Subject: Real Time Scheduling for NetBSD
To: Jason Thorpe <>
From: Erik E. Fair <>
List: current-users
Date: 01/23/1997 11:08:40
At 14:45 -0800 1/22/97, Jason Thorpe wrote:

>I've got a CD-R frob that I'd like to make work, too.  You have to
>send a special command to set up the format for the disc before you
>do any writing, and then the writing is, as I understand it, time
>critical; you can't have jitter.

Perhaps it's time to go through the myriad numbers of papers given at
USENIX over the years on the topic of Real Time Scheduling (and maybe the
IEEE 1003.12 stuff? Those guys were just outta control) and consider adding
a mechanism for real time response to NetBSD's scheduler.

Writing CD-ROMs is not the only thing that will require real time process
scheduling for good results; pretty much any program in the "multimedia"
area (e.g. schlepping sound or video bits to various devices) ought to have
that kind of facility available to it to guarantee performance. I think it
wouldn't be a bad idea for the various X window managers and X servers to
schedule themselves that way for guaranteed good response to the user, too
(frozen mice are not nice).

The MS-DOS and MacOS crowd have this easy - if they need the CPU for
something, the programs just don't give it back until they're done.