Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!rpi!crdgw1!ge-dab!puma!andrew.ATL.GE.COM!jnixon
From: jnixon@andrew.ATL.GE.COM (John F Nixon)
Newsgroups: comp.os.misc
Subject: Re: (Free) book on the Amoeba distributed system available
Message-ID: <240@puma.ge.com>
Date: 26 Mar 90 14:14:49 GMT
References: <6067@star.cs.vu.nl> <2604@quiche.cs.mcgill.ca> <6106@star.cs.vu.nl> <2629@quiche.cs.mcgill.ca>
Sender: news@puma.ge.com
Lines: 45

utility@quiche.cs.mcgill.ca (Ronald BODKIN) writes:
:In article <6106@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:
::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.  
:	You are wrong.  You can access another machine this simply:
:[2] ls
:	This would perform (on machine 2) an ls command.

I think you are missing the point.  Although the original statement doesn't 
make it clear, the tone of Tanenbaum's article is that you simply don't
see "machines", either remote or local, or have "defaults" to a particular
machine with Amoeba.

:For example, if your user directory is
:on machine 1 and you login through machine 2, ls will list the directory
:on machine 1 automatically.

This sentence shows that QNX has the property that "machines" show
through.  The distribution is not completely transparent.

::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. ... 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?
                       ^^^^^^^^^^^^^
:	QNX is essentially like this.  The file structure is invisible, one
:does have an open pool of resources (tasks spawn and communicate across the
:network as easily as they would on one machine -- the same set of tasks that
:work on a single machine will distribute across a network with no
:modification) ...

The key word is automatically.  I may be wrong, but it sounds like QNX
doesn't distribute automatically; it takes some involvement by the program
or the operator.  Would two runs of the same set of tasks use the same
set of machines?  

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jnixon@atl.ge.com                    ...steinmetz!atl.decnet!jnxion