Simple Systems Exhibiting Self-Directed Replication:
Transition Functions, Software, and Documentation
March, 1993
We have recently developed and studied cellular automata models of
self-replicating systems [Science, 259, 1993, pp. 1282-1288].
Files containing a version of the various transition functions
and software that we used in this study, as well as documentation,
are now available via ftp. The cellular automata software is actually
fairly general and could also serve as an application-independent
simulator. For further details please refer to the paper cited above.
Here is a brief description of how to get this online information:
1. If your system is not on Internet we cannot help. You might
ask your friends on Internet to get this material for you.
2. If you are on Internet, type
ftp ftp.cs.umd.edu
if this does not work, type
ftp 128.8.128.8
You will see the following message
Connected to 128.8.128.8.
220 mimsy.cs.umd.edu FTP server (Version 4.135 Thu Apr 26...
Name (128.8.128.8:hhchou):
Now type in the login name "anonymous", then type in your email id
as the password. You will see the following prompt
Name (128.8.128.8:hhchou): anonymous
331 Guest login ok, send ident as password.
Password:
230 Guest login ok, access restrictions apply.
ftp>
3. Type the following command to change directory to /pub
cd pub
Next type the following command to signify binary file transfer
bi
You will see the following message
ftp> cd pub
250 CWD command successful.
ftp> bi
200 Type set to I.
ftp>
4. Next, type the following command to get the files.
get dtr.tar.Z
You will see something like this
ftp> get dtr.tar.Z
200 PORT command successful.
150 Opening data connection for dtr.tar.Z (128.8.128.151,...
226 Transfer complete.
local: dtr.tar.Z remote: dtr.tar.Z
1598529 bytes received in 49 seconds (32 Kbytes/s)
ftp>
Type the following command to quit ftp
quit
5. After you have transferred the files, move them somewhere in your
system where you want to store them. Finally, type
zcat dtr.tar.Z | tar xvf -
This will retrieve everything in this package, and give you a
directory called "dtr". Follow the instructions in the README file
there.
We hope you find this package useful to you. Note that although care
has been taken while preparing this package, we know bugs are there
somewhere. We do not have the resources to provide maintenance and
support for this software. Suggestions or bug reports are welcome.
If time permits we will try to fix any bug found and provide an improved
version in the future. We would appreciate it if you acknowledge the
use of this software in any future research reports that you might
base upon it and send us a copy of such reports.
Please send your correspondence to:
hhchou at eng.umd.edu.
Hui-Hsien Chou
Dept. of Computer Science
A.V. Williams Bldg.
University of Maryland at College Park
College Park, MD 20742 USA
