Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!math.lsa.umich.edu!emv
From: davea@vlsi.ll.mit.edu (Dave Allen)
Newsgroups: comp.archives
Subject: [rec.games.frp...] Continental Drift Simulator
Message-ID: <11135@stag.math.lsa.umich.edu>
Date: 23 Feb 90 23:57:30 GMT
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Reply-To: davea@vlsi.ll.mit.edu (Dave Allen)
Followup-To: rec.games.frp,rec.games.programmer,comp.sys.amiga,comp.sys.ibm.pc
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Approved: emv@math.lsa.umich.edu (Edward Vielmetti)

Archive-name: latex-fancyheadings/22-Feb-90
Original-posting-by: davea@vlsi.ll.mit.edu (Dave Allen)
Original-subject: Continental Drift Simulator
Archive-site: sol.cs.ruu.nl [131.211.80.5]
Archive-directory: pub/TEX/latexstyle
Archive-files: fancyheadings.*
Reposted-by: emv@math.lsa.umich.edu (Edward Vielmetti)


Last week, I wrote that I had released a new version of my continental
drift simulator.  I posted it to comp.sources.misc, and many people wrote
to me with questions.  Here are some common answers:

If you don't know what comp.sources.misc is, it's a usenet news group
just like rec.games.frp.  Use your news reader to subscribe to this group,
or ask a local expert.

If you were unable to locate the programs on comp.sources.misc the
first couple of days after I posted the announcement, please look
again.  I posted the announcement and the source at the same time, but
programs take a few days to clear the c.s.m moderator.  The archive
numbers are v10i077 and v10i078.

You can get the source code by ftp.  Several sites archive comp.sources.misc.
For example, I looked at uunet.uu.net, and found the program in the directory
comp.sources.misc/volume10/tec, with the filenames part01.Z and part02.Z.
Ask a local expert for help in finding a local archive site or using ftp.

Several people have written to me that the IBM PC version fails with a
message "PANIC: infinite loop in pfree".  This message implies that the
linked list of plates is getting munged.  Most people see the problem within
a small number of iterations, like two or three, and it shows up every time
they run the program.  I can run the Sun version 100 times for 100 iterations
each and never see the message.  I would like some help in tracking down this
machine-dependent bug.  Here is a clue provided by one reader:

From: Jeff Butterworth <butterwo@cs.unc.edu>
> Eventually I tried fiddling with the compiler options again, and found that
> setting the default character type to "unsigned" did the trick.  The program
> runs now, but it seems to be creating initial continents that are quite
> squarish, unlike the ones I saw when leaving default characters as "signed".
> Maybe some random number generator is now being messed up because it assumes
> that characters are signed.

Since I have no access to a PC here, I can't look for the bug.  However,
I would like to help somebody track it down and squish it.  Please write to
me and I will answer any questions you have about the code.

Please e-mail me directly rather than posting, since I don't read
all the groups where this message is going.

Dave Allen: internet davea@vlsi.ll.mit.edu