Event-driven API

Event-driven API

Posted Jun 19, 2007 8:35 UTC (Tue) by Jel (subscriber, #22988)
Parent article: User-space device drivers

This all sounds pretty horrible. Back in '83 or '84, the Amiga came out,
with a much nicer, event-driven device API. At least from the client
side, it was just a matter of sending events. So, say, for the narrator
device, you would send something like { SET_PITCH, ..., 2000 }, and it
would set the pitch of the speaker's voice. This was asynchronous of
course, so it worked really well with devices like SCSI units/buses.

Presumably the server side was basically just registering a message queue,
and waiting for instructions.

This wasn't a memory-protected kernel, but if we're talking userspace
anyway, then it shouldn't matter. The OS was fully multitasking, and
fairly real-time for the day, as I understand it.

Why not use a model like this?

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