MMC & CF memory was Using 3.5" HD drives on CP/M systems

From: Randy McLaughlin <randy_at_s100-manuals.com>
Date: Wed Feb 2 13:56:39 2005

From: "Cameron Kaiser" <spectre_at_floodgap.com>
Sent: Wednesday, February 02, 2005 1:30 PM
>> > Hmm, maybe; maybe not. A Beeb enthusiast named John Kortink has
>> > produced an MMC interface for a BBC Micro.
>>
>> The same chap has also built a device, sold commercially, called
>> ViewFinder which allows certain AGP graphics cards to be connected to
>> the Acorn RISC PC's podule bus, complete with accelerated RISC-OS
>> display drivers. Quite a coder.
>
> Someone is also developing an MMC card reader for the Commodore 64.
> Individual Computers, the ones who are backing the C-1 project, are
> reportedly working on releasing it this year.

MMC is a snap to implement, the only "problems" are efficiently driving it
at a reasonable speed and they are 3.3v. MMC uses a very simple serial
interface where every bit is clocked in or out by the host system. It can
be done entirely in software by shifting each bit in or out but then it is
sloooow.

CF's can be directly wired to an IDE interface and since it is a 16 bit
parallel interface it is easier to get much better speed and are 5v
tolerant.

Writing to Flash devices is relatively speaking slow, this is simply because
of the time to burn the data. Of course there is no "seek" time as in
mechanical mass storage system.

While CF's have a faster interface I like the fact that MMC's require so few
connections.


Each device has it's own problems but the are so small, require so little
power, easy to interface. I like them for classic systems the storage is
small compares to 200gb drives but large for classic systems.


Randy
Received on Wed Feb 02 2005 - 13:56:39 GMT