Path: utzoo!attcan!uunet!wuarchive!decwrl!ucbvax!techunix.BITNET!devil
From: devil@techunix.BITNET (Gil Tene)
Newsgroups: comp.realtime
Subject: Re: Real-time Platforms by HP?
Message-ID: <9767@discus.technion.ac.il>
Date: 3 Sep 90 20:44:31 GMT
References: <15630009@hp-lsd.COS.HP.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: devil%techunix.bitnet@lilac.berkeley.edu (Gil Tene)
Organization: Technion, Israel Inst. Tech., Haifa Israel
Lines: 23

In article <15630009@hp-lsd.COS.HP.COM> tbc@hp-lsd.COS.HP.COM (Tim Chambers) wri
tes:
>
>I'm curious -- have any comp.realtime readers used an HP computer as a target
>for embedded applications?  How does the HP9000 series 300 (Motorola 68030/40
>CPU) do?

I'm just playing with one now... The 300 differ (badly) from the 800s in
that they do not have a preemptive kernel (So HP says). HP-UX allows you
to define "Real Time priority" levels for processes. Processes with Real
time priorities pre-empt lower priority processes. On 800s this pre-emption
is real, on 300s it works as long as the lower-prio process is not doing
a kernel call at the moment. This means there is no real way to provide
determinism and maximum latency times. If you keep the behaviour in mind
and don't stay in kernel calls long, you can build a pretty good
system with this stuff though.

Gil.
--
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| Gil Tene                      "Some days it just doesn't pay     |
| devil@techunix.technion.ac.il   to go to sleep in the morning."  |
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