[Coco] Read Coco floppies in my PC

[Aaron Wolfe]

http://www.oldskool.org/guides/oldonnew/hardware/1.2mb_to_360k.html
"Everybody knows that trying to write to a 360K disk in a 1.2MB drive
usually works fine for the 1.2 MB drive, but then renders the disk
mostly unusable for the 360K drive. "

http://www.brutman.com/PCjr/diskette_handling.html
"A high density 5.25" drive can read a low density diskette just fine,
even though the drive head is narrow compared to the track.  However,
if you try to write to the diskette, you will write a new track of
data that is much narrower than the existing data.  This will
generally make the diskette unreadable in a double density drive.."

http://www.vintage-computer.com/vcforum/archive/index.php/t-12114.html
"You should ALWAYS format the disk in the 360kB drive. Most of the
time writing data in a 1.2MB drive leaves it unreadable in the 360kB
one"

http://www.retrotechnology.com/herbs_stuff/drive.html#12meg
"..ever since the first high-density 1.2Mb drives and media were
introduced for the IBM PC. People compain they can't read 360K
diskettes formatted or written on a 1.2M drive.."

http://books.google.com/books?id=kG8LcWfruOAC&pg=PT145&lpg=PT145
"..once that diskette has been written or formatted in the 1.2 MB
drive, it will no longer be reliably readable in a 360 KB drive."

http://www.linux-tutorial.info/modules.php?name=MContent&pageid=128
"Problems arise if you use a disk formatted at 360K in a 1.2Mb drive."

etc..




On Sat, Mar 31, 2012 at 12:11 AM, Chad H <chadbh74 at hotmail.com> wrote:
> Sorry..nothing against you...but I've spent most of my adult life doing things microsoft said couldn't be done.
>
> I think in all fairness, whether one has problems or not with this 360k issue depends on what combination of OS + Drive model they are using to work with thr 360k media..  I've used win98 almost exclusively with good TEAC and Fujitsu drives
>
> Aaron Wolfe <aawolfe at gmail.com> wrote:
>
>>Your results are atypical.
>>
>>The problems between 1.2mb drives and 360k drives are very well known.
>> This used to be common knowledge, but I guess its been a good long
>>time since anything regarding floppy disks was well known.
>>
>>For instance, this microsoft article details the problem:
>>
>>http://support.microsoft.com/kb/79538
>>
>>You will find further documentation in the wikipedia article on floppy disks:
>>
>>http://en.wikipedia.org/wiki/Floppy_disk#5+1.E2.81.844-inch_floppy_disk
>>
>>The crux of the issue is that 1.2MB FDD use a narrower track than 360k
>>disks by design.  The read head on a 1.2MB FDD can easily read the
>>wide tracks written by a 360k drive, and it can also read the narrower
>>tracks written by 1.2MB drives.  However, 360k drives cannot usually
>>read the narrow tracks written by a 1.2MB drive.  This means writing
>>to a 360k disk with a 1.2MB drive generally renders the disk
>>unreadable by 360k drives.  This is a physical property of the write
>>head and not something changeable via software.
>>
>>
>>..
>>
>>On Fri, Mar 30, 2012 at 11:53 PM, Chad H <chadbh74 at hotmail.com> wrote:
>>> I have 9 360k pc-xt drives, all fully tested to read/write disks formatted by 1.2 mb drives without problems....?????
>>>
>>> Michael Graham <mkgraham at gmx.com> wrote:
>>>
>>>>Just FYI, most double-density (360k) drives won't read double-density
>>>>disks written on high-density (1.2M) drives.  I tried this when I first
>>>>got my PCjr, and it didn't work, so I had to swap the 360k drive back
>>>>and forth between my PCjr and my old desktop machine until I could
>>>>source another 360k drive.  I couldn't get disks written in a 1.2M drive
>>>>to read on my CoCo, either.  However, disks written with a 360k drive
>>>>will read back just fine on a 1.2M drive, as long as you don't try to
>>>>write to them.
>>>>
>>>>On 3/30/2012 8:20 PM, Bill wrote:
>>>>> The drives I just got are 1.2Mb, and I have tried several times to format a
>>>>> 360K disk, but for some reason it won't let me. I type in the command format
>>>>> b: /f:360 (which SHOULD work), but it gives me an error message.
>>>>>
>>>>> Has ANYONE been successful formatting a 360K disk in XP with a  1.2Mb drive?
>>>>>
>>>>> Thanks
>>>>>
>>>>>
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>>>>
>>>>
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>>>>
>>>
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>>
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