🚀 go-pugleaf

I thought I might toss in some replies to Klaus Kusche's opinions.

> About the QBUS: ...Parsytec will have one (for Parsytec boards only).
> ... I don't know about Ultrix.

We've been using the Parsytec QBUS board with a MicroVAX running Ultrix for
our Helios work.  We've done a port of the Helios Server program so that
you can access Helios from the VAX and also through sockets so that programs
can use the transputers as a resource.  This is not an official product as 
yet, but we expect that it will become available soon.

> About Parsytec: ...why do they refuse to be compatible with the rest 
> of the transputer world? I have the feeling that they just want to force 
> you to buy their software: Their hardware is just different enough from the
> rest of the world that Inmos-compatible software will not run unchanged,
> but can be adapted with a few bytes patch (just Parsytec knows how).
> Also, their software releases are usually back a little bit for that
> reason...

We have a few Parsytec boards in house and have not had any software
compatibility problems at all.  We only run Helios, but its not a special
copy of Helios from Parsytec or anything.  One possible reason for their
lack of compatibility is that I think Parsytec is looking beyond the P.C.
add-in market.  They are striving to become (and are becoming) a super-
computer company.  I suspect that in a large system (64 to 256 nodes and 
beyond) things like differential links become relevant.  It also becomes
very useful to be able to reset an individual transputer, particularly
in multiple user configurations.  

All of the Parsytec boards that we have, including the QBUS board, have
some provision to get at least one link to be Inmos compatible.  We currently
have a system in-house that uses the Parsytec QBUS board on the MicroVAX
which is connected to a series of MicroWay boards in another chassis.  The 
transputers are running Helios and the MicroVAX is running Ultrix.  We got 
this configuration running after considerable work getting the Parsytec 
board's links to interface to the MicroWay links (which are standard), but 
in the end it was a documentation failure -- they just hadn't documented all 
there was to know about getting the links to run Inmos style, and our engineer
was curious enough to wonder why a set of resistors were socketed.

> About MicroWay:
> You get what you pay for, and the MicroWay boards are rather cheap...
> There are definitely PC board companies which I would trust more with
> respect to quality.

We are also running on MicroWay boards and have had no trouble whatsoever.  In
fact, one of our engineers has said that on an oscilloscope the link signals
are much cleaner than some of the other boards he's seen.

> However, Helios should run on them [the Microway boards].

It does.

> About GNU C:
> Has been done as an academic project as far as I know, but is not (yet)
> available to the public.

Who's doing this?  Late last year I inquired about GNU C and didn't find
anyone doing it.  The main stumbling block is that GNU C's code generation
is for register based machines.

> PC-based transputer systems are an open market. Anything else will
> most likely restrict your future hardware and software choice to a
> single company, and will cost more (however, if you like Unix, have
> *a lot* of money, want a highly sophisticated programming environment,
> and know for sure that you will never need any software except the one
> offered for that particular system, you should probably consider Meiko's
> Sun solutions or something similar).

A cheap(er) trick is to use a Sun 386i, which has a PC bus.  This gives
you UNIX and the networking environment without the extra price.  The risk
here is whether Sun will continue to support anything that doesn't have a 
SPARC chip in it.

I agree that you should evaluate how well the various vendors interconnect,
perhaps the group on the net could help fill out that matrix.  I'll be happy
to collect responses on that and to report the results to the net.  Our view 
has been that as long as we can get a single transputer board for the 
particular bus, we can run links out to a PC chassis with a passive backplane 
full of 'puters.  We have only tested this philosophy out with the above 
mentioned system...so at N = 1, our theory stands.  But it seems that the 
transputer is so highly integrated that its really a pain in the neck to 
make the thing incompatible with other systems.  

Steven W. Engle
MIMD Systems, Inc.