Re: annc: GS/OS AppleDisk5.25 Project

["Charlie" <charlieDOTd@verEYEzon.net>]

"Steven Hirsch" <snhirsch@gmail.com> wrote in message 
1p6dnXqfLPZZdhXUnZ2dnUVZ_jOdnZ2d@giganews.com">news:1p6dnXqfLPZZdhXUnZ2dnUVZ_jOdnZ2d@giganews.com...
> Charlie wrote:
>> "Steven Hirsch" <snhirsch@gmail.com> wrote in message 
>> YdKdnWEBU6Dx5RXUnZ2dnUVZ_h2WnZ2d@giganews.com">news:YdKdnWEBU6Dx5RXUnZ2dnUVZ_h2WnZ2d@giganews.com...
>>> Alex Freed wrote:
>>>> sicklittlemonkey wrote:
>>>>> Are you talking about reading actual Apple II disks, a la FDI etc, or
>>>>> just reading and writing to modern HD media via an emulation of 5.25 &
>>>>> 3.5 GCR formats?
>>>> After posting I remembered that the Apple 3.5" disks were "special".
>>>> AFAIK they use variable speed to using a PC drive to read/write Apple
>>>> 3.5" disks is at least difficult.
>>> Wouldn't it be possible to cleverly emulate the variable speed zones in 
>>> software by playing with the data rate?  (For some value of cleverness 
>>> at any rate).
>>>
>>> Steve
>>
>> Yes, Disk2FDI manages to read Apple 3.5" disks in PC type (single speed) 
>> 3.5" drives.
>
> I didn't realize that disk2fdi worked with 3.5" drives!

It also supports 3" drives (whatever they are) and 8" drives.  I've found 
when reading 3.5" Apple II disks there is an occasional disk that won't read 
in either the upper tracks or the lower tracks.  Using a different 3.5" PC 
drive usually cures the problem.

> Another example is the Copy II Plus option board.  Unless I'm confusing it 
> with something else, it was able to read and duplicate 800K Mac diskettes 
> (same low-level format, I think).

I'm not familiar with the Copy II Plus board but another interesting card is 
the PC Transporter.  It can read/write an Apple II 3.5" drive in either GCR 
with the variable speed (800K) or PC MFM with single speed (720K).  In this 
case though, I don't believe the speed is done in software.  If I remember 
correctly the PC Transporter somehow keeps the speed from varying in the 
drive.

Charlie