Followup British Telecom outage reason

Joel Jaeggli joelja at darkwing.uoregon.edu
Thu Nov 29 20:31:25 UTC 2001


Um... The rtl kerenel runs the linux kernel as a pre-ementible low
priority thread, has proveable worst case timing around 15uSec between
assertion of interrupt and execution of the realtime handler, and is 
posix compliant.

visit:

http://www.rtlinux.org/

and

http://www.fsmlabs.com/




On Thu, 29 Nov 2001, Youse, Chuck wrote:

> 
> You'll forgive me for being cynical here, but I seriously doubt that any
> Linux-derived operating systems could truly qualify as 'real-time'.  To meet
> the requirements for an RTOS, Linux would have to be so heavily mutated that
> it would no longer be Linux.
> 
> Cheers
> Chuck
> 
> -----Original Message-----
> From: Patrick Greenwell
> To: Christian Kuhtz
> Cc: Alex Bligh; Paul Vixie; nanog at merit.edu
> Sent: 29/11/01 07:49
> Subject: RE: Followup British Telecom outage reason
> 
> 
> On Wed, 28 Nov 2001, Christian Kuhtz wrote:
> 
> >
> > > I guess some time someone will realize routers are both
> > > hardware, and software, and shock horror both, if done
> > > well, can actually add value. [hint & example: compare the
> > > scheduler on, say, Linux/FreeBSD, Windows 95 (sic),
> > > and your favourite router OS (*); pay particular attention
> > > to suitability for running realtime, or near realtime tasks,
> > > where such tasks may occasionally crash or overrun their
> > > expected timeslice; note how the best OS amongst the
> > > bunch for this aint exactly great].
> > >
> > > (*) results may vary according to personal choice here.
> >
> > Don't use a non-realtime OS for something that you expect realtime or
> > near-realtime OS functionality.  There are specific systems to address
> these
> > kinds of needs with rather complicated scheduling mechanism to
> accomodate
> > such requirements in a sensible manner.
> >
> > Is IOS a realtime operating system?  No.  Are any of the other listed
> OS
> > realtime operating systems?  No.
> 
> Actually there are multiple Linux-based RTOSes.
> 

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Joel Jaeggli				       joelja at darkwing.uoregon.edu    
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