1 class

Introduction to Systems Modeling and STELLA

Course Logistics
Three step modeling process
Based on the Leaky Bucket Model found in Haefner (1997), we examine Stella and the two modeling approaches: mechanistic and empirical. You can download the MAC (40 K, stuffed and binhexed) or DOS (40.4 K, pkziped and uuencoded) versions of the two models built.
Modeling for consensus building

STELLA disk images. Please do not forget to remove them from your computer at the end of the course.

MAC (all files, compressed and binhexed 6Mb)

DOWNLOAD Disk 1 (1.45 Mb).
DOWNLOAD Disk 2 (1.46 Mb).
DOWNLOAD Disk 3 (1.46 Mb).
DOWNLOAD Disk 4 (0.36 Mb).

PC (all disk images, zipped and uuencoded 6.7Mb)
If you have problems unzipping or working with disk images, try to download the individual diskettes. Save Disk 1 as setup.exe, then save the other 3 disks in the same directory, calling them setup.w02 setup.w03 and setup.w04, respectively. In some cases the browser will display the disk images as text. You would then need to do "Save As" and save the file directly from the browser page. Now run setup.exe from that directory. It should find the other files by itself. In some cases you might need to put the files on floppies if the setup asks for Disk 2,3,4.

DOWNLOAD Disk 1 (1.47 Mb).
DOWNLOAD Disk 2 (1.47 Mb).
DOWNLOAD Disk 3 (1.47 Mb).
DOWNLOAD Disk 4 (1.47 Mb).

Exercise 1

Exercise 1 is a simple one-variable model that you can investigate, analyze, play with. This should help you build a one-variable model of your own by next time we meet.

DOWNLOAD a Mac version (16.5 K, stuffed and binhexed).

DOWNLOAD a DOS version (16.7 K, pkziped and uuencoded).
If you do not know (and do not want to know) how pkzip and uudecode work, try to download the plain binaries for the Exercise 1 model .

Note

If anybody has trouble with unzipping and uudecoding, the latest version of WinZIP (version 6.2) has UUencode capabilities. Can be downloaded from http://www.winzip.com

FAQ for Stella downloads

Q: I have been having trouble downloading stella. It keeps coming up as a text document instead of an executable file.

A: This is probably because of how your browser is set up. If the file opens as text in the browser window you can still try to save it using the "Save As" option from the File menu. Make sure you choose the "Source" option when doing that. Alternatively instead of clicking on the Download button you can hold down the mouse and when a menu appears choose the "Save This Link As" option.

Q: The first thing I tried was downloading the images. I got them uudecoded and unzipped, but now I just have four *.img files that Windows doesn't seem to recognize.

A: As a Mac person I cannot be entirely sure about how Windows handles the images. On a Mac computer this is quite standard: you simply "mount" the image and it appears on the desktop as if the floppy was in the drive. You can mount all the disks and then when running Setup it simply finds them when it needs them. I found out that there are similar programs for Windows machines which do this (rawrite.exe). Check out http://uranus.it.swin.edu.au/~jn/linux/rawwrite.htm. Another place where you may find the software needed is http://www.winimage.com There are also some freeware and shareware programs for handling disk images available at http://download.cnet.com/, however I did not have a chance to test them.

Q: Unfortunately, I can not download the exercise 1 to my PC computer. Can you help me with that?

A: This is just as an example of a request that there is no way we can handle. If there is a problem, please describe what have you been doing and were did you get stuck.

Click here to Upload your models
Please use your name as part of the uploaded file name. For example, if John Smith is uploading his model for debug exercise 3, he would call it smithj3.stm
Do not worry if the file you uploaded does not appear on the directory listing - I've made this a write-only directory. So once the file is there, it's there - you should not be able to get it back.

If you wish to receive info about updates on the web page and news about the course, please send your e-mail address to Alexey Voinov. Also let me know if you have any problems downloading and running the models.