Subject: Re: [linux-audio-dev] more fundamental questions
From: Jay Ts (jay_AT_toltec.metran.cx)
Date: Tue May 22 2001 - 20:51:28 EEST
Paul Davis wrote:
> Jay Ts wrote:
> >I consider MIDI support to be nearly essential, because it is needed
> >for at least the following:
>
> Jay - MIDI I/O does not need to be done via Ports. There are other,
> possibly more flexible options available.
Ok, cool then. Whatever works out for the best.
> However, I agree that it
> would be nice in principle to have MIDI data be exchangeable within
> LAAGA as well as audio.
I did a little more thinking on this and realized that MIDI is essentially
a control signal, and maybe it would make sense, in a general way, to
include control signals in the design in addition to audio, and then
make MIDI (or some cooked version of it) a class of control signal.
I think the control signals are important, because this comes up
so frequently and in such fundamental ways in computer technology.
Think of it:
- at a very low level in computers, in the CPU's data path, there
are busses for data, and lines (wires) for control signals. The
control signals are necessary to direct where the data is going to
and coming from and also what microcoded operations to apply.
In a simpler manner, this data/control dualism also exists in memory
chips and other digital circuits.
- at a higher level, there is the concept of a von Neuman architecture,
in which data is held by memory, and the CPU is more about what
to do with the data.
- at a higher level, we have software divided into data and instructions
(text and data segments of programs, and applications that operate on
data files or "documents").
Meanwhile, audio equipment generally have both "data" (audio)
and "control" (front panel knobs, buttons, and MIDI In/Out) signals.
So I think based on general principles alone (if not real world examples)
it makes sense to follow this model.
(I hope I explained myself clearly ... not sure ... tired. zzzzzzz.)
- Jay Ts
jayts_AT_bigfoot.com
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