Old Skool Blog

For those of you into podcasts, the Retrobits Podcast is a weekly journey into old school computing. Shows are usually around 30 minutes long and Earl focuses on a single topic each week. The current episode is devoted to the Tandy Model 100 and previous topics have included the 6502 Processor, The Z80 Processor, The Epson PX-8, book reviews, classic computer expos, etc.

New episodes usually appear every Sunday and if you are in any way interested in old school computing, I’d highly recommend you go check the Retrobits Podcast out.

2001: A Space Odyssey is one of my favourite movies of all time. I never realised the significance of the song that HAL sings as he is shut down until I read this blog post. According to Wikipedia, Arthur C Clarke was so impressed with hearing a speech synthesis demonstration at Bell Labs in 1961 that he used the song in the climactic scene where HAL is shit down.

You can hear a recording of the demonstration here. (The clip is only about 2 minutes long - HAL’s song is near the end.)

I just came across the very first computer I ever built. Now I don’t mean plugging a CPU into a motherboard - to build this computer I had to solder in all the resistors, transistors, diodes, capacitors, LEDs, switches, chips etc.

The Microcomp-1 was a kit computer, produced by a small electronics magazine called Talking Electronics. This is a very simple computer based on the Z-80 CPU, with a stunning one whole byte of RAM and 16KB of EPROM storage. (The “one byte of RAM” is just an output latch to make driving the LEDs easier.) The input options consist of two micro-switches (labelled A and B on the board) and a “probe” (the orange fly-lead) which can be used as a simple logic-probe. (The probe is directly hooked up to the speaker.) The 8-way DIP switch is used to select the starting address in the EPROM.

Output options are two 7-segment LEDs, a  4×4 matrix of LEDs and 8 single LEDs. All three output options are on the same output bus, so they will all display the contents of the output bus, just in different ways. The rows of the 4×4 matrix is driven by the low 4-bits of the output latch while the columns are driven by the upper four bits. Using some simple multiplexing, it is possible to individually address each LED.
The clock speed is adjustable using a small trimpot (on the left hand edge of the board with an LED soldered to it to make it easier to turn) but I cannot for the life of me remember what speeds it was capable of.

This was a great little kit to build - I learned a lot about the design and operation of microcomputers using this. When I get some spare time I will dig out the manual and see if it still works…

I just found this documentary on YouTube about two of the big game companies in the 80s - Imagine and Ocean. Included are some interesting insights into the mythical game Bandersnatch and the demise of Imagine.
There are three parts and the total length is about 30 minutes.
Part 1

Part 2

Part 3

I can still remember the first time I ever saw a Space Invaders machine. It would have been 1979 and my father had taken me to Melbourne for a day trip and while we were there, we went into one of the new “video arcades” to kill a bit of time. Pong, Breakout, Sprint 2 and a smal handful of other games had already become quite popular, but on this day there was a new machine that caught our eyes - Space Invaders! Within minutes we were hooked, although we both sucked at the game.

One of the novel features was the way the invaders sped up throughout the game, which meant your skills had to be spot on or you would soon be wiped out or over-run. Back in the early days, it wasn’t possible to play video games all day, so I had not quite developed the hand-eye coordination required to even clear a single level on that first day.

In the months that followed, more and more games started to appear in the arcades, but Space Invaders always had a special place in my heart.

If you ever played Space Invaders, you might enjoy this video. I found a link to the creator of the video, but the site is in French…

Remember when computer magazines had pages and pages of type-in computer programs? Compute!, Compute’s Gazette, Run, Commodore Magazine, Antic, InCider, Your Commodore, ZZap 64, etc… Each month these magazines (and many more) would have anywhere from 10 to 20 pages of programs you could type in, mostly in BASIC, but it was not uncommon to see some machine language and even once or twice I remember seeing some more obscure languuages such as Logo and Forth.

