Date: Fri, 6 Apr 2001 08:02:09 -0400 (EDT) From: Daniel Eischen <eischen@vigrid.com> To: Robert Watson <rwatson@FreeBSD.ORG> Cc: Brett Glass <brett@lariat.org>, John Baldwin <jhb@FreeBSD.ORG>, Johann Visagie <johann@egenetics.com>, Freebsd-chat@FreeBSD.ORG, Dag-Erling Smorgrav <des@ofug.org> Subject: Re: corporate announcement Message-ID: <Pine.SUN.3.91.1010406075759.3756A-100000@pcnet1.pcnet.com> In-Reply-To: <Pine.NEB.3.96L.1010406012504.46990H-100000@fledge.watson.org>
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On Fri, 6 Apr 2001, Robert Watson wrote: > > On Thu, 5 Apr 2001, Brett Glass wrote: > > > At 11:45 AM 4/5/2001, John Baldwin wrote: > > > > >The pathfinder ran on a version of VxWorks. > > > > Yes. Though it was reported at the time that the system was unstable and > > had to be rebooted by a watchdog timer at regular intervals. > > Fortunately, the embedded system designers who created the probe were > > smart enough to build one in. > > My understanding is that that was a result of an application bug rather > than the OS, and had to do with a priority inversion. However, the > article I read is pretty distant in my memory, so some references would no > doubt be useful. Yes, it was an application bug. It failed to use an priority inheritence mutex (in VxWorks speak, an inversion safe semaphore). See: http://www.cs.cornell.edu/cs614-sp98/papers/pathfinder.html -- Dan Eischen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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