From time to time I wonder regardless of whether I’m the only a person who has pastime assignments that drag on for yrs, shifting back and forth amongst the metaphorical again-burner and front-burner of my notice span, evolving and transmogrifying as the months turn into months and the months flip into years and—in the case of some of my creations—the a long time transform into decades.
These types of has proved to be the case with my Heath Robinson Rube Goldberg (HRRG) pc, which was at first supposed to be an 8-little bit device when it was initial conceived deep in the mists of time.
This bodacious magnificence is named in honor of British cartoonist and illustrator William Heath Robinson (1872-1944) and his American counterpart Reuben Lucius Goldberg (1883-1970). Both equally of these gentlemen were being famed for generating illustrations of cunning contraptions whose goals have been to execute seemingly simple duties, but whose realizations done explained tasks in exceedingly convoluted strategies.
This all began when I observed a relay-based computer system produced by Professor Harry Porter III, who was a lecturer at Portland Condition University at that time (he could continue to be there for all I know). (You can learn much more about Harry’s device here.) I liked the seem of the relays clicking, and I also liked the way Harry presented his equipment in a series of glass-fronted, wall-mounted picket cabinets. On the other hand, I wasn’t so keen on the bundles of wires linking the cabinets together.
To be straightforward, I’d experienced the thought of setting up a relay laptop or computer lurking in the back again of my thoughts for some time. I’d even absent so considerably as to buy some secondhand books on generating relay-based mostly logic relationship from the 1950s and 1960s. The dilemma was that, in addition to inspiring me, Harry’s development also dampened my spirits for the reason that I did not want to do a thing that a person else experienced presently done, if you know what I imply.
This is what led me to my primary superior-stage notion of the HRRG Pc, which was to create my equipment as a series of glass-fronted, wall-mounted wood cupboards, like Harry’s, but with every of my cupboards made up of a portion of the laptop understood in a different implementation technologies, together with (but not confined to) relays, vacuum tubes, discrete transistors, jelly-bean (7400-sequence) built-in circuits (ICs), mechanical logic, magnetic logic, pneumatic logic…to title but a several. Also, in preserving with the HRRG philosophy, we would do away with the bundles of cables, employing any inter-cabinet communications through a wireless mesh community.
I really place a considerable total of thought into this venture, together with purchasing various merchandise I planned on using, this sort of as countless numbers of 1960s teeny-little ferromagnetic cores I picked up for a several dollars from someplace in Japanese Europe (I prepared to use these to employ a magnetic logic cupboard along with a magnetic main memory cupboard).
Regretably, I’m a bear of minimal mind, as Pooh Bear may possibly say. Also, I have a shorter notice span and I’m conveniently distract…SQUIRREL!!! As a end result, my notice wandered on to other initiatives.
After several years’ hiatus, I was released to an engineer named Joe Farr. Joe and I share quite a few pursuits, which include a love of retro computers. Considering that Joe is so central to the present-day incarnation of the HRRG, I requested him to deliver me a couple text I could use to introduce him, and he replied as follows:
I’m a eager electronics, personal computer, and radio novice. The moment I’d completed my (official) instruction in the 1980s, I began my profession as a computer system programmer for Nixdorf Computer systems positioned in Manchester, England. Just after various yrs, I relocated south (generally for the superior local climate), performing with leading technology companies on application, components, telephony, and cellular knowledge devices. Now, right after a lot of yrs in the freelance entire world, I have settled down in an idyllic nation hamlet just outside the house Cambridge in which I tele-commute to my comprehensive-time (working day) job as a senior software package and components engineer with the London Ambulance Services.
Just after extra e-mail discussions than I care to take into consideration (this was prior to video conference phone calls turned the norm), the HRRG experienced transformed into a 4-bit device for the reason that we imagined that would be much more entertaining. Also, we identified that a 4-bit computer would make more feeling as an educational software.
The recent concept includes getting a system clock cabinet, a CPU cabinet, and a bunch of memory cupboards. The notion is that hobbyists and significant school learners would be capable to make memory cabinets that contains as little as a single 4-little bit word of memory implemented in the engineering of their preference, and that these memory cabinets would then talk to the most important CPU cupboard.
Even far better, as component of this, Joe has designed an emulator of the overall process that operates on a Personal computer. This indicates you can first develop a virtual memory cabinet that talks to the digital CPU, and later on produce a actual physical implementation of your cupboard that talks to the digital CPU (or a actual physical version of the CPU if you happen to have 1).
Just to increase a good large dollop of product on to the best of the metaphorical cake, Joe and I outlined our own assembly language, following which Joe whipped up an assembler. As we see in the screenshot above, the assembler alone looks like it’s operating on a virtual Sperry Univac Uniscope 200 details terminal.
So, as you can see, Joe and I set a sizeable amount of effort and hard work into this undertaking, until…SQUIRREL!!! What can I say, we both bought distracted with other assignments, and a layer of dust started off to develop on major of the notion of the HRRG. And then…
Someday in early 2021 I been given an electronic mail from an electronics engineer named Nils van den Heuvel who hangs his hat in the Netherlands. Obtaining run across some of my earlier writings on the HRRG 4-bit laptop or computer, Nils reported he was fascinated in creating an FPGA-based implementation.
So, Joe, Nils, and your humble narrator began to have weekly conferences. There’s very little like seeking to construct some thing to reveal any holes in your structure, and the HRRG was no exception. As a outcome, we have developed the CPU’s register set and instruction set into a little something that I actually assume is actually relatively tasty. I shall share extra on these topics and introduce Nils thoroughly in my upcoming column. In the meantime, as usually, I welcome your reviews, thoughts, and solutions.