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

From: <(>
Date: Wed Feb 2 13:32:28 2005

> > 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.

What kind of protocol that MMC talks in serial fashion?
> 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.

Again, correct and in IDE mode it behaved exactly like a IDE hard
drive. I have done that, and does work on older machines as well.

> 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.

yes, Time have changed, Look for Ultra II (SanDisk) series, Lexar
Pro series with WA acceleration. Very close to HD speeds like 500MB
hd that used to be. (over 40X and higher).

Even speedier CF cards is due to come out shortly.

CF is perfect as IDE drive substitute for machines or portables:
quietness and on portable it is a BIG bonus that current draw is
under 0.3W even it is writing. Yes, Point three watts. Lowest
power 2.5" HDs (normal operation) that spins is currently above 3W,
and that is very few that has this specs. Most average 5W or so.
But the writing & reading with seeking is very transitiional (usually
1W to 2W extra spikes and lasted few milliseconds).

> Randy


Received on Wed Feb 02 2005 - 13:32:28 GMT

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