Michael Doornbos - Imapenguin

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

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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.

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Finding the Prodigal Easter Egg inside the Easter Egg on a Commodore 64

If you REALLY want to get into the weeds on how I figured out the Easter Egg(s) inside the Easter Egg on a 35 Year old album on a 35 year old computer then you're in luck! This video is for you! I mention "the original author" in the

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Quick post: Determining length in Commodore Assembly

A common task in our code is to determine the length of something. In this example, let's check the length of a string like "are you keeping up?" In Python, this is crazy easy. #!/usr/bin/env python message = "are you keeping up?" len(message) Python 3In 6510 Assembly, this

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Benchmarking Retro Computers (mostly Commodore) with marginal methods

Just the BASICs, pleaseOur friend in retro @NoelsRetroLab has a simple BASIC benchmarking tool that's fun to use to compare different basic systems execution speed. We're counting jiffies, which is roughly (sometimes very roughly) 1/60th of a second. We're using three variations of this code on the Commodore BASIC

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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

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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

code

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

C64

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

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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

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Making and Breaking Ciphers with a Commodore 64 - Part 4: The PIN Program from Terminator 2

A few minutes into Terminator 2, the young John Connor takes his Atari Portfolio out of his bag and inserts a foil covered card into an ATM machine and proceeds to crack a pin number and steal some cash from an unsuspecting account. This is a movie prop and doesn't

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Making and Breaking Ciphers with a Commodore 64 - Part 3: The Caesar Cipher

Well here we are at part three and it's a lot to pack into one page. Let's build upon what I called the Shift Cipher and implement what is often referred to as the Caesar Cipher, although there is much debate on when this was really first done. The idea

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Making and Breaking Ciphers with Python, er Commodore- Part 2: The Shift Cipher

In Part 1 we did a simple reverse of a string. While simple, these software steps will help build the skills we need going forward in Assembly without feeling like I skipped right to a 300 line after doing a short one. One foot in front of the other and

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Replacing an RF Modulator on a Commodore 64C

The output on my newest Commodore 64 (1989) is pretty marginal. The colors are okay(ish) but the text lines are clearly bleeding and the picture is very muddy. Most vintage computers don't do red text on blue very well, but this one is particularly painful. Red on dark blue

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Making and Breaking Ciphers with Python, er, a Commodore- Part 1: The Reverse Cipher

Sometime during my weeklong exploration of SHA-256 on a Commodore realized that there was a whole world of exploration that could be explored. Just because a Computer system is old, doesn't mean it's not interesting or useful. I had expected it to take months to figure out the SHA-256 implementation,

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Simple, 'unbreakable' encryption with a pencil

Last week, at this bat-time on this bat-channel, I talked about checking off one of my 35 year old bucket list items by learning Commodore assembly language. (shut up, you're old too.) Coincidentally, I picked this up at the time I was re-reading Cryptonomicon by Neal Stephenson for the ump-teenth

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Getting started with Native Commodore 64 Assembly

Some time in the month of September 2020 I dug out the old Commodore 64 that my Dad bought for himself in 1983. It quickly migrated its way into my room and stayed there until 1993 when I joined the Navy. Someone in my family, probably Mom, carefully packed it

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Friday fun: Games I'm playing in Jan 2021

I'm blown away by some modern games still being developed for the Commodore line of computers. Both games I'm playing in January are sold by Protovision, who has probably the best vintage company name on the market right now. Soul Force is an excellent take on a side-scrolling space shooter

linux

Switching to 64 bit Raspbian Linux is a snap

Have you been itching to do 64 Bit ARM assembly program like I have on your Raspberry Pi? I'll bet you have. I mean, the thing has to be useful for SOMETHING right? Most Raspbian installs are still on 32 bits, but switching is easy. Make backups and all that

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Did you do that on real hardware?

People are funny on the internet. We always seem to divide into tribes even when it's not necessary or advantageous to do so. I wasn't surprised to see someone (there's always one isn't there?) comment that I might be using real hardware, but for only part of my retro setups.

Commodore

Merry Christmas

DOS

My #DOScember pick for the best DOS Software

For #doscember my favorite DOS software is STSPlus by the late Dave Ransom. This was a fixture on my computer screen for many years. Still works ;)

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Why does there have to be a why?

It was just a few months ago that I started to get back into 8-Bit computing. It started with Ben Eater’s Breadboard 6502 build. Something about his complete exploration of that build including single stepping the clock and watching the processor registers was really compelling to me. I built

Imapenguin, reborn

I don't remember when I first bought Imapenguin.com. I'm guessing in 1998 or 1999ish. Over the years it was my consulting company and about a decade ago I moved over to doing other things (like Evadot, which is now a "what am I going to do with this next"