Re: 10-Base-T and Pathworks

[Jeff Marraccini]

> 
> I got a chance to talk to some people at the Merit Tech. Staff meeting
> but I was wondering who else has experience with 10-Base-T and would be
> willing to answer a few questions (e.g. type of hubs used, problems
> encountered, etc.).
> 
> Also, on another note.  We are looking at DEC's Pathworks and from what
> we have seen, DEC really pushes VMS as the OS of choice when using
> Pathworks.  We have also read in some articles that DEC is looking
> toward phasing out VMS.  Does anyone feel that VMS will still be a
> strategic product for DEC in the future?  We would hate to purchase
> VMS today and have DEC in six months tell us that it is getting
> rid of VMS and we will have to switch to ULTRIX or something else
> instead of going with ULTRIX from the start.  Also, like the above
> question, who out there in MichNet-Land is using Pathworks and
> would like to give a few comments about it.

We have a large Pathworks installation here.  Most of our servers are
VMS-based, but due to several reasons (which I'll explain below) we're
moving towards Ultrix/Unix for file service purposes.

First, though: 10Base-T.  Our campus backbone uses Synoptics hubs.
About 10% of the active Pathworks nodes connect to the network via
10Base-T, including my own PC.  When the wiring is installed properly,
there are no problems.  Our 10Base-T plant has been much easier to
maintain than the thin-net plant, primarily because it's more
forgiving if someone leaves a cable unplugged, smashes a connector,
etc.  The concentrator just shuts off that port and an alarm is raised
on the management console if a serious error occurs.

Note that you will need to pick a wiring standard and STICK TO IT.
Don't let vendors enforce their wiring standards on you: find one that
has technical merit and ease of maintainability, and INSIST ON IT.
Otherwise, wire management becomes a real mess, particularly when you
start considering alternate services over the same wiring (IBM SNA,
RS-232/422, AppleTalk, etc.)  Sticking to one wiring standard also
lets you use different vendors connectors, wall plates, etc. with
confidence, since you always know exactly what type to order.

We use a mixture of Cabletron, Racal-Interlan, and SMC 10Base-T cards.
There's also a lot of DEPCA (the old ones) and Cabletron thin-net
cards.  All work quite well when they're configured correctly.
Pathworks supports most boards that have good NDIS driver support
(although be aware that not all NDIS drivers are created equally.  Ask
the vendor before buying if their NDIS driver has been tested with
Pathworks for DOS 4.0 or above, or if they have native DLL support for
Pathworks.  Most of the big companies do, or at least have good NDIS support.)

Now, back to Pathworks:

For the moment, Pathworks for VMS supports the most services.
Pathworks for Ultrix doesn't support virtual disks (essentially a
large file on the file server that mimics a DOS floppy or hard disk.)
This facility is required for remote booting a PC off of the file
server using a DEPCA card.  Thus, you cannot use a Pathworks for
Ultrix server to support remote-booting PC's.  This may or may not be
a problem.  For us, since we've found that remote boot is nice for
some of our older PC's, it means that we have to maintain at least one
Pathworks for VMS server.

Both servers (VMS and Ultrix) support electronic mail using the
supplied PC client program, DECwindows (although this seems to work
better under Ultrix, since there are more interesting X/DECwindows
programs available for Ultrix.)  Printing to Ultrix and VMS print
queues work very well.  You need to be very careful with the printcap
entries on an Ultrix system, though: there are some entries that are
not supported via Pathworks.  I can't give much detail on this yet,
since I basically did a plug-n-play installation.  There are example
printcap entries in the installation manual that work fine.

Both servers require about 5-10MB to operate correctly.  They can both
log usage activity in a rudimentary way as well as server errors.
Both have a full-screen, menu-driven management interface.  Most
maintanence tasks require access to the root account: creating a copy
of the pcsamgr program with the setuid bit set and limited group
access does NOT work in my experience.  Under VMS, the administrator
requires some privileges, but limited administration is possible with
only the OPER privilege.

Now, to my own feelings on VMS:

DEC doesn't seem to be dropping VMS, although the product is changing
(for better or for worse, I don't know, since my own interest in VMS
waned about 3 years ago.)  However, support for Ultrix and now OSF/1
is building up rapidly.  The Pathworks for Ultrix product has become a
lot more stable, to the point that we're in the process of moving the
majority of our Pathworks services to it.  Even on the same hardware,
we've had modest performance increases by using Pathworks for Ultrix,
especially under heavy loads.

A lot of this speed increase appears to be due to the Ultrix file system and
the differences in file system caching, but I suppose the improvement
(or lack thereof) would depend on your applications and how the
servers are configured.  Our servers tend to have minimal memory (most
have 8MB) and except when another primary file server is down, support
no more than 50 simultaneous users.

Since I'm the primary Pathworks administrator here, and I'm much more
comfortable with Unix, I'm pleased that the Pathworks server has come
of age under Ultrix.  The loss of virtual disks means that I can't use
the Ultrix servers to support remote-booting computers, but the gains
that we're experiencing by starting to move the file servers to Ultrix
have more than outweighed this.  Administration has been far easier
for me, and the users seem to like the ease of handling their files
under Ultrix.  VMS was a confusing environment for PC users: the
directory structures were plain weird from a PC point of view, and
even though the security (ACL's) was superior to what an Ultrix system
can do, maintaining them and understanding how to set them up from a
PC was tedious.

One last Ultrix benefit that you might want to consider is:  if you
have services that you want to offer to PCs that are on other types of
systems, such as Suns, HP's, etc. remember that Pathworks for Ultrix
can handle NFS file systems fine.  You might need to check with DEC if
you have an application that requires file locking on a remote NFS
file system, though.

Jeff

-- 
Jeff Marraccini                              jeff@vela.acs.oakland.edu <- Work
Computing Resource Administrator             jeff@nucleus.mi.org       <- Home
Oakland University                           +1 313 370-4542
Rochester, MI USA 48309-4401        "The Computer is your Friend." -- Paranoia
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