[Coco] Warning about 3.5" disk failure

[Bob Devries]

Mike,

Thanks for that comment.

I was however, referring not only to Coco disks, but also to other 
computers. In fact, the computer I first noticed it on was my MM/1. I have 
yet to determine if what you said applies to the controller chip used in 
that computer, and indeed in PC clones. The Amiga may or may not have that 
problem also; not sure.

--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- 
From: "Mike Pepe" <lamune at doki-doki.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, March 13, 2007 12:45 AM
Subject: Re: [Coco] Warning about 3.5" disk failure


> Bob,
>
>> Since both the PC and the Coco use the index as the sync for a start of 
>> track, and the index is produced in the mechanism of the drive, altering 
>> the relationship between the drive and the disk, means that the disk 
>> becomes unreadable.
>
> As I recall, I've covered the index hole on floppies lots of times. It 
> does not affect reading or writing. Our drives our soft-sectored, the 
> start of the track is determined by reading the track's data, and the 
> index pulse has nothing to do with the actual reading and writing of the 
> data.
>
> It does affect formatting. You absolutely cannot format a disk unless the 
> index is present.
>
> Give it a shot, try some opaque tape over the index hole on a 5.25 incher 
> and see if the disk can be read. If not, my brain is faulty and it must be 
> something else I'm thinking of.
>
> -Mike
>
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