Subject: Re: VMU device node ideas
To: Marcus Comstedt <marcus@idonex.se>
From: O'Shea. Shawn <shawn@eth0.net>
List: port-dreamcast
Date: 02/09/2001 17:22:49
> 
> This should probably be handled the same was as e.g. USB/Firewire
> storage devices (whatever way that is, I'm no BSD guru either...  :)

I was thinking of this whole idea this morning before this thread started,
but I was thinking the same thing (that it would need to be like USB).
Anybody know how the Nexus 16M cards work? Is that 16mbit/8bits in a byte
== 2mbytes??? 2mbytes is pretty decent for a mini self hosted system if
you were to boot off a cd. (Then maybe you could software RAID them
together 8-)

-Shawn

> 
> 
>   >> So, maybe (partition*24)+(port*6)+slot?  Or is it better to have
>   >> bitfields, like (partition*32)+(port*8)+slot?  Some other order?  (I
>   >> think partition should go at the top anyway, since you'll only be
>   >> using partition 0 in practice.)
> 
>   J> Makes sense, but I suspect at the top you meant port*4. (4 ports, 6 slots.)
> 
> No.  6 slots, therefore port*6.  If it were port*4, both port 0 slot 4
> and port 1 slot 0 would get minor number 4.  You would out the math.  ;)
> 
> 
>   J> I'd go with the bitfield version-- you'll need 3 for the slot, 2 for the 
>   J> port, and 5 for the partition, which puts you still well shy of the million
> 
> 8 bits for partition.  256 partitions, remember?
> 
> 
>   J> mark. Having a few extra might be useful for future development (perhaps
>   J> Dreamcast 2 will have 8 controller ports?), so perhaps something more like
>   J> 4 for the slot, 4 for the port, and the rest for partitions would be a 
> 
> Rather than trying to support more ports, having some bits for maple
> bus number would be a better idea.  The way the protocol works, there
> can't be more than 4 ports, but there could theoretically be multiple
> maple buses (so an 8 port Dreamcast could be made by having two buses
> of four ports each).
> 
> 
>   J> better bet. Hm, or would having extras now get confusing? Is there a 
>   J> hardware spec for how many controller ports the console could support? 
>   J> (After all, it seems you can have 6 slots on a port even though you can 
>   J> only fit two memory modules in a normal controller...)
> 
> The controller also counts as a slot.
> 
> 
>   J> <lurk>, and perhaps it's not even worth real salt, make it shakers of 
>   J> potassium chloride.
> 
> I prefer ammonium chloride.  *yum*
> 
> 
>   // Marcus
> 
> 
> 

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