CHRIS@ENGVAX.UUCP.UUCP (02/24/87)
[bug poison]
After searching long and hard for a product to connect an IBM to VAXs
running VMS, when the VAXs are already hooked to each other using DECnet and
TCP/IP over ethernet, I came up with four four basic solutions. These basic
solutions are as follows:
1) A product that turns a VAX into a HASP/RJE station from the IBM's point of
view.
2) A product that "gateways" between DECnet in the DEC world and SNA in the
IBM world.
3) A product that teaches the IBM to speak TCP/IP.
4) A product that teaches the IBM to speak DECnet.
Solution #1 was already in place when we started the search for a faster,
easier, and hopefully more functional solution. We *REQUIRED* the ability to
submit jobs from the VAX to the IBM, to be able to transfer files back and
forth. We were also hoping to hit random print queues on the IBM in a simple
way also. We had a 9600 baud link to the IBM, and our engineers were having
problems transferring 40K block files (these are "small!!!!!" to our IBM people)
in less than 4 hours. This solution required that JCL be built to transfer
files and print things on the IBM. It also didn't allow for the IBM to
initiate file transfers in a really clean manner.
Solution #2 is the one that DEC would have you purchase. Now you *need* a
controller on the IBM with some free ports (the 9600 baud ports were the fastest
that we could get), and even with the free ports, max speed was 2 lines running
at 56 KB. Your IBM also has to be talking SNA. The real kicker is that EVERY
VAX THAT WANTS TO TALK TO THE IBM NEEDS TO HAVE SOFTWARE ON IT!!!! Sure, you
don't need any software on the IBM, but if you have a DECnetwork with more than
10 nodes that want to talk to the IBM, the software costs become prohibitive.
Solution #3, the TCP/IP solution, is OK. Fiberonics (Sparticus) has a box
that is bus and tag connected to the IBM, the software is nicely centralized on
the IBM, and it becomes a node in your TCP/IP network. This requires that you
run out and buy TCP/IP for your VAX, but we already had that. It also allows
your Unix machines, and whatever else speaks TCP/IP to talk to the IBM easily.
This is by far the closest to a "universal" networking scheme of any, and if
you're not mainly interested in interfacing IBM and DECnet machines it's
probably the way to go. As far as I was able to tell, you have two basic ways
to talk to the IBM, you could send files back and forth (ftp), or you can log
into the IBM (telnet). This did not provide enough functionality for our
users, we needed the ability to submit batch jobs onto the IBM quickly and
easily, sometimes from a batch job on the VAX.
Solution #4, the DECnet solution, is what we ended up with. Interlink
makes a box that is bus and tag connected to the IBM, it's software lives on
the IBM, and it's a (unfortunately routing) node in your DECnetwork. This
means that any DEC product or Sun with DECnet can talk to the IBM with no
additional software. Our Unix machines can gateway over to the IBM through any
of our VMS machines, since they speak both TCP/IP and DECnet. Jobs are easily
submited from the VAX to the IBM, and from the IBM to the VAX. Any printer on
the IBM is reachable, if you have a VM IBM with Profs mail, you can send mail
back and forth between the VAXs and the IBMs. The really fun thing is that
from the VAX you can edit files on the IBM! (He he, now I've started editor
wars!) The Interlink hardware consists of a PDP (speed and size depends on the
amount of $ that you pay them) and an AUSCOM network controller. We have the
full blown $100K solution that runs at speed up to 400 KB (8600 w/ DEUNA
interface on the VAX end, locally clocked), though (last I checked) they have a
$25K solution that has been clocked at 100 KB. Best of all, any of the DECnet
nodes out there on the corporate DECnet (including a couple of other IBMs with
Interlink boxes...) can have access to the IBM just by defining them in the
Interlink's DECnet database. The product is available for both MVS and VM
systems.
We haven't had the Interlink for too long, but the two other sites in the
company are reporting good things. We've had some problems (now more or less
ironed out) with the ACF2 privilege level that the software on the IBM wanted
to run at (if you want more detail, I'll bore you with that in private) and
with attempting to define node numbers higher than 782 in any given DECnet area
(we need all 1024, or actually the first 999 of that...). Functionally the box
has worked in every way promised, and our users are more than pleased.
-- Chris Yoder UUCP -- {allegra or ihnp4}!scgvaxd!engvax!chris
Hughes Aircraft Company ARPA -- chris%engvax.uucp@usc-oberon.usc.edu
Disclaimer: I do not get commissions (monetary or otherwise) from *anybody* for
the sale of IBM <-> VAX communications. I am just a (more or less) satisfied
customer of Interlink. GM and Hughes do not take any responsibility for
anything that I may babble to this forum.