RFS vs. NFS (really Locus and AIX)

[Barry Shein]

>With any luck, I've worded everything carefully enough that I
>will still have a job in the morning.

Funny how IBM brings that out in people...

I went to two separate presentations by two separate groups a couple
of weeks ago. One was on DS and the other was on LOCUS (all w/in the
AIX context.)

DS is another in the series NFS...RFS...(etc)FS. It basically is a
stateful remote filing system with a promise to preserve things like
locking semantics. Currently it's only available on an SNA transport
but there were plans (I believe approx. dates were given) to make it
available on Internet protocols and ethernet and all that stuff.

It wasn't at all clear that there was any intention to make it
available to non-IBM vendors other than the usual "we are considering
that" (or is the practiced wording "that would be a logical thing to
do...".)

LOCUS was available on 370 Architecture and PS/2's (model 80's? I
don't remember, but '386.) It seemed one of the major uses was that
you could put binaries on either system (370 or 386) compiled for
either (got that?) and it would figure out which it should run on.  As
well as a single file-system view (I don't think this was meant to be
quite NFS'ish, more like the sum of the machines is the whole.) There
was some small limit (at least for a 3090/200 like ours) of PS/2's you
could hook up (31?) tho the conversation turned to setting up M
thingamajigs of N each and then everything went blank.

One use presented was to attach ASCII terminals (or even come in over
an ethernet from a workstation) to the 386's and use them as front end
concentrators. The idea would be that you could run (eg) a full-screen
editor on the local PC host against files on the 370 and otherwise
proceed as if you were working on the 370. This seemed like a useful
idea (how well it all works I have no idea, there was no demo) as IBM
mainframes really hate full-duplex style interfaces, so let the PC
handle it. Note that all previous releases of Unix (IBM, Amdahl, AT&T)
required some sort of special equipment to accomplish full-duplicity
(eg. Series/1, modified 4705 etc.) So this aspect is right in line and
could be better than buying a bunch of Series/1's anyhow.

Fortunately they (IBM) did include support of NFS over Internet
protocols (ethernet etc.) The DS looks like an uphill battle,
particularly in environments like my own where we have probably 100+
systems running NFS in an heterogeneous environment. I'm not certain
the world really needs yet-another-remote-file-system, but I'm sure
the market will decide. At any rate, I have no doubt there are more
than a few IBM systems out there w/o any NFS and plenty of SNA and
this will, I presume, look attractive to them.

I dunno, raised as many questions as it answered in my mind. I suppose
it will all be answered in the fullness of time...

Perhaps someone from IBM can fill in the missing pieces (hah!)

	-Barry Shein, Boston University