From: storm@geog.utah.edu (John Storm)
Subject: Re: More on GIS Lab
Organization: DIGIT Lab
Date: Thu, 5 Nov 92 06:48:58 GMT

In article <9211042259.AA17058@gisjoh.noname>,         "(Robert Linton)" <rlinton@GISJOH.MUR.CSU.EDU.AU> writes:
|> Have you given any thought to running PC's networked back to a Sparc 10, and
|> using an X-Terminal emulation package such as MICRO-X or HCLEXCEED?
|> 

UGH!  I wouldn't recommend this solution to anyone.

Short Version:

We started off down this road, workstations and Xterminals, but found that
the performance hit you take is not worth the $$ saved.  Some of the problems
you can expect are heavy network traffic, syslog problems, management problems
(i.e... get good at SNMP and XDM quick), high load averages on the workstations,
etc...
It is much better to go with low end dataless workstations (i.e.. IPXs)
and one (or more) good workstation/server (i.e.. sparcII(or 10) with NFS cacheing
abilities).

Long Version:

Heavy network traffic & load averages =>

Arc/Info binaries do not adhere to straight X11 protocol, but rather make 
certain calls to proprietary Xwidgets and fonts that are endemic to your windowing
system of choice (Openwindows or OSF/Motif).  For example, the sun4c binaries
for openwindows will call for certain openlook-glyphs and need the openwin/libs.
I expect that the new rev6.1 sun4c binaries for Motif do the same (wanting the
Motif libs and fonts).  In regards to Openwindows, the problem is further
compounded by the fact that an Arc/Info display call starts a NeWS client rather
than a normal (bit mapped) X display client.  What this boils down to is that
even though you are sitting at a machine that emulates an Xstation, the window
manager will have to run on the workstation.  And the X emulation package has to
have the ability to run a NeWS client (for OLWM) which many don't.  This means
that for every Xevent (moving a mouse, etc...) network packets have got to fly.
Your workstation now has to handle all the CPU cycles, Xwindow-event updates, 
disk I/O, etc... for the PC xterm users, and your network has to handle all the 
traffic. I know of certain sites that have exceeded their bandwidth because of
this.  Xterminals are very chatty critters!

By running dataless IPXs the window manager, cpu cycles, and swap are all
local, thus a decreased netload and increased performance.  Would you
rather share a sparc10 with 10 other users all running windowmanagers and
Arc/Info sessions talking across the same wire, or have your own IPX?
We finally opted for the dataless IPXs, and dedicated sparcServers (w/
presto boards) for the undergrad. lab, but I can still tell when one 
of our Xterminals fires up!


syslog problems & management problems =>

There is too much about this to jam in here, all I can say is search the
archives of the sun-manager list for issues related to this topic - there
are many!  I would still advise you though to run xdm for the IPXs (whatevers)
it makes a very clean solution for logins.

|> Yet if you setup a network
|> of PCs, with all the necessary hard disk, tape and possibly CD-ROM storage on
|> the server, the network operating system, the network interface cards, and
|> anthing else that needs to make it fully functional, I wonder if the cost
|> would not approach the Sun workstation setup.  Even then you still have to
|> used software that is less powerful, less orientated to what students are
|> likely to encounter in the real world, and be tied to a 16 bit operating system
|> (at least until GIS software is available for OS/2 (maybe never) or Windows
|> NT (not even scheduled for release until sometime next year).


I think you are right on this $$!  The Windows NT version sounds promising
but from what I understoud it was for the new RISC based PCs that will
be released soon, I also heard through the vine that Windows NT is very
unstable -> so I think I'll not touch that one.  Your undergrads will
probably exceed the capabilities of PC Arc/Info, many here are pushing
the edge of workstation Arc/Info...  Better to let the PC's be Personal
Computers and get some NCs (networkable computers :-) ) you could probably
talk ESRI into letting you keep the PC Arc/Info licenses and turn them
into digitizing stations.

I also have to wonder about the new sparc10's - are they coming with
Solaris2.0 on them, or is it 4.1.2m.  Arc/Info will not be out for Solaris2.0
till next year, and 4.1.2m I heard does not optimize the MP arch.  For example
if you rip out 2 of the 4 processors on the 690's they'll run faster :-)
Anyone out there running on the sparc10's yet?

Before you do anything with Sun, hold out till they announce the new
"tsunami", soon!  Rumor has it they'll be about the price of IPXs but have
the CPU power of a sparcII.

Hope this helps?

     __________
    /         /	  DIGIT Lab		John Storm
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