announce.40

地球模拟器

                         TIERRA UPDATE
		     V4.0, September 1992:

This message contains:

1) Availability of Tierra V4.0 Source Code
   a) by ftp
   b) by snail mail on disk
2) Bug Fixes
3) Three New Instruction Sets Implemented
4) New Memory Allocator Installed by Chris Stephenson of IBM
5) Full Memory Protection Implemented
6) Virtual Debugger Enhanced
7) Diversity Tool Enhanced
8) Tierra Display Color Mapping
9) Alive Variable Changed
10) CM5 Port
11) Future Phylogeny
12) Tierra in the News
13) Tierra Publications
14) Mailing Lists
15) What Tierra Is (If you don't know what Tierra is, read this first)

1) Availability of Tierra V4.0 Source Code

     The Tierra V4.0 source code; and the source code, and DOS executables of
all tools is available now.  Please note that the source code in the ftp
site and the source code provided on disk will each compile and run on either
DOS or UNIX platforms.  It is exactly the same source code in either case.
The DOS executables are available only on disk, and can not be freely
distributed.

     If you purchase this program on disk, thank you for your support.
If you obtain the source code through the net or friends, we invite you to
contribute an amount that represents the program's worth to you.  You may
make a check in US dollars payable to Virtual Life, and mail the check to
one of the two addresses listed below.

   a) by ftp

     If you use the software, be sure to pick up new versions from the ftp
site.  The source in the ftp site will be replaced on a roughly monthly or
bi-monthly basis.

     The complete source code and documentation (but not executables) is
available by anonymous ftp at:

tierra.slhs.udel.edu [128.175.41.34] and
  life.slhs.udel.edu [128.175.41.33]

in the directories: almond/, beagle/, doc/, and tierra/.

To get it, ftp to tierra or life, log in as user "anonymous" and give your
email address (eg. [e-mail]) as a password.  Be sure to transfer binaries
in binary mode (it is safe to transfer everything in binary mode).
Each directory contains a compressed tar file (filename.tar.Z) and a SRC
directory that contains all the files in raw ascii format.  You can just
pick up the .tar.Z files, and they will expand into the complete directory
structure with the following commands (Unix only):

uncompress tierra.tar.Z
tar oxvf tierra.tar

   b) by snail mail on disk

     The source code, documentation and the beagle.exe file can be distributed
freely, however, the executables (the .exe files in DOS) are for sale and
cannot be freely distributed (with the exeception of beagle.exe).

     If you do not have ftp access you may obtain everything on DOS disks
by making a check for $65 (US dollars drawn on a US bank) payable to
Virtual Life.  $20 for upgrade from earlier version (please specify your
serial number and version number).  Specify 3.5" or 5.25" disks.  Send the
check to one of the following addresses:

Tom Ray                  (January through August)
Santa Fe Institute
1660 Old Pecos Trail
Suite A
Santa Fe, NM 87501

Virtual Life             (September through December)
P.O. Box 625
Newark, Delaware 19715

     The DOS disks contain everything but ALmond (ALmond can be provided on
disk by request, but it only runs on a Unix platform).  The disks include DOS
executables, source code and documentation.  The DOS disks include an easy
installation program.  This is the same source code available in the ftp
site.  If you have ftp access, there is no need to buy the disks.

2) Bug Fixes

new in V4.0:

call(), jmp(), jmpb() - for each of these instructions, if there was no
     template following the instruction, the instruction pointer failed
     to increment, so the cpu would hang on the instruction.  This has
     been fixed in V4.0.

moviab() - (renamed to movii) this instruction looks to see if the target
     address is not in the daughter cell, in which case it calls MutBookeep()
     to keep track of genetic changes caused in the target creature.  Before
     V4.0, it did not look at changes to the byte following the daughter cell,
     this has been fixed.

break files - previous to V4.0, if the Tierra program was terminated by a
     system crash, or by the Q command, it would not be possible to fully
     recover by restarting the simulator.  The reason was that when restarted,
     the simulator would start the clock from the last system save, but would
     append birth death records to the end of the break.X files.  This meant
     that the part of the break files produced after the crash would be
     invalid.  This has been corrected in V4.0 by saving the file position
     pointer in the soup_out file.

diverse - in earlier releases, there was a bias in the calculation of the
     average age of the genotypes towards higher values.  This has been
     corrected, and it is believed that all of the statistics put out by
     this tool are now valid.

new in V3.13:

adr() - the parse function for the adr instruction, previous to V3.13, set
     is.iip = 0, which meant that the instruction pointer would not increment.
     This means that if ever the adr instruction were executed, the virtual
     cpu would hang on this instruction.  This has been fixed in V3.13.

