Re: System beep ignored?

[dempson@actrix.gen.nz (David Empson)]

Nathan Mates <nathan@visi.com> wrote:

> In article <Pine.SOL.3.95.961002210240.18840A-100000@general3.asu.edu>,
> Adam Myrow  <adam.myrow@asu.edu> wrote:
> >     How come when you assign a sound for the standard beep under system
> >6.0.1, it's ignored under ProDOS 8?  I can understand such sounds as "disk
> >ejected" being ignored but why the system beep?  Anybody know? 
> 
>    Because under GS/OS, the system beep is a patchable call to the
> toolbox, and can thus be rerouted to do anything you want. Under
> ProDOS 8, the beeps are almost always generated by a call to a
> ROM routine, which is MUCH harder to patchout.

No problem at all.  The ROM-based beep routine ($FBDD) is vectored
through BELLVECTOR ($E1/006C), which normally points to the routine
which generates the standard "thunk" noise.

Some part of System 6.0.x patches this vector to a routine which allows
the beep to be reconfigured (associated with the Sound Control Panel).

It seems that while GS/OS is active, this routine allows the
user-selected sound to be generated, but under ProDOS-8 it always uses
the orignal noise.

I can't think of any good reason for this, except that playing an
arbitrary sound may require more complicated interaction with the
Ensoniq, and this could interfere with ProDOS-8 sound software.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand