[extropy-chat] Re: SPACE: where are we?

Robert J. Bradbury bradbury at aeiveos.com
Mon Feb 9 19:11:42 UTC 2004


On Sun, 8 Feb 2004, Mike Lorrey wrote:

> --- Rik van Riel <riel at surriel.com> wrote:
> > On Sat, 7 Feb 2004, Robert J. Bradbury wrote:
> >
> > > One has to wonder what open source development of the Mars Rover
> > > software might have been capable of?
> >
> > While I am a very big open source proponent myself,
> > it will be worth realising that in this case it
> > probably wouldn't have helped much, if any.
> >
> > For one, only NASA seems to have the hardware to
> > run these programs on, so there won't be many home
> > users reporting bugs and sending in patches...
>
> Yes, this is a point. It also seems that this computer system is common
> to quite a number of NASA probes.

I'm not sure of the extent to which Rik and Mike are
agreeing with me or disagreeing with me.

But if you are disagreeing it ain't gonna cut the mustard.

In the first place to the best of my ability to determine thus
far the NASA probes (as well as many others) are running a
RAD hardened version of IBM processors that were common in the
early-to-mid '90s.  One would assume you can pick these up
(in the non-RAD hardened form) on eBay for pennies on the dollar.

Now, in the second place you are speaking to someone who helped
to write a PDP-10 simulator that ran on a PDP-11 (simulating a
mainframe on a minicomputer for those not versed in computer lore).
The software was actually used to recompile the Digital Equipment
Corporation PDP-11 Fortran Compiler which was written in Bliss-11 (the
compiler for which under normal circumstances only ran on PDP-10's).
I would have to think about it a bit but I think the recompilation
of the compiler may have taken longer (perhaps 1-2 months) than
writing and debugging the simulator took.

So there is no way in hell that you are going to convince me that
"only NASA seems to have the hardware" is an argument that is
going to cut the cake.

Except in the actual application (and Hello -- you have to be
in space where the RAD capability is a strong consideration) the
hardware doesn't friggen matter to the software.  If I don't have
the hardware I can simulate it.

Robert





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