How-To - Imapenguin

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A collection of 32 posts

Dice frequency

I've been obsessed with the Random number generator on the Commodore computers for a LONG time, and I'm not the only one who is, to be sure. We've used this random function in many of the Cipher series articles before, both via BASIC and directly getting randomness from the SID

A week of diving a little deeper into my Atari 800XL

A week of diving a little deeper into my Atari 800XL

I'm a Commodore guy through and through. This isn't tribalism, it's what was in my room from 1983 to when I graduated High School in 1993. After my sorta failed attempt at spending the month of September with my Coco 2, I decided for October to try spending a week

Two weeks with a Coco 2 in September

Two weeks with a Coco 2 in September

In the inside baseball realm of vintage computer enthusiasts, a few hashtags have emerged to support one's favorite retro computers. The main one in September is #SepTandy While I've had this Tandy Color Computer 2 for many years, I've almost never used it. Out of all of my vintage systems,

Slot Game On Tandy TRS-80 Pocket Computer PC-4

Slot Game On Tandy TRS-80 Pocket Computer PC-4

One of my first ever real programs was a blackjack game I made in BASIC on a Sharp 9300 calculator to impress my Adv. Algebra teacher. I have seen the handwritten copy of this somewhere around here recently, but I'll be darned if I can't find it now. Slot Game

Calculating Pi via the Gregory-Leibniz series in BASIC on the Tandy Color Computer 2

Calculating Pi via the Gregory-Leibniz series in BASIC on the Tandy Color Computer 2

Back in March, we did a simple set of programs to brute force calculate Pi using a simple and well-known series. It works, even if it's inefficient. Speaking of inefficient, it's September and that means it's time for #Septandy! I have a Tandy Color Computer 2 - 16k of RAM

Just for fun, the 100 door problem on several different systems

Just for fun, the 100 door problem on several different systems

What's the 100 door problem?It's a just for fun problem in "beginning" math and computer courses. The idea is simple: There are 100 closed doors in a row. You walk past the doors 100 times (100 passes) The first time, visit every door. If the door is closed, open

Running Commodore 64 BASIC Programs on a PET

Running Commodore 64 BASIC Programs on a PET

The Commodore 64 and PET are fairly similar systems. Other than a few memory location differences, many BASIC programs written for the Commodore 64 that don't use graphics can run on a PET. There is one caveat. The PET doesn't relocate a saved BASIC program to the beginning of BASIC,

The CERBERUS 2080

The CERBERUS 2080

A few months ago, I stumbled on a project that really caught my attention. Mr. Bernardo Kastrup, aka TheByteAttic finished a video series on a computer he designed and built "by hand." It's an impressive amount of information. Clocking in at more than 12 HOURS. Total time of his videos3

Making and breaking Ciphers on the Commodore 64, er VIC-20 - Lagged Fibonacci Sequence and a little Monte Carlo while embracing contraints

Making and breaking Ciphers on the Commodore 64, er VIC-20 - Lagged Fibonacci Sequence and a little Monte Carlo while embracing contraints

We're on ANOTHER random number generation technique today. Let's work on the Lagged Fibonacci Sequence, a fun way to use the Fibonacci Sequence on itself to generate pseudo-random numbers. One of our long term goals is to add a bunch of tools to our toolbox. Making reusable components makes doing

Running the 8 Bit Show and Tell VIC-20 Super Expander Programming Challenge on the Commodore 64

Running the 8 Bit Show and Tell VIC-20 Super Expander Programming Challenge on the Commodore 64

One of my favorite videos on the whole internet lately is this hidden gem by Robin. In it, he executes a programming challenge he found on Twitter to draw a pattern without using IF statements. His approach is one of my favorite math tricks of all time, and I was

Making and breaking Ciphers on the Commodore 64 Part 12 - Pontifex - Solitaire from Cryptonomicon

Making and breaking Ciphers on the Commodore 64 Part 12 - Pontifex - Solitaire from Cryptonomicon

Cryptonomicon Pontifex/SolitaireWe're back to my favorite book for another round. We've done quite a bit with Cryptonomicon so far. One of my favorite moments is when Enoch Root introduces a cipher that two prisoners used to communicate using just a humble playing card deck. Drawing of the mine in

Making and breaking Ciphers on the Commodore 64 Part 11 - One time pads on a Commodore 64, probably a bad idea

Making and breaking Ciphers on the Commodore 64 Part 11 - One time pads on a Commodore 64, probably a bad idea

A while ago, I explained in detail how to generate one time pad sheets and use them to encrypt and decrypt messages. It turned out to be doable, only requiring a pencil and a way to create random numbers, but it's slow, error prone and tedious. WhyThe one time pad

