ZX81 Computer


Showcasing monthly programs, a retro look at my my first computer., Page 5


July’s Program: A Story

July’s Program: A Story

July’s program is indicative of the BASIC programs you’d find in early programming manuals. Most books start out with pretty basic commands such as PRINT and INPUT. A Story mimics these early programs in a creative way. Similar to Mad Libs, you answer a series of questions and the program, well, tells you a story.


June’s Program: Fly

June’s Program: Fly

Fly is a simple program that, in the end, is both baffling and intriguing. Looking at first like a simple shooter, it acts very differently then one and, if you don’t know the rules, will make you crazy. Once you do know how to play, though, Fly becomes simple and repetitive. Our Program of the Month shouldn’t be in this place, but it is.


May’s Program: WIZERDRY

May’s Program: WIZERDRY

Okay, you may be wondering why there is a picture of an Apple II on a ZX81 site? I’ll start by saying that it’s been a pretty busy May with lots of travel for both business and vacation. The picture is from the Smithsonian and it actually does relate to May’s program of the month, Wizerdry. Yep, I spelled that wrong. I'll chalk it up to being young. Can you guess the tie yet?


April’s Program: RMS

April’s Program: RMS

Are there any D&D folks in the audience? Come on, you know who you are. Past or present doesn’t matter, just if you know what I’m talking about. Why, you ask? Because RMS, April’s program of the month, will use your ZX81 to build monsters. Any fledgling DM could then use these creatures in their latest campaign. Elves and humans will cringe at your originality and cruelty.


March’s Program: Input One

March’s Program: Input One

Input One, March’s program of the month, is a great example of the kind of simple and brute force programming of the 1980s. This was a time when computers had little memory and their users had to use simple BASIC programming to get things done. The alternative was to buy a cassette tape of programs that took minutes to load even short programs, assuming they loaded at all. For the rest of us, we either typed them in or wrote little programs like this.


February’s Program: Math Bash

February’s Program: Math Bash

At the one level, you can sum up most programs into three big groups: business, gaming, or educational. Most of my programs fit into one of these base categories. The standouts are generally the animation or demo programs that really have no distinct genre. Even those, however, I can lump into one of the big three without much effort. There are times when these categories get blurred and a program can fit into two or more categories. This month’s program is one of those.


January’s Program: Comp. Talk

January’s Program: Comp. Talk

Mixing things up a bit, I thought I’d start off the new year without a game program. Instead, January’s program is Computer Talk, or Comp. Talk for short. Comp. Talk is one of several educational programs I wrote for reasons I’m not entirely sure of. Perhaps it was just the thing to do back in then. Many computer books, especially those that taught programming, had a mix of program genres. Whatever the reason, I wrote Comp. Talk as a way for the ZX81 computer to introduce itself and show a bit of what it could do.


December’s Program: V Water Battle

December’s Program: V Water Battle

As 2014 comes to a close, I wanted to end the year with an original program of the month. For December, that program is V Water Battle, an action game from 1984. For some reason, the title screen I created said designed instead of wrote but I did both. I was an odd duck in 1984. You use the “Z” and “.” keys to move. Use the “M” key to fire. The goal is to stop the ships from stealing the water. Miss them or get shot and its game over. Of course, they steal the water after each wave anyway to make it harder. Given that I haven’t beat it yet, the game is more difficult than it would seem. Let me know if you do!


November’s Program: Maze Craze

November’s Program: Maze Craze

Hope everyone in the US had a great Turkey Day (Thanksgiving) and are now enjoying the last weekend of November. I’m busy with NaNoWriMo, and a bit behind. So I give you another program from my original ZX81 site, but not yet featured here. November’s program is the month is Maze Craze. It’s not hard, but you might need to graph out the maze if you get stuck. There are actually two mazes. Can you beat them both?


October’s Program: NA

October’s Program: NA

Whoa, there are still almost two weeks left in the month and I have October’s program done and waiting for you. Yep, you heard right. This month is a short one called NA. The program is an action game that requires you to use “N” and “A” to try to stop a runner. The letters have significance as you use them to stop the runner. However, there is a twist, miss and the program changes the letter needed. Sounds easy right? Guess what, I still haven’t beaten it. Can you?


