NFS question

NFS question

Post by Tejas Arun Kokj » Fri, 17 Sep 2004 05:17:16



Hi,

I don't know if this is the correct group to post this question.

I wanted to know that why does NFS use RPC and not Distributed
Shared Memory (DSM) ?

What are the drawbacks if NFS is implemented using DSM ?

Tejas Kokje

 
 
 

NFS question

Post by Allen Kistle » Fri, 17 Sep 2004 11:30:44



> I don't know if this is the correct group to post this question.

> I wanted to know that why does NFS use RPC and not Distributed
> Shared Memory (DSM) ?

> What are the drawbacks if NFS is implemented using DSM ?

I would suggest comp.protocols.nfs.

 
 
 

NFS question

Post by Juhan Leeme » Sun, 19 Sep 2004 02:36:34



> I don't know if this is the correct group to post this question.

> I wanted to know that why does NFS use RPC and not Distributed
> Shared Memory (DSM) ?

Maybe because it was designed and implemented about 20 years ago? It was
supposed to be simple, rugged, and transportable (easy to port), so that
many different kinds of computer systems could share files with NFS.
...and if it works, why*around with it and risk breaking it?

Quote:> What are the drawbacks if NFS is implemented using DSM ?

I don't know what DSM is. I've never heard of it.

When I search using Lycos, I get some home pages on the web. Then when I
tried selecting one (INRIA, in France), I get a 404 (not found). Doesn't
sound like any kind of NFS that I would want to use.

Then some other pages do describe distributed shared memory. Sounds (like
the name suggests) that this was designed to share computer memory between
parallel processing nodes? That is slightly different purpose than sharing
computer files between networked computers, that may or may not be
collaborating on parallel computing jobs. Presumably one could be mapped
onto the other, but at what cost? with what advantage? Shared memory would
be more concerned about fine grained coherency across nodes wouldn't it? I
would expect greater overheads and therefore less throughput with DSM.

Maybe turn the question around? Why should I care about DSM? What does it
promise and deliver that would make anything (like NFS) better?

I would guess there is nothing preventing anyone from implementing (some
version? enhancement?) of NFS using DSM. There is already a TCP
enhancement of NFS, which ISTR was originally only UDP. The next trick
would be to convince other people to use your enhanced NFS. Promotion!

--
Juhan Leemet
Logicognosis, Inc.

 
 
 

1. NFS question, Picasso question

Hi,

I have a '486 running Linux and an A3000 running NetBSD-1.1.
If I try to mount the Linux machine onto the BSD one it does
themount, I can read and I can write as well. However, I can not
create files.
That is, everything else (permissions) being ok, I can touch an existing
file on the linux box, I can append to it but I can not create any new files.
This seems like as if the directory files would be r/o everything else r/w.

The linus side is probably OK, because all mount stuff works with other linuxes
and even with the Amiga AmiTCP package.

Next question, I converted my Picasso-II setup using the provided tool
(Gateway CD, NBSD-1.1) to grfconfig mode file. None of the modes other than
the 1 bit deep ones are accepted by grfconfig. What could be the problem ?

Thanks in advance,

Zoltan
--
*****************************************************************************
* Zoltan Kocsi                      *    I don't believe in miracles but    *
* Bendor Research Pty. Ltd.         *    I rely on them.                    *
*****************************************************************************

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