Re: 1541 ROM areas recognition

On Saturday 09 November 2013, you wrote:
 
> - someone on the other side of the globe tells me that he’s got a strange,
> non-standard drive - I ask him to read the error channel. He reads the 73
> message and it says “TURBO CORBA V4” - he’s got neither will to rip the
> drive apart, nor technical knowledge enough to analyse the circuit and
> find out where the ROMs are addressed nor any tool to read the removed ROM
> chips out
> 
> I’d like to send him the program (not knowing what the “turbo cobra v4” is)
> and get exact rom dumps back

yeah, have a similar situation with cartridge dumping (although it doesnt 
happen so often anymore that completely unknown hardware pops up). i have 
written a couple of small dumper programs for that, and when someone has an 
unknown cartridge we ask them to run those programs and mostly get a useful 
dump that way :) in those cases when it doesnt work, we'd analyze what we got 
and then try to work out a proper way.
 
> > so well, what i'd do in the drive would be (in this order)
> > - check the error channel/poweron message. fortunately those drive
> > extensions that added more than just a different ROM were not cloned a
> > lot, so this should give a good hint on wether there is someting like
> > dolphin dos 3
> 
> 73 says strange things sometimes. The lame rippers/cloners routinely put
> whatever they thought would look c00l..

true... huge problem with eg speeddos :)

> > - do a ram/rom check. after that you know for certain what cant be ROM
> > because it is either RAM or i/o (ie, a value written can be read back)
> > - do empty i/o check, ie read blocks and check for $ff
> > - probe for i/o chips at known locations
> > 
> > additionally, maybe try to find some specific ROMs at known locations and
> > check by checksum - things like dd3 should be detectable that way
> 
> I think I’ll try something along those lines. I am afraid however that I
> may for example hit some unknown chips and lock the machine up (not
> permanently I mean but enough to render the program useless) by writing to
> them.

there is always a risk with probing for unknown hardware, indeed - i'd try to 
write the detection in a way that it will work with all "major" extensions, 
and then hope for the best =) in practise there are probably just a handful 
configurations.

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