Re: Hardware musings

[Mark McDougall <markm@vl.com.au>]

Michael J. Mahon wrote:

> Ed Eastman wrote:

>> Recreation of some original disks in it's original analog format is
>> impossible without specific special hardware.  So recreation becomes
>> irrelevant so long as the data was captured and the disk image is
>> usable in an emulator.  Maybe later hacking could reproduce a copy
>> that works, but that's not what you want.
> 
> I'm not convinced of that.  That assumes that some disks were written
> on non-standard disk duplicating machines, which seems unlikely, and
> that the effect of such writing is discernable by an Apple drive.
	(snip)
> With that exception, I think that an Apple drive, of appropriate
> (perhaps non-standard) speed, is capable of writing any disk that
> an Apple program is capable of detecting.

I'm not familiar with Apple II protection schemes, but I do recall some
early PC protection schemes involved the creation of a floppy with some
sort of hard error that could *NOT* be duplicated on a standard end-user
floppy disk drive. I can't recall the exact details, but it may have
involved physically altering the media surface in a specific place/manner?!?

I guess this information could be captured in an 'analogue copy' of the
original disk, and you could enable emulators to run it, but there'd be
no way to duplicate such a disk on a real, physical floppy disk using
standard drives.

Regards,

-- 
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266