Playing with portable power

Casio’s catchily named PB-100 launched in 1983, and while not cheap (it cost about £50 at the time, which is roughly £170 today) it was always intended to be a reasonably basic BASIC-compatible pocket computer and so has a feature set to match. This relative lack of power comes with one big benefit: Battery life. According to the manual (and borne out by my own experiences) two fresh CR2032’s last around fifteen days. Now if that meant “fifteen days” in the way we expect it to these days – just over two weeks of occasional calculation and programming coupled with some time off in your pocket before it runs out of power – that’d be impressive enough, but what the manual means when it says “fifteen days” is fifteen days of constant use. To put it another way, this will work for three hundred and fifty hours before you need to change the batteries. From where I’m sitting I can see an iPad, Game Gear, laptop, DSi, and a fancy folding phone – this little computer, almost literally as old as I am, would easily outlast them all even if it was pitted against them consecutively in some nerdy reimagining of a fight to the [battery] death tournament.

More troublesome and also less impressive is the half a kilobyte of memory it comes with as standard (there’s a memory expansion slot on the back if you need it, capable of accepting an extra 1KB). How big is half a KB? Saying “not a lot” doesn’t really help so let’s use a real-world example to make it clear: The plain text draft of this article weighed in at around 5KB, and that’s before I’d got close to finishing it up. Charmingly this dinky scrap of trouserable memory can be split however you like between up to ten separate programs – why would you want to do that? Well apart from the obvious convenience and futuristic technological might that comes with carrying multiple programs around with you it’s handy to have a working and saveable “scratchpad” to hand without having to nuke everything else you’ve written (or painstakingly backed up to tape), and better than that you can also call from one program to another, which gives you the opportunity to write differing main programs that both neatly refer to the same separate GOSUB (and back again, code willing), or simply compartmentalise a larger program into easier to manage chunks. It’s such a handy feature I honestly wish every pocket computer had it.

To help ease myself in to some meaningful fiddling I type in a little golf game given out for it at the time and after much prodding at my shiny metal rectangle… it almost works. Which is pretty much business as expected, and also half the fun of copying a program in this way. The good news is that during this extended typing session I learned that the shift key can be used to automatically type in basic commands – PRINT, FOR, NEXT, RETURN, etc, filling them in at the push of two buttons. Hitting shift+H and seeing GOTO instantly appear on-screen followed by a space feels nothing short of luxurious.

So, what should I do with this newfound power?

Sadly any form of graphical trickery is completely impossible no matter how much POKEing I do (the golf game mentioned earlier was all numbers and YOU WIN!) so have to rely on the existing character set to represent everything. I could, maybe, make a little dungeon crawler that looked like this – ]S[ – (that’s a powerful Dreadwyrm standing between two stone walls covered in moss) or this – .*[ – (that’s a floating orb with a stone wall on one side and empty space on the other), but it’s too abstract for me to really get a grip on, and doesn’t feel much fun to struggle with. I suppose the best course of action would be to use this pocket computer to actually compute something; Eighties programming manuals are full of “useful electronic helpers” with bland names like STAT-O-TRON and COMPU-SCHEDULE after all.

And you know what? For a minute I seriously considered it. I could write something like that, couldn’t I? But it’s also kind of boring, don’t you think? I’m staring at a beautiful Eighties pocket computer that looks an awful lot like an early Shin Megami Tensei COMP, it’d be a shame t-


Not a real one of course – although I’m not sure the world would notice if I managed to successfully call forth the denizens of Hell considering the way things are at the moment – but something that visually mimics that sort of behaviour. I could write a simple ASCII “animation”, include some sort of demon list… yeah! Let’s get to work!

With the age and format “let’s get to work” means digging out my trusty journal and pencil rather than sitting down to type anything out. It’s a nice way to work. Doodling gives my brain space to think and the little notes in the margins and scribbled arrows linking various ideas help it all come together quickly. So it isn’t too long before I’ve slid the PB-100’s satisfyingly chunky power button into the “On” position and… I soon discover this device has some [more] funny quirks. There’s one good one: The screen auto-scrolls any text that’s too long for the display in a pleasantly retro-tastic way, and that’s great because any message longer than twelve characters is too long for the display. There’s an indifferent one too: While this little Casio will happily let you smush lines of code together so long as you stick a colon in between each segment you can only have a maximum of sixty-two characters per line, including the line number. Sixty-two characters is about a quarter of a tweet, and makes writing a list containing the more elaborately named deities something of a non-starter. I thought I’d be clever and go with Set, Re, and similar instead, but in context those names look more like half-written lines of code than gods awaiting your command. And then there’s the bad one: Printed text essentially halts the program, so any time you display a message you have to then manually hit the EXE button to carry on – something of an issue when you’re making a program (“program” is an overly generous descriptor here) that’s pretty much nothing but printed text and completely kills any chance of me making a little “animation” either. I had plans for a quick looping “pulse” to appear when you “summoned” a demon, something that looked like this –


– but with that out the window and all the other snags on top I realise it’s probably best to leave COMP programming to Stephen after all.

In spite of my own pitiful efforts the PB-100’s a lovely little thing; it’s a genuinely pocketable pocket computer that’s sturdy enough to not need any great amount of care, is easy to use without any memorisation or manual thanks to the clear colour-coded key symbols (and the little menu printed next to the display too), and has enough oddities of its own to make it more than just another single line display BASIC machine. And if you’ll forgive me for sounding like a recently unearthed relic from a bygone era I’ve honestly enjoyed having a proper calculator, one with physical buttons that isn’t going to suddenly tell me an item in my Steam wishlist is on sale or that it’s almost bedtime, within arm’s reach.

And if you’ve been looking at the photos of this device and caught yourself thinking “That looks a bit familiar…” then congratulations, you’ve noticed a prop used in 1984’s smash hit movie, Ghostbusters. I know, I know… I can practically hear your disdainful sighs from here. But it was an honest coincidence, I swear (in all seriousness: It really did just happen to be the cheapest fully working retro pocket computer for sale on the day –  Brownies‘ honour). Anyway! The one seen dangling from everyone’s favourite nerd in the screenshot below is the rebadged Radio Shack TRS-80 model, which is identical to this Casio in every single way other than the branding.

If my utter hopelessness was ever in any doubt… well. 

[Ko-fi supporters: I love you, and this is all your fault. Thank you!]

5 thoughts on “Playing with portable power

  1. You can PRINT without halting the program by putting a semicolon at the end of the line.

    This little demo program draws an animated “power meter”. Press 5 to stop the meter and show what “power level” you landed on.

    10 $=“ ?▪️”:P=1
    20 PRINT CSR I;MID(SGN(P)+2,1);
    30 I=I+P
    40 IF I>11;P=1:I=11
    50 IF I<0;P=1:I=0
    60 IF KEY=“5” THEN 80
    70 GOTO 20
    80 PRINT “Your power:”;I


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