Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 29 Mar 1995 04:39:49 -0800 (PST)
From:      Fernando Astorga <fernando@cea.Berkeley.EDU>
To:        freebsd-hackers@FreeBSD.org
Subject:   FreeBSD support for realtime systems
Message-ID:  <199503291239.EAA04745@halfmoon.cea.berkeley.edu>

next in thread | raw e-mail | index | archive | help

I was wondering if anyone out there has had previous experience with running
real-time systems on a UNIX environment.  But first, here's a description:

A group in Mech. Eng. department here has developed a real-time scheduler to
control a set of machines in the lab.  Well, since they needed control of
interrupts to execute tasks at a set time, their first implementation was in
DOS and used Visual C++.  As you can imagine, there's been several problems
with this set-up, especially with DOS crashes as students try writing new
programs to control these machines.

The first problem is VC++, but that is being fixed by switching to Borland C++
which is a better compiler.

The next is a bit more difficult.  They want to move this system to run on a
more robust OS, so they've been considering OS/2 and NT.  But these systems
have fixed time slices, making the job of the scheduler more difficult, if not
impossible, i.e. if the interval for a task is less than the time slice.
I think OS/2 has a time-slice of 20ms, way too slow for some of these
applications.

I'm pushing for porting this scheduler to UNIX, preferably FreeBSD, since it
will run on the lab's PCs.  But there are some issues that I'm not too 
familiar with, esp. UNIX's time-slice/process priority system.  Can someone
who has had experience with real-time systems on UNIX provide some info 
on how it can be done?

Thanks.

Fernando Astorga
fernando@cea.berkeley.edu



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199503291239.EAA04745>