4.3.3.4 Adaptability for Microworlds
The predominant reason for the choice of BLOX for the TODOR project was the need
to make the software easier to use. But its adaptability helped TODOR survive
over the course of a number of years in the Athena environment, while other key
projects were unable to be maintained due to changes in the environment.
This is described in the passage below by LaVin (personal interview, October 2, 1992),
coordinator for the project:
LaVin: When the project started, the world was still using
X-Windows System version 10. Athena didn't consist of networked workstations.
It was a bunch of time sharing machines with a few X terminals in a couple
of the clusters. TODOR was written in a third party toolkit called BLOX.
It's not a very big product. It's from a local company called Ruble Software.
It was a development environment that let you define what the flow of the
program would be through a series of text files. There was a menu table
and a state table. They were all flat ASCII text that you would compile.
You would use the tables to tell BLOX what FORTRAN routines went with a
given button in the menus. It was the only thing that existed at the time,
and it was invaluable. Basically, we're one of the only projects that still
has software running the way it was developed in 1985. We were saved from
having to deal with the changes in the X-Windows System. When we switched
from X-Windows System Version 10 to X-Windows System Version 11, the device
drivers changed, so all of our codes just needed to be recompiled. We didn't
realize that this was going to be one of the advantages of using this software.
According to Kinnicutt (personal interview, October 1, 1992) it is wise
to consider the issues of adaptability before creating the courseware,
particularly in distributed environments, where standards and formats
sometimes change:
Kinnicutt: I've been here since 1985, and over that time,
I've seen Athena change. Sometimes we have to go back and rewrite some
code which becomes obsolete. Initially, the project started using
X-Windows System Version 10, and a programming library called X Objects,
which was developed here. When we changed to XWindows Version 11, all
the X Objects code became obsolete, and Nomad had to be almost entirely
rewritten using X-Windows System Version 11 and Motif. Recently Athena
has been phasing out the RTs and VAXstations, and replacing them with
DEC 5000 color workstations as the base. The switch has gotten quite
a few developers really busy porting their code. Initially, when I
started writing my own code, I wasn't really thinking about portability
issues. Over the time, that's changed drastically. Now, I try to make
the extra effort to make sure that my code is portable the first time.