Tuesday, May 17, 2022

Introduction

This is a blog about old computer systems, constructing software emulators for them, and recovering such software for them as can still be found.

I have had an interesting and satisfying career with computer systems and software development, primarily with Burroughs mainframes and their Unisys successors, but over the past 20 years have found myself doing more and more web-based development. I was fascinated early on with the physically large machines and their fancy panels of lights and switches. As technology advanced and those attractive displays became both uneconomical and unnecessary for their original purpose -- system maintenance and operation -- I sort of missed that aspect of computing.

I had been thinking about the possibility of emulating some of the old machines I had used, and as I started to approach retirement, thought that might be an interesting activity to pursue. See this anecdote on one early influence that helped push me in that direction. Then a dozen or so years ago I met Nigel Williams of Hobart, Tasmania (Australia) on line. We had shared interests in computer history, software development, and Burroughs systems, and after a couple of years of discussion, decided to try to create an emulator for the legendary Burroughs B5500.

My thinking had been we might write the emulator in a language like Java or Python, but Nigel said no, we should write it in JavaScript so that it could run in a web browser. Even though by that time I had built a fair amount of experience developing web-based applications using HTML, CSS, and JavaScript, I thought that idea was crazy, but Nigel kept after me, and eventually convinced me that it was feasible.

So without much clue how to go about it, in 2012 we started designing an emulator for the B5500. After many adventures we had it beginning to work about a year later. We were fortunate that we got to ride the significant increase in web browser capabilities that started with the HTML5 standardization effort. We were also fortunate that at about that time JavaScript performance started to improve dramatically, a result of just-in-time compilation engines such as V8 for Google Chrome and WarpMonkey for Mozilla Firefox. In the end, both the B5500 emulation project and the web-based approach proved to be spectacular successes.

Working on the B5500 emulator was so gratifying and so much fun that I wanted to do more projects of that sort. I have now built three web-based emulators and found or recovered some amount of software for each of them:

Web-based emulators have become something of a specialty for me, and I am now working on a fourth one, for the Bendix G-15. This brings me to the rationale for this bog.

Shortly after starting the B5500 project, I thought it would be good to have a public record of the project's progress, so created a blog for it. Then when I started working on the 205, Tom Sawyer kindly allowed me to add posts to his blog devoted to that system. When I started the 220 project, Tom and I simply expanded the scope of his 205 blog to include the 220, which has a close relation to the 205.

Now with the G-15 project, I need a blog. It doesn't seem suitable to include information for that system in either of the other two blogs. Further, my experience with the other three emulators has been that there's a lot to write about for the first year or two of the project, but that tapers off as the functionality of the emulator becomes more complete and additional software for the system becomes more difficult to find.

Since I want to do more of these projects, and since a separate blog for each one doesn't seem justified, I've decided to keep the existing blogs as is for their respective projects and create one new blog to be used for all of my future emulation projects. I have been using the "retro" prefix as sort of a brand for all of these projects, hence this, the Retro Emulation blog.

In the near term, I will be writing about my work on the Bendix G-15 emulator and software, but I have a list of other systems which I am interested in researching and potentially building emulators. Comments and discussion on these projects and others' experience with the systems and software that will be covered here are most welcome.

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