Date   : Wed, 08 Jun 2005 02:10:39 +0200
From   : John Kortink <kortink@...>
Subject: Re: GoMMC versus hard drive. Which way to go?

On 07 Jun 2005 23:56:07 +0100, Jonathan Graham Harston wrote:

>> Message-ID: <5kf9a1tebpjcrrbihk272iodajjkkno7rn@...>
> 
>John Kortink <kortink@...> wrote:
>> With GoMMC, easy to backup as well. You can regularly
>> make a backup copy of your harddisc image on your PC.
>> Even large ones like hundreds of MBs will be a matter
>> of a few minutes' work to backup.
> 
>Ah, the other advantage/disadvantage between GoMMC and HD.
> 
>The MMC card unplugs from the GoMMC quite easily (+), but is
>often hidden inside the computer.
> 
>A hard drive can be fiddly to unplug, but with a BBC/Master is
>often outside the case.

True. But simply leaving the beeb's cover unscrewed is
enough to have quick access to the MMC card if needed.

Of course, the real tinkerer has the cover off completely,
24/7. ;-)

>> >Why won't it work in the ashtray though? Surely it's just another rom
>> >socket, electrically,
>> 
>> No, it isn't. It's quite different.
> 
>A Master ROM cartridge card subtly changes the signals available
>on the cartridge slot, so plugging something into a catridge card
>ROM socket is not identical to plugging into a motherboard ROM
>socket.

But the 'ashtray' is the beeb thing, remember ?

>Also, the signals actually available are subtly different to the
>signals available at the ROM sockets on the motherboard.
> 
>I've been meaning to carefully destroy a ROM cartridge to see if I
>can modify it to present the correct signals to a GoMMC. I miss my
>four banks of sideways RAM :( :(

=46our ? I presume you mean two. The other two are still
available. As would be RAM banks on cartridges (e.g.
via Sprow's cartridge replacement ?).

I think I have made the B+ version of GoMMC (this does
everything with read operations only, no writes) run in
a ROM cartridge at one stage. I think it wasn't stable
however.

It has to be said that none of the cartridge hardware
I've examined so far has been particularly careful to
drive the data bus only when needed, which may explain
something.

IMO it's not worth pursuing any of this, because two
RAM banks are still available, more via cartridges
if needed.


John Kortink

-- 

Email    : kortink@...         
Homepage : http://www.inter.nl.net/users/J.Kortink