experience with it.

There was also a weird Amdek pack, but never seen one in person.
 
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