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Re: Hardware musings
Ed Eastman wrote:
Michael J. Mahon wrote:
But I thought part of the problem was making it possible for a user
with protected disks, but inexperienced in deprotection, to be able
to image their disks with some assurance that everything needed to be
able to run them under emulation, or duplicate them, has been captured.
But they can. Just copy everything... Once preserved, someone could
analyse the disk image and recreate the original to deprotect it or just
to make a new disk. (Good luck _writing_ every quarter track and have
the thing usable when through.)
Exactly--that's been my position, too. Why are we arguing? ;-)
I'd be worried about discarding information from the image file that
later (maybe *much* later) turned out to be needed. (Say, after you
reach the treasure chest and drop the bronze key... ;-)
I'd like a method that works for *everyone*, with or without an
Apple II (if they use the OP's notion of a microcontroller-controlled
drive connected via USB for the capture).
Even without an Apple II... Wow, that's ambitious. I just don't see
that happening unless someone comes up with a diskette reading mechanism
that does proper CGR.
We were origninally talking about a Disk ][ drive connected to a micro
connected via USB to a PC.
But I agree, my machine of choice for capturing images would be an
Apple II.
But ONLY the spiral images would contain that much information. Most
disk images will not.
So, you're willing to let a little matter of 4x storage space stand
in the way of capturing images of disks that you may never see?
Never. But why store so many tracks of data if you aren't going to need
them. Most (read 99.999%) of A2 disks would capture perfectly sticking
to the 80 (72) tracks the standard disk drive is capable of doing
without trickery. If for no other reason than the width of the head
precludes missing quarter track info. It's the synch that's a bear.
Sure, but how can an inexperienced user *be certain* that they are not
dealing with that small bunch of disks that require quarter track info?
Better safe than sorry.
Put another way, if, this late in the game, we are contemplating a
*new* disk image format, then there had better not be *any* disk that
it can't represent!
Let's see--10,000 protected disks, at about a megabyte apiece for a
completely uncompressed (unlikely) representation of *everything*,
adds up to 10GB--two DVDs or a tiny sliver of a recent hard disk!
Why should anyone worry about a 1MB image size today?
No one would.
The .pdf of the documentation and game materials may be bigger! ;-)
And usually WAY bigger. :)
Agreed.
Actually, you can't guarantee rotational uniformity to anywhere near
the length of a bit on a track, so if data was written with a non-
standard-width head, it can't be written with a standard-width one.
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.
The only case of this I can think of would be writing a disk with
a wider-than-normal head, so that over a space of more than one full
track of movement, in quarter- or half-track increments, a Disk ][
reads identical data. If anyone knows of any such disk, I'd like
to hear about it.
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.
Of course, discovering exactly *what* needs to be written and *how* to
write it (leaving all other relevant info intact) might take some doing.
All things considered, it sounds to me like we're in "violent
agreement". ;-)
-michael
NadaNet networking for Apple II computers!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it's seriously underused."