Archive for the ‘80’s’ Category

I’ve learned few weeks ago about the Retrochallenge that happens every winter and summer, which is , according to its website,  a loosely disorganized gathering of RetroComputing enthusiasts who collectively do stuff with old computers for a month. The challenge will be held from July 1st to 31st.

Excited about it, and with tons of interesting stuff to do but very little will power, I decided to enter this year as a way to motivate myself to do something new retro-wise.

I know this is a Commodore 64 blog, but I am a big fan of all 8-bit machines I can put my hands on, so for this challenge I’ve decided to do something with my latest acquisition: an Atari 600XL! To keep the Commodore lovers under control, I’m calling this challenge the Blasphemy Edition, since I am going to use a less sacred machine. Don’t worry Atari lovers, I’m saying that only to please the Commodore lovers. Don’t worry Commodore lovers, I’m saying that only to please the Atari lovers. Don’t worry….(repeat until you get tired).

Here is my challenge proposal:

– Create a game in BASIC that uses graphics and the player/missile resources. The game will be simple but it has to use those techniques – theme is still TBD (it will be defined before July 1st)
– All the work will be done in the actual Atari 600xl with a cassette tape as storage device. I won’t be using any modern resource like emulators, SD2PC devices, etc.
– I will be blogging the experience in at least a weekly update here under the title “Retrochallenge 2014 – Blasphemy Edition”
– The final result will be made available for download at my new website as soon as I can send the program to my PC (I don’t have the means to do it right now)

If you want to follow me during this journey, subscribe to the blog or follow me on twitter!


Retrochallenge 2014 website:


My first Commodore PET

Posted: May 3, 2014 in 80's, Commodore 64

I finally have one! For a long time I wished to have one unit of the first Commodore personal computer, and the time has come! The only detail is that in my case, PET stands for Paper Electronic Transactor!

Yes, while I cannot have a real one, I am very happy to have a miniature made of paper. Here is the beauty:


My paper model of a Commodore PEt

My paper model of a Commodore PET

My son was always interested in build paper models, and the Internet has thousands of thousands of everything that you can imagine to be built using paper, mostly using the software Pepakura. Seeing him having fun with something he was building I wondered if there was any paper model of Commodore computers.

For that specific software I didn’t find any, but I was able to find two Commodore paper models that you can download, print, cut and build yourself.

The first one is my PPET (Paper PET), available as free download at the German website HomeComputer Museum, and it is very

PPET hanging out with its great-grandson!

PPET hanging out with its great-grandson!

easy to assemble. It consists in three sheets of paper containing the base, the main case and the monitor.

The second model I’ve found is a Commodore SX-64, and the author, Erik Schubach, made the sheet available for free on his website: I haven’t tried this one yet, since it seems a bit more detailed, but I will build it soon.

I would recommend to print the sheets using 120g or 180g paper, so you can get a sturdier finish model. To cut the sheet I used a Xacto knife. It is also useful to make the paper to fold easier. For that, apply the knife very lightly over the lines meant to be folded. White glue is perfect for that, although hot glue is better if you know how to use it without making a mess.

If you know where to find more paper models for Commodore computers, please leave a comment. If you are talented enough, try to make a new one using the Pepakura Designer – I will be thrilled to see and try your work!


Sleeping with the enemy

Posted: February 20, 2014 in 80's

Yesterday I’ve got a TRS-CoCo II working, hooked up with my Commodore monitor. They didn’t get along at first, but after a while, they were friends, or maybe polite acquaintances 🙂

Commodore and Tandy having a good time

Commodore and Radio Shack having a good time

Although I still think the Commodore 64 is a better machine overall, the TRS-CoCo is actually very powerful. The Extended Colour BASIC is way more powerful than the crazy peeks and pokes I have to use on C64 BASIC. Commodore did way better with the BASIC 7.0 used by the Commodore 128 and other models, which is very similar to the Extended Colour BASIC commands. The code above is not even worth explaining – I was just randomly plotting some graphics and playing some notes.

This article was first published on The Transactor volume 4 issue 02 (January 1983) by Paul Higginbottom. I recently found him and asked for permission to reproduce this article here, and he was very kind to give it. After reading tons of texts about SID, his article was the first that actually I could understand, so I really wanted to share here.

Paul Higginbottom can be found on his blog ( and,  since 2005 he has been creating websites and other media, and providing professional technology consulting to individuals, businesses and other organizations across the world through his company Reora, Inc

Making Friends with SID

Paul Higginbottom

The synthesizer chip in your Commodore-64 computer is affectionately known as SID. SID is in fact an acronym for Sound Interface Device. I doubt that many people realise just how powerful this chip is, but I intend to unleash some of its power for you. If you read some of the documentation for the Commodore-64 about its sound capabilities and are new to synthesizer jargon (as I was), you probably thought to yourself, “I’m never going to figure that out!” Well, l am the sort of person who gets more determined to figure something out when it seems harder than ever to do so. So, step by step, I, like any beginner, set about learning how to control the SID’s sound capability. (more…)

Mission:Moon gameplay video

Posted: September 2, 2013 in 80's, Commodore 64, Programming

So I finally did it! Mission:Moon is complete!

Soon enough I will make it available for download, but meanwhile I took my Betamax camera and shot this short video. Enjoy!

I’m almost done with Mission: Moon (check my last post here). Yesterday I was adding some intro screens, fancy text, etc… When I tried to run it once more, bad things started to happen – things that when you see, you know you are putting code over something important.

After some digging, I realized that the game has grown to big and it was overwriting all my sprite definitions and other stuff. When I first started I put all eight sprites after the address ~15,000 to have enough space, but unfortunately it wasn’t enough. My program has around 12kbytes and the Commodore has around 38kbytes free, right? So it is easy to fix that, right? Move the sprites up, right? Wrong! (more…)

My new The Beaver issue

My new The Beaver issue

Nowadays, we have plenty of good magazines dedicated to the Commodore family, here in North America and also in UK – I’m talking about magazines in English only.

Compute Gazette is one of my favorites, followed by some British ones, like Your Commodore. They are good because it covers everything, from games and application reviews, type-in programs, BASIC and Assembler articles, etc.

This week, when I went to the newsstand to buy the new issue of The Beaver, I’ve found a magazine called The Transactor. It is not new or anything, but I simply didn’t know it exists. After reading the issue I bought, I’m sold to this magazine. It is very simple-looking but all articles are so deep that I have to say that this is now my favorite magazine. I will probably keep reading the others, but The Transactor is really a source of technical articles about Commodore computers that you won’t find anywhere else.

The Transactor #1

The Transactor #1

Current Issue

Current Issue

The Transactor actually started not long ago as a 14-page bulletin published by Commodore Canada, but now is a fully-featured 80-pages magazine.

The issue I’m reading is really rich in information, covering things like Subroutine Eliminators, Inside the Commodore 64, Fixing Commodore Keyboards and so on.

If you don’t know about it already, learn more about it accessing this BBS link.