Re: Recode to Play MP3?

[mdj <mdj.mdj@gmail.com>]

On May 20, 5:31 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> Michael Kent wrote:
> > Michael J. Mahon <mjma...@aol.com> wrote:
>
> >>Michael Kent wrote:
>
> >>>schmidtd <schmi...@my-deja.com> wrote:
>
> >>>>I wonder if Dave Schmenk's 30% faster CFFA firmware would help?
>
> >>>It doesn't look like it.  His firmware doesn't seem to affect GS/OS
> >>>access, and both Oversampler and LongPlay are GS/OS programs.
>
> >>Have you installed Dave Lyons' GS/OS CFFA driver?
>
> > Yes.
>
> I wonder if the read (and/or write) speed of the CFFA is influenced
> by the speed of the CF card?
>
> Theoretically, a "1x" card would support 150KB/sec, so unless there
> is something peculiar going on, *any* CF card should be about as fast
> as an Apple could transfer data--and much faster than the 11kB/sec
> that sampled sound would require.

It seems the CF cards have unusually long setup times for data
transfer that considering the typically small IO transactions that
Apple II's do, severely impacts the total I/O throughput you can
achieve - apparently to the degree that even 1980's class hard disk
drives can outperform it.

The hardware design of the CFFA would need to incorporate some sort of
asynchronous buffering that enabled the CF card to be read and filling
a buffer while the card firmware emptied it.

I've not looked at the CFFA's design in detail, but I'm fairly certain
it doesn't utilise a technique like this, and as a result manages only
modest data transfer rates.

Matt