RX02 DMK image to raw tool?

[Mattis Lind]

Den mån 8 feb. 2021 kl 20:39 skrev David Schmidt via cctech <
cctech at classiccmp.org>:

> On 2/8/21 1:00 PM, Mattis Lind wrote:
>
> I wrote my own, not knowing where another one lived.  I happen to think
> in Java, so that's what it's implemented in.
>
> Description is here:
>
> https://github.com/RetroFloppy/transformenator/wiki/Utility-Functions#dmk2raw
>
> Code is here:
>
> https://github.com/RetroFloppy/transformenator/blob/master/src/org/transformenator/util/Dmk2Raw.java


Thanks! I will have a look.

>
>
> The only thing of interest is the cw2dmk tool would read RX01 disks and
> "double" the data - so my tool will make an attempt to detect that and
> halve the data back out the other end.
>

After sending my message I did some hard drive archeology and found the
dmklib I downloaded five years ago. There were some adaptations to handle
RX02 format and it worked quite well. At least when the disk has been read
error free.

However the version of cw2dmk (4.5)  I used had a feature that joined
sectors from multiple reads. That should be quite useful to try to stitch
together many reads worth of data into one full error free track. But for
some odd reason cw2dmk v 4.5  joined sectors which were FM encoded, even
though I explicitly stated I wanted only RX02 encoding,  resulting in a
track with both FM and RX02 (mixed FM and MFM) sectors. I cannot really
understand how that could result in a good read and a matching CRC?

Now I see that there is a version 4.6 of these tools that I probably should
try instead. Perhaps the join feature works better in that version?

So cw2dmk reads FM disks and doubles every byte? Resulting in 256 bytes
sectors in FM mode, right?

/Mattis




>
> - David
>