Reading various format 5.25" floppies on

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Mon Jun 16 17:56:01 2003

> > Always start by being clear about whether you want to
> > duplicate a diskette of the other ("alien") format
> > read/write an image of the alien diskette

On Mon, 16 Jun 2003, Tony Duell wrote:
> In general, if a PC (say) is capable of duplicating a disk, then it's
> also capablie of recoridng and rewriting a disk image (this just involves
> saving the data that would have been transfered from the source to
> destination disks in a normal PC file of some suitable format). So this
> is a simple-ish matter of programming
And without that simple-ish matter of programming, you end up wasting way
too much of your time fielding tech support questions from those who don't
have the software.
Without the additional software, they turn into completely different
tasks.

> > read/write files from the alien diskette
> This, again, can be done in software if the disk is physically readable,
> but it involves and understanding of the filesystem involved...
> > Use files from one program in another program
> Again software, but geting documentation on application files can be
> 'interesting'...

Yes, the difference IS software. I'm sure that I'm not the only person to
be stuck with tech support for users who do not have the system software
that they need.

> > ON A PC, using the PC hardware, a PC CAN NOT READ ANYTHING other than
> > "Western Digital" style MFM sectors on a PC, using PC hardware,
> Even then you might have problems. There is an index timing problem that

The statement that you "CAN NOT READ ANYTHING other than" is not
invalidated by the existence of ADDITIONAL problems.

> means the Intel disk controllers can't read some disks formatted by real
> Western Digital chips (if the first sector header starts too soon after
> the index pulse, the Intel controller won't see it). Some clone disk
> controllers mighy have got this right, some certainly haven't!

In addition, there are some other minor complications, such as additonal
code needed to read 128 byte sectors, disks (such as Kaypro DS) that have
invalid content in sector headers, etc.

> > Each handles a fixed finite group of formats. Most have provision for
> > adding in additional formats yourself, but almost nobody ever succeeds in
> > doing so, and after fielding too many "which numbers do I put in to make
> I have mananged to add a new CP/M format (FTS-88 double density 8") to
> 22disk, I think.

It CAN be done. I had already assumed that Tony dould do it. _Most_ end
users of such programs do not have ("almost nobody") the knowledge needed
to do so. And when that option wasn't hidden in XenoCopy, we got
constant phone calls demanding help in using that feature to add formats
that we had already told people were IMPOSSIBLE with their hardware.
("which numbers do I put in to do Apple?") What was worse, was that in
the few cases where people WERE successful, they wouldn't give us the
specs (nor sample disk) to be able to add the format to the program
for other people. We had no interest in helping people add a format that
they wouldn't share. The capability stayed in, but became "undocumented".


> Is it _possible_ to add formats to Hypercross? I have the original disks
> and manaals for the Model 4 version, and it doesn't say it is. If it is,
> what's the trick?

Probably not. ("_Most_ have provision") I haven't heard from Mike Gingel
in almost ten years; is anybody still in touch with him?

In some programs that don't have deliberate provision for adding formats,
it may still be possible to decipher the data storage and step on the
numbers in the file to change a format to something else.
Received on Mon Jun 16 2003 - 17:56:01 BST