floppy imaging

[Fred Cisin]

> > You can read multiple IDs during a revolution (200msec)
> > If you don't get 'em all, put in a different delay.
On Thu, 22 Dec 2005, Tony Duell wrote:
> And what happens if you get a task-switch midway through this?

I've never really felt a need nor desire to run a multitasking OS while
analyzing diskettes.  The best way to multitask is multiple machines.


> I grew up with the WD controllers, and found the 8272/765 a real
> disapointment after those :-)
WD is certainly a better match for what WE like to do.  But the 765 works
reasonably reliably, and is prob'ly just fine for what SOME people want to
do.


> > You can analyze MOST formats by trying to read a 256 byte, a 512 byte, and
> > a 1024 byte sector, such as #2, and then trying the numbers up and down to
> > find first and last.  Won't work for sectors whose numbering don't start
> > with 0 or 1, or ones with invalid headers (such as side B of Kaypro)
> IIRC the sector number is a single byte, so presumably you could try
> reading each sector in turn (0..255) in each size to see what gave no
> errors. I'd thought of doing it that way, but it's going to be terribly
> slow...

If I have my tools available, I read the IDs, read the "raw" track with a
179x, read the track with an option board, and then look at sector
contents.  None of which is on my bookkeeping machine, nor most of my
coding machines.

I'm a little impatient, so if I need to analyze a format without my tools,
I try a "likely" sector number, such as 2 or 3 in each size to determine
the sector size.  THEN I try 0 and 1 to find the lowest sector number,
followed by likely last numbers.  IFF "likely" sector numbers don't work,
THEN I will try brute force of loops to try every possible number.


BTW, although I will gladly discuss techniques with anybody who wants to
make software tools, I will NOT release source code for my retail products
without appropriate formal agreements, (I HAVE had to deal with SALE of
unauthorized copies), and not until I go through and clean it up,
including putting in comments that other people besides myself would
understand.  And, I won't release even the binaries of my in-house
analysis tools until I clean up some known problems, and put an adequate
user interface on them.  If anybody doesn't like that, they are more than
welcome to write their own.

--
Grumpy Ol' Fred     		cisin at xenosoft.com