Making and breaking Ciphers on the Commodore 64 Part 10 - Finding hash collisions with a type in game from 1984

Making and breaking Ciphers on the Commodore 64 Part 10 - Finding hash collisions with a type in game from 1984

HashesWe did an implementation of a once popular hashing function in Part 8 on RC4 without really going into why. A hash function is any function that is used to map data of an arbitrary size (input) to a fixed size output. An algorithm is applied to the input and

Making and Breaking Ciphers with Commodore 64 Part 9 - Finding Smallish Primes

Making and Breaking Ciphers with Commodore 64 Part 9 - Finding Smallish Primes

RecapSo far we've Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number looking for matchesLearned how to use XOR to recover dataCreated a Linear Feedback Shift Register to generate better random numbersImplemented

Quick Post: Slow text on the Commodore

Quick Post: Slow text on the Commodore

An "almost teenager", Josh, sent me an email yesterday asking how I do slow text on the Commodore. He is just starting assembly at 12 which is pretty impressive. He's been using KickAssembler, but wants to try it "on hardware". It's not difficult really. There are probably a lot of

The Commodore 64 N.O.O.C.U.L.A.R. futbal project

The Commodore 64 N.O.O.C.U.L.A.R. futbal project

ConceptI'm fortunate to have a number of vintage computers I've collected over the years. Some were fun finds, others donated. One I've had since 1983 (we think) and it's one of my most prized possessions. I travel a fair bit and not long ago I was looking for something for

Making and breaking Ciphers on the Commodore 64 Part 8 - RC4

Making and breaking Ciphers on the Commodore 64 Part 8 - RC4

RecapSo far in this 8 part series on doing weird things with Ciphers on old computers we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number looking for matchesLearned how to use

Repairing a Commodore 128 and DIY Chris's RAM tester review

Repairing a Commodore 128 and DIY Chris's RAM tester review

I have several items from DIY Chris that we'll review over the next week including a GAL PLA and flash-able ROM drop in that can hold kernal, character or BASIC ROMs. First on the list is the RAM tester. The problem child 128I have a Commodore 128 which developed a

Making and breaking Ciphers on the Commodore 64 Part 7 - Pseudo Random with Linear Congruential Generators

Making and breaking Ciphers on the Commodore 64 Part 7 - Pseudo Random with Linear Congruential Generators

So far in this 7 part (shocked I've made it through 7!) series on doing weird things with Ciphers on old computers we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherChanneled our inner John Connor by cracking ATM machinesSearched through a large number

Making and Breaking Ciphers with a Commodore 64 - Part 6: XOR is Magical - Data recovery

Making and Breaking Ciphers with a Commodore 64 - Part 6: XOR is Magical - Data recovery

ReviewSo far we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherFaked it, but then looking for a 4 digit known pinSearched through a large number looking for matchesWe now have most of the basic skills in Assembly to start doing some real work.

Jiffies in Assembly

Jiffies in Assembly

Many of you know that you can use a "Jiffy" on a Commodore as a measure of time. Sorta. The short short version is that we have a 3 byte clock that increments once every interrupt, so 1/60th of a second. It's not considered reliable as a real time

Making and Breaking Ciphers with a Commodore 64 - Part 5: Wargames

Making and Breaking Ciphers with a Commodore 64 - Part 5: Wargames

Let's recap a littleSo far we've: Reversed a stringShifted bits left and right (mostly right)Brute forced a known simple cipherFaked it, but then looking for a 4 digit known pinWhat we need next in our toolbox is to be able to search through a large number of values to

Calculating Pi via the Gregory-Leibniz series in BASIC on the VIC-20

Calculating Pi via the Gregory-Leibniz series in BASIC on the VIC-20

It's Pi day tomorrow, and you know what that means! Cherry is favorite. Apple is second favorite. There is a well known and easy to understand method for calculating Pi with the Gregory Leibniz series. Leibniz built on the work on Gregory. It has the added benefit of being pretty

Quick Post: Commodore 64 Simple Addition Efficiency

Quick Post: Commodore 64 Simple Addition Efficiency

There are many hacks you can do in Assembly language on the Commodore. Here's a very easy one with impressive results according to my analog stopwatch. We want to count to $ffffff or 2563 (224) which is 16,777,216 We wont print to the screen to save a lot

c0pperdragon verdict

c0pperdragon verdict

Ahh, the quest for a better Vintage computer picture never ends. I'm having fun with it anyway. Side thought: At what point does a computer cross over from old: no one wants that 2007 Windows tower you built in your basement, to OMG, it's Vintage, let's drive up the eBay