[Coco] Re: [Color Computer] 1.44 disk

[Davey Brain]

Gene Heskett wrote:
> On Tuesday 02 August 2005 15:38, stacey wrote:
> 
>>can u use 1.44 diskettes in a 720k drive   will they work ok
>>
> 
> Generally speaking, no.  The media for the HD disks has a magnetic 
> coating thats harder magneticly, and requires more drive to make an 
> adequate recording.  It might work 5 minutes after you do it, but 2 
> weeks later all bets are off.
> 
> I've noticed that todays crop of aftermarket 3.5" floppies also seem 
> to have another problem.  Insert an HD diskette, and they demand a 
> 500 kilobaud data rate and will not function at all at the 250 
> kilobaud rate the coco controllers can muster.  Same drive with a DD 
> diskette in it works flawlessly at the coco's 250 kilobaud data rate.
> 

Hi,
I held off on this discussion but now I must jump in as we have been 
round & round this topic in the TI-99 groups and I can state with 100% 
confidence that there is absolutely no (zero, nada, zip) difference in 
the magnetic coercivity between 720k and 1.44m brand-name floppies; the 
only major difference is the number of holes in the plastic. On the 
TI-99 they can be used interchangably with 100% confidence & 
reliability. It is only the 5.25" disks where it makes a difference; the 
magnetic coercivity is different between DD (hub ring) & HD (no hub 
ring). Also, all 3.5" drives spin at the same speed whereas 5.25" DD 
drives spin at 300 rpm and HD drives spin at 360 rpm. In another (older) 
life I was an electronics technician with a repair shop and still have 
much info on electronic and computer hardware. So if you desire I can 
try to find my huge hardware/upgrade guides and quote the exact passages 
from those book as I have on the other groups.

If I understand you there are problems between the 720/1.44 drives/disks 
on the CoCo. This is most likely from some other cause (such as the 
difference in Kbaud rate as you suggested). On my TI-99/4a system (1.44m 
drive reading/writing 360k) and my Atari MegaST2 system (720k drive) I 
commonly have used both types of disks to carry files between it and my 
main PC with no problems, even 2 years later. But I MUST use 360k 5.25" 
drives/floppies on my TI-99 system as 1.2M simply don't work (side note: 
the uncommon QD 720k 5.25" drives DO work at 360k but only with DD/QD 
floppy disks just as on the 360k drives).

As usual YMMV and always back-up important files in more than one place.

WarpDavey
-- 
Davey Brain
Due to political oppression I'm seeking a Canadian or European 
spouse...any takers?

"It is dangerous to be right when the established authorities are wrong" 
- Voltaire

This OS/2 uptime is 7 d 11 h 37 m 27 seconds



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