Re: Reading apple disks on PC

["Charlie" <charlied@NOSPAMbboard.com>]

"Michael Pender" <mpender@hotmail.com> wrote in message
news:XAFQa.1178$OC4.956@nwrddc01.gnilink.net...
> Paul Schlyter <pausch@saaf.se> wrote in message
> news:betttj$1b9n$1@merope.saaf.se...
> > In article <yLtQa.13001$D%1.10374@nwrddc01.gnilink.net>,
> > Michael Pender <mpender@hotmail.com> wrote:
> >
> > The incompatibility in disk format which makes it impossible to read
> > Apple disks in standard PC hardware is at the lowest-level encoding:
> > the Apple II used GCR whihe the PC uses MFM.  Early Macs used GCR
> > too; later MFM disks were used by Mac but a lot of Macs have floppy
> > drives capable of reading GCR disks too.  PC floppy drives have
> > never been able to read GCR disks and will never be.
>
> Is a reference available that outlines the differences between GCR and MFM?
> If that is the only difference, then it should be possible to read/write
> PC-format disks on an Apple II, even if the opposite is not true.
>

An Apple 3.5" (800K) drive is capable of reading/writing PC-format disks (720K)
but the Apple controller is not.  I use an Applied Engineering PC Transporter
card with an Apple 3.5" drive attached to it.  It works perfectly with 720K
MS-DOS disks as long as they are formatted on a real PC.  When using the Apple
3.5" drive for ProDOS the speed is slower than if it was attached to the Apple
(SmartPort) controller.

It is my understanding that Apple 5.25" drives cannot read/write MFM at all.

Charlie