September’s Programs: Photon ’85 and ’98

September’s Programs: Photon ’85 and ’98

Well, the month is over and life has taken over and delayed my program of the month. For the tail end of September, I offer two programs: Photon and Photon 98. Wait, what? Yep, you heard right. I’m offering two programs this month. Sort of.  Actually they are very similar. Photon is the original program from 1985, and Photon 98 is a minor remake that cleans things up a bit.


August’s Program: Cave War

August’s Program: Cave War

August’s program is Cave War, a later program from 1985. It starts out similar to Hit Man, basically a scrolling dodge the wall game. But there is more to it than that. Once you get to the end of the tunnel, you find yourself in a cave and need to blast away at a wall to continue on. Oh, and if you hit the same spot twice, it resets. Can you make it out of the cave alive? Use “Z” and “.” to dodge the walls and “X” to blast away the ground. Good luck!


July’s Program: Block £ Spear

July’s Program: Block £ Spear

Sorry, still no Joust. It’s not where I want it and I’ve spent July working on my novel instead. That isn't to say that I’m going to leave July without a program of the month. Instead I’ve pulled from my original site to bring you one of my favorite programs, Block £ Spear. In this game you'll find yourself at the wrong end of a knight’s spear. Fortunately, you have a shield and can easily deflect the spear by using the Z and . keys to raise or lower your shield. Sounds easy? You might be surprised.


June’s Program: Monster Maker

June’s Program: Monster Maker

Okay I haven’t finished my remake of Joust yet, nor did I want to wait until the last week of the month to get an article out. Instead, I offer you Monster Maker as June’s monthly program. It’s pretty straight forward and anti-climatic against the power of today’s programs. Once you load it, enter in five numbers and type your monster’s name. That’s it. The program will then display a nicely formatted monster description based on your input.


May’s Program: Joust

May’s Program: Joust

I actually started working on May’s program of the month, Joust, about three weeks ago. My goal was to update the program to a faster and more fluid MCODER version. Sadly, things haven’t gone so well. Pressed for time, I will leave you instead with my original take on this popular arcade from the 80s.


April’s Program: Flywheel

April’s Program: Flywheel

April has been a crazy month. I decided to try something new, pushed along by an unexpected event. I’m writing a book. I joined NaNoWriMo just after last November's event so I didn't expect to do anything until later this year. The surprise was their CampNaNoWriMo event in April. Not to waste the opportunity, I’ve been busy crafting my Sci Fi novel and am now in the final stretch to my 50,000 words goal. Add on top of that a business trip and a family trip and you'll quickly see that my ZX81 hobby gets pushed by the wayside.


March’s Program: The Ball Redux

March’s Program: The Ball Redux

For March's program of the month, I drew inspiration from one of my older demo’s, The Ball. Like many young kids from the early eighties using BASIC, I took a stab at animating a bouncing ball. It is a a relatively easy program to write depending on how complex you want to make the math. In my case, it is very simple math, no physics involved here.


February’s Program: Time

February’s Program: Time

For February, I give you Time, a simple landing game with a twist. Using the Z and . keys, you maneuver your craft to each successive landing pad. If you miss the landing, keep trying but be careful. Run out of time and it’s game over! How high of a score can you amass? A fair warning, Time isn’t always fair.


January’s Program: Fireball

January’s Program: Fireball

January’s program of the month, Fireball, marks a first for me. Although I’ve used a few different methods to type in my programs, I’ve always gone back to a Windows so I could use EightyOne to generate the program files and images. However, for my birthday, my wife took me to the Apple store and I upgraded my old laptop to a shiny new MacBook Pro.



November’s Program: SNUNCH ML

November’s Program: SNUNCH ML

For November, I’m looking both forwards and backwards. Although I wrote SNUNCH in 1983, I added a corrected version to my first ZX81 web page in the ’90s. SNUNCH was my early attempt at writing a PAC-MAN like game. Note that I said like, not clone. My goal was to be inspired, not to copy. Sadly, it isn’t very good, even after I fixed some of its logic flaws. Despite its flaws, I still believed it had potential and I set about updating it using MCODER II. It is this improved SNUNCH ML version that I offer as November’s program of the month.



Doing Some Fall Cleaning

ZX81 Computer

I took a break from educating myself on z80 machine code, more on that later, to fix a few things that have bugged me about the site. They are minor and probably will go completely unnoticed by most, but I wanted to make a quick note for future reference. Hey that’s what blogs are for, right?