[Coco] So, does anyone know where to get disk drives?

[Joel Ewy]

On 09/03/2013 06:28 PM, Christopher Smith wrote:
> Hey Joel,
>
> Now that I think of it, how would this work from RSDOS?  The drives would be operating at 300RPM, but unless the media selector were in the correct state, they would still think they had a high track count, right?  ... so that RSDOS would write tracks too close together to work with disks made on other CoCo drives?  I suppose one could do something either in hardware or software to hit the density selector and set it appropriately.  Do they also have a jumper for this?  Wiring a switch into that would be an easy solution.
>
> Chris

I do have some low density drives as well.  I wouldn't try using the 80 
track drives for DECB if you expect them to be compatible with other 40 
track drives.  However, I have used 1.44M 3.5" drives with 720K disks 
under DECB for years with patched BASIC ROMs so I can format the back 
side as well.  Obviously there's some wasted space, as BASIC only 
formats 35 tracks.  But an 80 track disk is great for OS-9.

JCE

>
> ----- Original Message -----
>> From: "Joel Ewy" <jcewy at swbell.net>
>> To: coco at maltedmedia.com
>> Sent: Sunday, September 1, 2013 9:10:50 PM
>> Subject: Re: [Coco] So, does anyone know where to get disk drives?
>>
>> On 08/29/2013 01:04 AM, Mike Pepe wrote:
>>> (most) 1.2MB PC drives are useless- they spin at a different rate.
>>>
>>> Aside from the complications of building the cable with the proper
>>> twist and
>>> connectors, the 3.5" works great. In a pinch you can use high
>>> density disks
>>> and cover up the HD hole, but I wouldn't trust it with anything I
>>> cared
>>> about.
>>>
>>>
>>> ...[snip]
>> I do have a number of Teac FD-55GFR drives, which are 1.2M 5.25"
>> drives
>> that can be jumpered for a 300 RPM spindle speed.  These could be
>> used
>> with DD media and formatted to 720K in OS-9.  In this case you don't
>> have the magnetic coercivity issue that you get with trying to format
>> HD
>> media to low density.  What I've read suggests that the only
>> difference
>> between the double density and quad density disks is that the QD
>> media
>> have been certified (tested) to work at a track density of 96tpi.
>>   Maybe
>> I'll experiment with this and see how well it works on a CoCo.
>>
>> JCE
>>
>>
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