Re: IAC driver problems
Re: IAC driver problems
- Subject: Re: IAC driver problems
- From: Doug Wyatt <email@hidden>
- Date: Fri, 23 Jan 2004 17:15:11 -0800
On Jan 23, 2004, at 16:42, X. J. Scott wrote:
Yes, I'm one of the other persons so I'll make myself known and
confirm this
publically. What I see is that sysex packets of greater than 256 bytes
contain random data after the 256th byte UNLESS the IAC port is being
observed with MIDI Monitor, in which case Heisenberg arrives and makes
the
data transmit cleanly.
I would assume this has something to do with a plain MIDIPacket being
allocated on the stack in the IAC code somewhere since it defaults to
256
bytes long. Larger packets are supposed to allocate a bigger buffer or
break
it into multiple packets.
I've written a bug, but if you'd like to write one, you'll get notified
when it's fixed ...
Another possible bug is that when you create a new IAC port, it makes
your
MIDI driver go off-line (dimmed, all ports connected vanish) until you
quit
all CoreMIDI apps and relaunch. This is with the MIDISport driver, so
it
might be an issue for Pete Gontier to look into. The IAC works by
creating a
new hardware device and not a new set of virtual ports, so maybe the
driver
is not able to handle new hardware devices appearing willy-nilly.
I'm fairly sure that's a driver issue -- do you have the latest? Does
the device also go offline if you choose Rescan? I bet it does. All
that AMS's Rescan does is make a call to CoreMIDI to stop/restart all
the drivers. AMS also does this when changing the configuration of the
IAC bus.
Also, I was able to infer the IAC's purpose and use since I was
familiar
with the OMS IAC design, but user-level documentation on the IAC device
would probably be helpful for musicians.
That would be another good bug to write ...
Jeff, thanks for the details.
Doug
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