Re: SpeedDOS

Hallo allemaal,


I had a weird day today. I started to disassemble one of the 
SpeedDOS ROMs for the C64 I have. Note: the ones I had so far I got 
from internet. Of course I focussed on the parts different from the 
original Kernal (V3 in this case). But some of it simply didn't make 
sense: branches to the middle of an instruction, jumps and calls 
that led to nowhere (in the end). Some instructions even accessed 
the memory at $1800 and $1C00. That would make sense if I was 
dealing with a 1541, but not in a C64. Unless it is code that is 
meant to be sent to a 1541. But why, having its own SpeedDos ROM as 
well?
I compared this ROM to other ones I had. Although different, they 
had these weird instructions as well. What to make of that?

So I decided to check my own two systems. My first problem: my 
database was incorrect :( My C64C /1541-II combination was found 
very soon. The Brotkasten/1541 wasn't. Looking for the Brotkaten I 
stumbled upon another C64C with SpeedDOS. Then I found my 1541 
connected it and... didn't work. Pressing @ after a reset showed 
that this wasn't a SpeedDOS 1541 but one with equiped with Dolphin 
DOS 2. I didn't even know I had one! (yes Patryk, you can laugh)
So I went searching for all 1541s with a cable and so I found my 
1514 with SD plus three others with a cable. And of these three 
again one was with DD2. Where did these DD2s come from ??? I really 
cannot remember. 

So now I got three 1541s with SD, all V2.7. And most important: they 
all worked fine with the second C64C. Interesting detail: there were 
two different SpeedDOS versions on board of the C64: one said 
'SPEEDDOS +' and the other 'SPEEDDOS ++' in the title. I don't know 
if this is original because the rest of the title was havily 
custimised. The second version was at least twice as fast and 
wouldn't load at all if the parallel cable wasn't connected. 
Familiar to anyone?

Anyway, I was able to read out the various EPROMs. Both the drive as 
C64 ROMs were quite different from the ones I already had. And now  
I know taht these BINs come from confirmed working systems, I will 
pay my attention to these first.


About my C64C /1541-II combination: it worked fine. But the drive 
wouldn't cooperate with the other C64C. And it seems that its ROM 
has been changed because it says 'KLAUSDOS'. I haven't combined this 
C64 with the other drives yet, will do that tomorrow. I also will 
read out their EPROMs as well.

To be continued....


--
   
Kind regards / Met vriendelijke groet, Ruud Baltissen
www.Baltissen.org







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