Welcome to the Datatron 205 and 220 Blog

This blog is a companion to T J Sawyer's Web Page that outlines the history of the Burroughs Datatron 205 and Paul Kimpel's incredible 205 and 220 emulators. Please visit those sites and return here to post any comments.

Friday, February 6, 2015

Burroughs 205 Emulation - A Personal Story

When I left the University of Portland in 1967 in my '56 Dodge and headed for graduate school in Minneapolis, I packed all of my essential items: Peter, Paul & Mary albums, Beach Boys albums, a good vacuum tube amplifier and turntable and most of my math books.  And, oh yes, a listing of the Burroughs 205 Algol compiler on 11x13 fan-fold paper.

I suppose it is some measure of change over 48 years that "fan-fold" doesn't even have its own entry on Wikipedia.

I've lost track of the number of different places that listing has been stored - but it has been carefully preserved.  I always intended to write a 205 emulator "when I had the time."  The time must have made itself available in the early 1990s since I wrote my first version in VisualBasic.  I wrote a few machine language programs and got those running on the emulator to prove out the machine.

I patiently did a manual transcription of the Algol listing and gave it a shot.  Between my transcription errors and a few emulation errors, it took quite a while before I had my first program compiled.  I started out with just enough instructions implemented to run my machine language square root program.  I would then try to run the compiler and when it used an additional instruction, I would implement that one next.  You could call it a "minimalist" method of implementation.

I set the project aside for several years.  When we first began to spend full winters in Egypt, in early 2009, I decided to re-implement in a more modern language.  I chose JAVA and over the course of the first winter here I got that version running, albeit still incomplete.

But, I did get a number of basic Algol 58 programs to compile on this version.  Much of the work involved struggling with the Algol syntax and special characters that were used on the old Burroughs to represent parentheses and the like.  (I didn't have an Algol 58 manual with me and there were no clues available on the Internet.)

So the news last December from Paul Kimpel last summer that he was planning to construct a "real" B205 emulator was very exciting.  Seeing the product begin to take form with its realistic looking control panels was fascinating.

Congratulations to Paul for having the patience and perseverance to take on this job for what is likely a small audience. 

No comments: