Path: utzoo!mnetor!frank
From: frank@mnetor.UUCP (Frank Kolnick)
Newsgroups: comp.os.misc
Subject: Re: (Free) book on the Amoeba distributed system available
Message-ID: <5327@mnetor.UUCP>
Date: 23 Mar 90 14:59:24 GMT
References: <6067@star.cs.vu.nl> <2604@quiche.cs.mcgill.ca> <6106@star.cs.vu.nl>
Reply-To: frank@mnetor.UUCP (Frank Kolnick)
Organization: Computer X (CANADA) Ltd., Toronto, Ontario, Canada
Lines: 44

In article <6106@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:
)In article <2604@quiche.cs.mcgill.ca> utility@quiche.cs.mcgill.ca (Ronald BODKIN) writes:
)>Sounds like Amoeba is quite close to QNX.  QNX also has the virtual machine,
)>the same kernal design, the same high-speed features.  And QNX has years
)>of a good track record.
...
)I thought QNX was basically a UNIX-clone.  You log into one specific machine
)and work there, with access to others via rlogin and explicit file motion.
)Correct me if I am wrong.  
)
)In Amoeba you just log in.  When you say the equivalent of ls -l, you see
)a bunch of files.  Some might be in your machine room, and the rest might
)be spread over a dozen sites in as many countries.  You can't even tell
)where they are unless you look hard.  When you start make, it runs all
)the compilations on as many processors as it can find, in parallel.  This
)is what I mean by a distributed system--there is no concept of a home machine
)where work is done by default.  There is just a big pool of resources which
)the system allocates automatically.  Is QNX like that?

While QNX is not a UNIX clone, it does provide a standard C library and
a number of utilities which loosely correspond to UNIX'. Their micro-kernel
is also unique, and the overall architecture of the system bears no
resemblance to UNIX. The network is part of the architecture, such that you
can send messages between nodes and access remote files without 'logging in'
to the other nodes. However, it does not have the level of transparency
that Amoeba appears to have, although there's no technical reason it
couldn't. The standard 'make' runs on a single node, but Quantum also
provides a 'team make' which distributes the load to the available nodes.
(One of the demos in our windowing system for QNX generates a Mandelbrot
by assigning slices to different processors -- fun to watch.)
In any case, it would be interesting to compare the two systems.
(It would also be interesting to compare it to Motorola's cXOS,
which is a distributed o/s with a different philosphy than QNX', but
with much the same goals: real-time response, etc. cXOS, for example,
has the concept of a 'single virtual machine', i.e., all of the nodes
together look and behave like a single computer. QNX doesn't go quite
this far. Sounds like Amoeba does, perhaps even more so.)



-- 
Frank Kolnick,
Basis Computer Systems Inc.
UUCP: {allegra, linus}!utzoo!mnetor!frank