RX02 DMK image to raw tool?

David Schmidt david4602 at gmail.com
Thu Feb 11 12:00:58 CST 2021

On 2/11/21 8:56 AM, Mattis Lind wrote:
> 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?

I wonder if this is an artifact of RX02 disks having sector headers in 
FM, but data in MFM?

> 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?

That's right, for disks detected as RX01 (which are of course fully FM, 
128 bytes per sector).  Sector data that is actually 0xDEADBEEF will 
show up in the .dmk as 0xDDEEAADDBBEEEEFF.

- David

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