[Coco] Disk drive questions?

[Ray Watts]

ostro011 wrote:

>On 3 Dec 2003, Ray Watts wrote:
>  
>
>>Gene Heskett wrote:
>>
>>    
>>
>>>       
>>>
>>>>>>                   
>>>>>>
>>>>>Does this easy setup work through BASIC as well as OS9,
>>>>>or is your system
>>>>>OS9 only.  If a person has a set of two double-sided
>>>>>5.25" drives now, can
>>>>>one set be replaced with 3.5" drives and still work in
>>>>>BASIC?
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>>I should have clarified that I am running with Basic and
>>>>not OS-9.   Is this an issue?
>>>>
>>>>Jim
>>>>   
>>>>
>>>>        
>>>>
>>>It can be, because the disk format is carved in the eprom data, 
>>>whereas with os9 the descriptor can be played with, gaining access to 
>>>the other side of the disk etc.
>>>
>>> 
>>>
>>>      
>>>
>>Gene,   Either I didn't understand the question, or I don't understand 
>>your reply.  DS/DD 5.25" drives and DS/DD 3.5" drives look identical to 
>>the CoCo and can be mixed and matched.  Under the DECB ROM, they will 
>>all look exactly the same and, under OS9, they will become whatever 
>>descriptor you give each one - in a range of 160k to 720k.  Am I looking 
>>at something cross-eyed?   
>>
>>    
>>
>
>Ray, thanks for being so patient.  I am a "software" oriented guy but a
>hardware imbicile.  (Mark Marlett has had to come to my rescue multiple
>times for hardware issues.)  I guess what is driving this exchange, at
>least for me, is the desire to move data between a Coco and a PC.  Most new
>PCs now do not have 5.25" drives and I don't think they support that
>format, and most standard Coco systems only have 5.25" drives.  Putting a
>3.5" drive on a Coco would help bridge this gap.
>
>I think you are saying that without any special software, I can unplug one
>of my 5.25" drives on the Coco and replug in a 3.5" drive (720K or 1.4M ?)
>and still be able to store the same information from either OS9 or BASIC. 
>The Coco doesn't care.  I can BACKUP 0 TO 1 if I want and the Coco will
>make the copy.
>
>Assuming this is correct, I now have Coco data on a 3.5" diskette which
>should be able to be ported into a modern PC using its 3.5" HD drive.
>
>-- Steve --
>
>
>
>  
>
Steve,   Now you are throwing a little crap into the game.  My original 
reply to Jim Cox was in regards to operating with a CoCo.  No mention 
was made of transferring data to a PC.  That raises all sorts of  file 
conversion problems and what the PC will accept for a drive.  Also, you 
cannot use a HD (1.4mb) drive with a CoCo without some heavy hardware 
hacking.  The only way it will work is if it is a dual mode drive that 
senses 720k disks. I think most of them are of this type.  It does this 
by looking for a "write-protect" type of hole, which exists opposite the 
write protect hole.  1.4 mb disks have a hole there, 720 kb disks do 
not.  The drive will then change it's mode accordingly.  BTW - if you 
have such a drive, and only have 1.4 mb disks, you can apply a write 
protect sticker over the senser hole and use it for 720 kb.  PC 
transfers on my Mac are done with 720 kb disks, written in PCDOS format, 
on an Imation Superdisk unit.
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