[Coco] Dos ROMS.

[Phill Harvey-Smith]

Robert Gault wrote:
> Phill Harvey-Smith wrote:
>> <snip> The other problem with this, is once I have added support
>> for things like this I tend to get pestered by people for all the
>> roms it supports, I would of course not hand out copies of a
>> product still being sold, (actually at the mo since I don't own a
>> copy of HDB, that would be impossible for me to do anyways :) ). I
>> could of course flag the rom as optional, which I believe means
>> that if it's there it can be used if it is not it can't :)
> 
> I think you are making this too complicated. Can't MESS be modified
> so that the gui has the option of selecting the disk ROM? Put another
> way, MESS needs the ability to select any ROM file regardless of name
> for the disk ROM.

Not if you want it to be a bios, they only seem to have to be
pre-declared, along with their crc/sha. If Mess was modified so that the
disk cart was mounted like a normal cart then I guess it could be made
to have a specified rom. This makes things more complex tho.

I'm actually talking to one of the people on the mess team about this,
as he would prefer that they where implemented as alternate "bios" sets, 
which I guess would still require them to be pre-defined.

> If the above was implemented, then there is no need to MESS to
> "support" or even know what is used for the disk ROM. It would just
> load it as it currently does for disk11.rom and either the ROM would
> work or not. That's what happens when I use RGBDOS except I'm forced
> to rename it disk11.rom.

Yeah and I bet it complains about the rom being "incorrect", cause it
has the wrong crc :( It probably works ok tho.

Combining replies to two emails....

 > I just tried a slightly different approach to selection of a DOS. I
 > removed the "disk11.rom" entry from the MESS/BIOS/coco3h directory and
 > put DOS10.ROM, DOS11.ROM, RGBDOS.ROM in the SOFTWARE directory.
 >
 > After starting MESS coco3h in Extended Basic, I then mounted any of
 > the above three DOS roms. None auto-started but all started correctly
 > after an EXEC&HC002. All disk operations were correct for any of the
 > roms so mounted.

You are correct, I've just tried this with the the dragon32 driver and 
the superdose6 rom.

It may be possible to have the cart mounting functions recognise a cart 
who's first two characters are 'DK' as all the DOS roms on both the CoCo 
and Dragon, start with 'DK'.

 > The only problems with the above are that these carts must be mounted
 > from within emulation. Emulation will crash if these ROMs are mounted 
 > in the Windows gui as Carts.

This is I believe because at the start of the machine emulation, the 
driver decides what sort of cart is inserted, because it sees a cart 
mounted, it assumes that it is just a simple rom based cart, and 
therefore does not emulate the dos hardware. However loading from within 
the emulator, once the dos hardware has already been detected, may not 
remove it which would explain why this works.

 >				Also Hard Reset within emulation drops
 > back to Extended Basic and the cart is no longer mounted. This last
 > action looks like a MESS bug as that does not simulate a real Coco
 > where the cart might not autostart but it certainly would not pop out 
 > of the cart slot.  :)

It is indeed a bug that I have submitted a bug report for :) It didn't 
used to do this a few releases back.

Since Nathan Woods, has said he would prefer it this way, what would be 
the opinion of the list of having the cart hardware 'mountable', 
obviously, I'd want to have the default being that the CoCo has the 
RS-DOS cart mounted, and the Dragon, has DragonDos, but having them 
seperatly mountable, would have some advantages, eg, you could dismount 
the dos cart to play cassette games, that don't like dos present etc.

The way I would think that this would work is to have a menu for 
selecting the cart type RsDOS, DragonDos etc, and then you would use it 
with a rom mounted by the normal rom mounting method, this could 
possibly be defaulted, so that by default, if you mount the RS-DOS (on 
the coco) cart with no rom specified then you would get RS-DOS 1.1 etc ?

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.