[Coco] Issues with 26-3022 interface

Juan Castro jccyc1965 at gmail.com
Tue Feb 12 21:12:12 EST 2013


Your floppies have been formatted with 256 byte sectors. Each track has 18
sectors of 256 bytes instead of 9 sectors of 512 bytes like in a 720KB PC
disk. You'll need to (a) get a PC with a FDC old enough to read that, and
(b) get some DOS software that can program the FDC and read/write a 256
byte formatted disk. That will be a challenge. Anyone here has successfully
done that?

On Tue, Feb 12, 2013 at 1:26 PM, Daniel Campos <daniel.campus at gmail.com>wrote:

> Hi Mark,
>
> I understand your point, as this subject have probably been talked on this
> list many times over. But my main purpose is to pass disk images from a PC
> (through emulator or some other program) and run them on the Coco. I don't
> have any legacy 5 1/4 disks to worry about, so if I can do this work on a 3
> 1/2 floppy, for me is the best choice.
>
> I will try now to transfer some images from the PC to this disks and let's
> see how will it work...
>
> Thanks!
> Daniel
>
> Em 12/02/2013 13:04, Mark Marlette escreveu:
>
>  Daniel,
>>
>> Understand the beast in which you are trying to tame.......... :)
>>
>> Go read what occurs and the differences between all of the disk formats
>> and densities on a hardware and software level.
>>
>> You will then realize as it 'might' appear to have worked, you are in
>> violation of the specs.
>>
>> This has been beat to death here. Follow the specs and it will always
>> work.  You are flirting with diasater if you assume it is working, IMHO.
>>
>> Regards,
>>
>> Mark
>>
>> http://www.cloud9tech.com
>>
>>
>>
>> ______________________________**__
>>   From: Daniel Campos <daniel.campus at gmail.com>
>> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
>> Sent: Tuesday, February 12, 2013 8:50 AM
>> Subject: Re: [Coco] Issues with 26-3022 interface
>>   Mark,
>>
>> Em 12/02/2013 11:56, Mark Marlette escreveu:
>>
>>> Daniel,
>>>
>>> This HD mod was created by Robert Brose of our computer club many years
>>> ago.
>>>
>>> I have done this mod, it works. I also added a line from the controller
>>> to the drive to automatically switch the transfer rate clock based upon the
>>> sensors in the drive rather than just the descriptor.
>>>
>>> With that said...this is NO easy mod. Almost easier making a new
>>> controller.
>>>
>> Yes, for what I saw from the document that Harry sent, it will be no
>> easy task.
>>
>>  It requires a the MB8877A(??) memory loss ATM upgrade and then there was
>>> also a speed issue running at 1.78MHZ as well. A chip that needed
>>> replacing. Was pinged this past weekend on this at Cloud-9 and haven't had
>>> the chance to look up my work in my project documentation book. I have it.
>>>
>>> The file was up on RTSI for a long time. ????
>>>
>>> Regards,
>>>
>>> Mark
>>> http://www.cloud9tech.com
>>>
>>>
>>>
>>>  Ou of curiosity, I just attached today a 3 1/2 1.44M drive to the Coco
>> and it worked flawlessly! It formated the disk (a HD disk with the role
>> closed to make the drive understand it as 720Kb disk) and SAVEd and
>> LOADed some programs. No errors ocurred during the format process!
>> How can I check the disk to see if it was formated properly ?
>>
>> This drive is a Mitsumi D359M3D and was already configured to DS0,
>> because I used it before with one of my MSX machines.
>>
>> Thanks!
>>
>> Daniel
>>
>>
>>
>>
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>
>
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