After spending hours typing in a multi-page program you would anxiously save to tape (or disk if you were lucky enough to be able to afford a floppy drive) and then RUN the program. Then would begin the laborious task of trying to track down the inevitable typos you made. If you knew how to program in BASIC and if the program you were typing was in it was surprisingly easy to pick up typos as you entered the code. If the program was machine language though, it would typically be presented in the form of a BASIC “loader” with reams of DATA lines jammed full of hex codes. Those were a b*tch to debug! 8^/

But when you did get the program working it was so cool. Sure, some of the programs presented were very simple and almost useless (especialy in the early days) but there were plenty of gems to be found in the magazines. I still have piles of tapes just full of programs typed in from magazines and books. Games, programming tools, utilities, productivity and business software - you name it, it’s there. In fact, one of the best early word processors was a magazine type-in - SpeedScript first appeared in Compute!’s Gazette in 1984.

What are your memories of typing in programs from magazines and/or books?

You guys just have to check out this ad scan from VintageComputing.com!

Yesterday I received an email from a fellow collector in New South Wales, offering me his collection. I’d love to take it off his hands, but there are two small problems:

1. He lives about 920km away; and
2. There are over 40 computers on the list he sent! I doubt I’d have the room to store them all!

I’d really like to take at least some of the computers off his hands so I’ll see if he’ll let me cherry-pick the ones I want. I just have to work out an affordable way to get them shipped here…

Sometime in the early 90s I acquired a PET 2001 via the Trading Post. A 2001-16N to be precise - 16KB RAM, full keyboard, external tape drive. I paid more for shipping than I did for the computer itself - the thing weighs a tonne! The casing is made out of steel - not the plastic that most dinky home computers were made out of!
To be honest, I have never done a great deal with the PET. It hooks up to standard Commodore tape drives (so it is a trivial matter to transfer data between a Commodore 64 and the PET for instance) but I have no other peripherals such as disk drives) for it.

The PET uses Commodore BASIC (v1 I presume - there is no version number) and starts up with 15,359 bytes free. Unfortunately there are no graphic capabilities to speak of apart from the PETCSII graphic characters. The characterset is stored in ROM and unlike later Commodore computers, the characterset cannot be copied to RAM and modified. Also, there are no lowercase characters available - uppercase only.

I’v just plugged it in and turned it on - the inbuilt 9″ monitor is still looking nice a crisp even after all these years. (No, I was never tempted to try the killer poke!) About the only problem with the old beast is some of the keys are not terribly responsive, but that should be easily fixed with a little cleaning and TLC. Please excuse my while I indulge…
10 PRINT "OLD SKOOL COMPUTERS ROCK!"

20 GOTO 10

RUN

I remember designing a game on my Vic-20 not long after I first started writing programs for the wee beastie. It was an overly ambitious game, given my sorely lacking skillset at the time, but I remember part of the premise: You had to parachute onto an island, guiding your character to a safe landing a la Lunar/Moon/Jupiter Lander. Once on the island, you had to locate several items then build a raft/boat before navigating your way back to the mainland. It would have been a cool little game and I did get some initial code written but never got beyond the initial parachute stage. (And even that didn’t work quite as I intended. ) I found a couple of the initial sketches I made for the game when I was digging through my Vic-20 stuff the other day…

My next foray into game programming was more successful, though much less ambitious. It was for the Commodore 64 and was my first attempt at using sprites. The concept for this game was very simplistic - you controlled a hand holding a can of fly spray and you had to spray as many flies as possible in 60 seconds. I drew all the sprites on graph paper and laboriously calcuated the correct values to POKE into memory.

I didn’t actually own a Commodore 64 of my own at the time - I would write the code on my Vic-20, save it to tape, then take it around to my friend’s house and load it up on the Commodore 64. Surprisingly, the game worked first time and we had a lot of fun playing around with it.
After that success, my game-writing career turned to text adventures and I never quite reached the heady heights of graphic prowess of that original Fly Spray game!