Re: [9fans] cpu server

[Charles Forsyth <forsyth@terzarima.net>]

>>That is correct Bruce. A single P9 box is brain dead, it is unable to
>>demonstrate -any- of its advantages over a traditional OS.

actually, i don't think that's quite right, if you look at the construction
of many of the services, for instance.  initial design is often
given a focus by thinking about possible use of the name space and
then the design or structure of that name space; when it makes sense,
the consequent split into name-space provider and name-space user(s)
can simplify application structure, regardless whether distribution is
involved or not.  thus, there is still advantage in its use and significant
difference with more `traditional' systems.

now, a message-passing system (say) will obviously encourage
applications to be based on message-passing, but plan 9's name space
sits at a higher level of abstraction than message-passing (or soft
SOAP), and therefore comes in at a higher level of application design
(i'd say).   use of name spaces is encouraged and
supported by mechanisms deeply embedded into the system itself.

acme provides a good example of using those ideas on a single machine.
it's a file server but that's not primarily for reasons of
distribution, and indeed i haven't seen much use of its services being
subject to import or export (though they could be).  its activity is
usually confined to a single box, but it's still an advantageous
structure.  that's why i often call it an `integrating' not an
`integrated' environment.  the latter tend to be self-contained (i
know, i know.  `plug-ins', where you have to come to grips with deep
knowledge of the IDE's internals).  acme is much more open-ended, and
i shouldn't think the typical acme client has any idea or need to know
what acme looks like inside.

keyfs and factotum similarly simplify the interface for their clients,
by being name space servers, again in a different way from traditional OSs.
(implementation of the service itself is also given focus by its being a file server.)

of course, you're right that there is still greater power once the name
space is available across a network.
one of the interesting things about the Vita grid work to me
was how representing things in the name space
led to a simple yet flexible interface from the client's point of view.
it's described in terms of reading and writing a few files,
and it's natural to describe the protocol for the use of those files.
i wasn't involved in the design or implementation, but
i found it easy to see what a new client had to do,
much more so than with the more traditional API/ABI descriptions.