GarbageCollectGB() - previous to V3.13, this function (in bookeep.c) caused
     some empty .gen files to be created, which would clutter up the genebank
     directory.  This has been fixed.

genotype histogram - there were some problems with the genotype histogram
     display in V3.12, these have been fixed.

3) Three New Instruction Sets Implemented

     The Tierra simulator now comes with four complete instruction sets,
the original and three new ones.  The three new sets came out of a series
of meetings held by the Tierra group at the Santa Fe Institute over the
summer.  These meetings were attended by Tom Ray, Dan Pirone, Kurt Thearling,
Chris Stephenson and Walter Tackett.  The new instruction sets are designed
to be more suitable for general purpose computation.  They overcome some of
the obvious weaknesses of the original set.  Specifically, they allow for
movement of data between the soup and the cpu registers, and they provide
I/O services.  In addition, they include some important biological features.
Specifically, they provide facilites for inter-cellular communication.  They
also allow for the transmittal of non-genetic information between mother
and daughter, and they allow the mother cell to force the daughter cell to
differentiate, by controlling where the instruction pointer starts in the
daughter cell.

4) New Memory Allocator Installed by Chris Stephenson of IBM

Chris Stephenson of the IBM T. J. Watson Research Center
([e-mail]) has contributed a new memory allocator to Tierra,
based on a cartesian tree scheme that he developed.  The new allocator is
more efficient than the old and provides a variety of options for controlling
where offspring are placed.  Free blocks are maintained in a two dimensional
binary tree, in which daughter blocks can not be larger than their parents,
and blocks are ordered from left to right according to their position in
memory.  The options are provided through the soup_in variable MalMode:

MalMode = 1 0 = first fit, 1 = better fit, 2 = random preference,
# 3 = near mother's address, 4 = near dx address, 5 = near top of stack address

5) Full Memory Protection Implemented

     The memory protection options used to create the "cell membranes"
around creatures now allow full read, write or execute protection.  The
two forms of protection, with and without membranes, are controlled by
two soup_in variables.

6) Virtual Debugger Enhanced

     The virtual debugger has been enhanced by a tracking feature which
will allow you to either follow exclusively the execution of a single cell,
or to swap between execution of cells as the slicer swaps.

7) Diversity Tool Enhanced

     The diversity tool has been enhanced in two way.  It optionally
calculates an average of each of the diversity indicies, over a user defined
interval, and outputs only the cumulative averages at the end of each
interval.  Otherwise it may output the diversity indices after each birth
and death.  Outputting only the averages greatly reduces the volume of output.
The other enhancement is a frequency filter which allows the diversity
indices to be calculated on the basis of only size or genotype classes with
at least some user defined number of individuals.  The default is two
individuals.  This means that the calculations will not include the numerous
mutants of which there are only a single individual.  This prevents the
diversity indices from being dominated by the large number of inviable
mutants that always exist in the populations.

8) Tierra Display Color Mapping

     In order to facilitate the needs of a user running Tierra on an LCD
display, the mapping of colors in the Tierra standard display are now
configurable by means of an ascii file called tcolors.cfg.

9) Alive Variable Changed

     The alive soup_in variable that controls the length of a run now
counts generations rather than millions of cpu cycles.  This has been done
to provide a control that is more comparable across instruction sets.

10) CM5 Port

     Kurt Thearling of Thinking Machines Corp. is working on a port of
Tierra to the new CM5.  This will be a true MIMD port: some processors will
run the simulator while other processors will run the genebanker.  The port
is based on an archipelago model, in which each Tierra processor will run
a compete Tierra soup.  However, creatures will be able to migrate between
processors through the dispersal of offspring.