[Coco] Read Coco floppies in my PC

Sat Mar 31 16:40:04 EDT 2012

Maybe I was just lucky? Then again it's been far to long ago for me to care.

I do remember it was a big issue at the time and the reason I had both sizes
in my machine. When writing a 360K floppy for someone else i would use the right
sized drive.

The Other Frank

On Sat, Mar 31, 2012 at 12:31:01AM -0400, Aaron Wolfe wrote:
> 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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