Intermission

So, is fair to say that things have been a bit quiet around here of late … and if you’ve been following my YouTube channel I do hope you haven’t been holding your breath for the next episode of ‘making a relay computer clock’ as the last episode came out just over a year ago!

What’s been going on then? Well first of all I’m fine (and actually writing this on one of the lazier days of a holiday in Crete … so I’m especially ‘fine’ and relaxed) but like most people the Covid lockdown has had its impact. My day job was always quite busy but over the last couple of years it’s been particularly busy and then combined with not having holidays to recharge I’d frankly lost all interest (and time) for my hobbies. Normality ultimately returns though (even if it’s a ’new normal’) and so does my appetite for hobbies.

Does this mean I’ll be full steam ahead on the relay computer again then? Well not necessarily. Notice above that I mention ‘hobbies’ and not ‘hobby’ as there’s a ton of things I like to get up to … generally anything within a theme of ‘making stuff’ … so DIY home and garden improvements feature highly, I also quite fancy making some more batches of wine and it’s been a while since I got the sewing machine out ;)

One thing the last couple of years has taught me though is to go with my mood and not turn a hobby into just another form of work. YouTube videos are a particular case in point here as it takes a lot of effort (more than you potentially think) to film and edit down a video to something remotely watchable (and I’m definitely a YouTube novice in that regard).

So, what does this all mean for my YouTube channel, this blog and ultimately my relay computer? Well, I am still here and I’m still interested in building my computer but it’s going to be a bit more spread out (hopefully not year long droughts of content though) and I might mix up what I work on a bit to keep it more interesting for me.

Something you may or may not know about me is I’m a software engineer by trade. I ended up in a management role though so I’m a bit rusty but the interest and love of code is still there. This occasionally surfaces in my hobbies and like most coders I have a ‘pet project’ I occasionally play with to learn new frameworks and try and keep the rust away from my programming fingers. Why am I telling you this? Well it just so happens that I have been working on my relay computer the last couple of months but maybe not in the way you’d expect.

If you have been following my work and videos you’ll know programming a computer (any computer) in machine code (1s and 0s) is a pain and so using an assembly language makes that a bit easier. Problem now is that you need something to take the assembly language program and convert it to machine code … an assembler. Well that’s what I’ve been up to. If you’re curious you can find my GitHub profile here that contains my assembler, this blog plus a host of other bits and bobs. I’ll be doing a post soon that explains more about the assembler but if you want to have a play the end result is here and using this you can make programs and run them on a simulation of my relay computer here.

Other than that then what’s coming up - well what was true in my 2020 update videos is still true now and the todo list looks something like this:

  • Finish off the clock card
    • Prototype full relay clock circuit (with halt and restart)
    • Design digital secondary clock (higher accuracy, variable speeds but inauthentic)
    • Prototype digital secondary clock
    • Design PCB for dual clock
    • Build dual clock
    • Fit clock to computer and test/demonstrate
  • Add instruction classes
    • Load/Store - to copy values between registers and memory
    • Mov8/Mov16 - to copy values between all main registers (8 bit and 16 bit)
    • IncXY - to increment the XY register (useful for indexing operations and stacks etc)
  • Upgrades
    • Replace wire wrap cards with PCBs
    • Replace old backplanes with stacked PCBs
    • Replace power distribution board with PCB equivalent
  • Rebuild enclosure/case enabling:
    • New ‘DisplayC’ which will be a very low resolution matrix display
    • New paper tape reader (for easy entry of programs)
    • Landscape case rather than portrait making videos much easier to record ;)

You’ll notice that most of the above fits in to the same ‘hobby’ category so this is where I’ll break things up a bit by working on the relay computer simulator and assembler but also, of course, the aforementioned ‘other stuff’.

I’ll leave it there for now then but if you want a bit more context for my ’todo list’ above the video below (which followed the 2020 update series) provides just that: