Date   : Wed, 08 Jun 2005 11:55:14 +0100 
From   : Littlefield Aaron <CALITTLEFIEL@...>
Subject: Re: GoMMC versus hard drive. Which way to go?

Is there anything on the market that permits an adapter to be used with
GoMMC? What I mean is, is there is something which plugs into the MMC holder
inside the BBC B that either passes through the ashtray hole or through the
vent slots at the rear of the machine? That way you can swop MMC cards at
the rear with the adapter cable going inside the Beeb.

I probably haven't explained that very well but it's essentially an
extension cable! This would permit card swops without unscrewing the casing
all the time.

Aaron
 

-----Original Message-----
From: Majordomo List Manager [mailto:majordomo@...] On Behalf Of
John Kortink
Sent: 08 June 2005 01:11
To: bbc-micro@...
Subject: Re: [BBC-Micro] 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 :( :(

Four ? 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


The Information contained in this E-Mail and any subsequent correspondence
is private and is intended solely for the intended recipient(s).
For those other than the recipient any disclosure, copying, distribution,
or any action taken or omitted to be taken in reliance on such information
is prohibited and may be unlawful.

Emails and other electronic communication with QinetiQ may be monitored.
Calls to QinetiQ may be recorded for quality control,
regulatory and monitoring purposes.