Blog · corpus.blog/blogs/michaeldoornbos.com/posts
michaeldoornbos.com
michaeldoornbos.com
2021
Been working on a magic square solver for a couple weeks now. My recursive backtracker in Python typically takes about 290 tries. Iterative approach on the PET I've got down under 100 tries (although it takes 15 minutes). Pretty happy with this. #commodoreoriginal ↗
5 Dec 2021
Used my favorite VIC-20 for #AdventOfCode Day 3. Did need to use a RAM expander on the lowly VIC, but it worked out okay. #commodoreoriginal ↗
3 Dec 2021
For the #AdventOfCode Day 2 Part 2 my 8 Bit platform is short a single digit to display the precise 2 billion+ answer (intentionally blurred). So my 1983 Tandy PC-4 got recruited for the assist. I’m counting this as fair play. #commodore #PEToriginal ↗
2 Dec 2021
Blurred my answers ;-) Weapon of choice for #AdventOfCode Day 2 is the #commodore #PET #AdventOfCode2021original ↗
2 Dec 2021
The two best Christmas albums of all time. We have many, many albums and these two are the best.original ↗
1 Dec 2021
The #AdventOfCode Day 1 part 2 was a three-measurement sliding window. See, who needs more than 8 Bits in a computer? I blurred the answer, no cheating ;-) Url if you want to participate is: https://adventofcode.com/ #commodore #C64original ↗
1 Dec 2021
Doing the #AdventOfCode for December using my weapon of choice. Day 1 part 1 was a snap. If I don't print the lines (looks cooler if I do) it gets the correct answer in 31 seconds. Not bad for a 39 year old machine #commodore #c64original ↗
1 Dec 2021
Today's learn something every day: Back implementing manual stack and memoization on systems that don't REALLY do recursion. To help visualize loops, I started printing the status on every loop on a delay and reversing the stack pointer digit so I could follow it. #commodoreoriginal ↗
30 Nov 2021
29 Nov 2021
Today's "learn something every day": Been studying recursion implementations in modern languages like Python. Taking this back to 8 Bit machines...this is the first time I've ever studied implementing a manual push/pop stack pointer combined with memoization. Got a lot of uses to ponder for this. #commodore #VIC20 #pythonoriginal ↗
27 Nov 2021
Back to noodling during lunch with the "AI" computer player algorithm for this "connect five" game which I can still pretty handily beat. #commodore #appleIIoriginal ↗
24 Nov 2021
Apparently it’s Fibonacci day (who makes up these days). Anyway, seems like a fun job for my crazy slow 1991 Sharp 9300C Hat tip to Andy Anderson for bringing this to my attention #FibonacciDayoriginal ↗
23 Nov 2021
This took me a while to figure out: All permutations of a naturally ordered string. In Python/Rust I'd use recursion, but on an 8-Bit you run out of space on the stack pretty quickly. Managed to come up with a working iterative version. Now I'll redo it in Assembly ;-) #commodoreoriginal ↗
23 Nov 2021
Writing some weighted depth first searches for some security software in my day job. Can't think of a better way to refresh my tree searches knowledge than doing it on a PET. #commodoreoriginal ↗
21 Nov 2021
I’ve never cared for the 80 Column hacks for the Commodore 64, but I love the Mandelbrot PETSCII program on the PET 8032 so much I could not resist. On this weeks episode of “Stupid Races Between Old Computery Things" PET vs C64(80 columns) vs 128 (10x speed) #commodoreoriginal ↗
20 Nov 2021
I acquired this white TI nspire today. It’s disqualified from being on my episodes of “Stupid Races between old computery things” because it’s not old and with an ARM9 @ 396 MHz is more like a baby Raspberry Pi than a calculator. Still will be fun though.original ↗
19 Nov 2021
I'm always looking for something to do with an 80 Column PET. Mandelbrot in PETSCII might be cooler than any high res versions I've seen. Real-time took about 13 mins. #commodore #mathisfunoriginal ↗
18 Nov 2021
Barnsley Fern on Apple IIe, Commodore 64, and TI-84. The 8-bit machine videos are sped up 300% to match the much faster calculator render speed so they complete at similar times. This was VERY satisfying to do. #TI #commodore #appleIIeoriginal ↗
17 Nov 2021
I think today's learn something every day is going to be to take this Apple II Barnsley Fern (sped up) and port it to a #commodoreoriginal ↗
17 Nov 2021
What? I'm just sitting here thinking about how to best do recursive backtracking in BASIC... #commodoreoriginal ↗
15 Nov 2021
I’ve had a train under our tree for 20 years. Caleb is moving to Texas right after the holidays so it seemed like a good idea to get him his own so he can start his own traditions. We happen to have two trees this year so…original ↗
13 Nov 2021
13 Nov 2021
I do this same walk loop every weekday I work from home. Typically after lunch. It’s 3.26 miles. Just a couple shots from today as the leaves are really starting to turn now.original ↗
11 Nov 2021
I have hunted for and acquired a lot of wonderful vintage technology pieces over the last year. This is easily my favorite of them. I use it every single day. 1962 was a good year for these.original ↗
11 Nov 2021
What the hell? Did they use MT RAM? Another thing I really wish I hadn’t spent money on this year. Arg.original ↗
9 Nov 2021
The amateur mathematician in me has to believe that there’s an excellent chance that I’m the only person on the planet doing #NaNoWriMo21 on a Commodore Plus/4. Living dangerously:)original ↗
9 Nov 2021
Doing some AT backpacking this week. This is what the vertical looks like in the section we'll be on ;-) It's brutal #commodoreoriginal ↗
8 Nov 2021
With very little help from me, young guy I'm tutoring in math took this C64 book listing he found and "ported" it to his VIC-20 including sound. Pretty soon he wont need me. Awesome sauce. #commodoreoriginal ↗
8 Nov 2021
Well @8BitShowAndTell I finally found my original C64 Pac-Man cartridge. Can confirm it has that same title screen bug. I did find one online that someone fixed. Well at least they fixed the fruit anyway. Put that version on my UltimateII+ #commodoreoriginal ↗
8 Nov 2021
A young person asked me to help him port this to the VIC-20 so he can play it. I'm aware of a port already, but if we actually do the port together there's more opportunity to learn so we're gonna do that. #commodoreoriginal ↗
8 Nov 2021
Very happy with progress this morning. So good to be back at this. Tail is back on it, closer to being permanently mounted. That skin on the front is going to need a fair amount of trimming next. #myzenith750original ↗
6 Nov 2021
Was making a plaque on the CNC for my “wall of shame” to showcase stuff I’ve screwed up on this plane build. How’s setting the depth incorrectly and slamming the router head into it for irony? Scratch one plaque and expensive bit. Pro Tip: Screwing up is just learning.original ↗
6 Nov 2021
Today is the first of 9 days off in a row for me. Despite the fact that it’s still dark out and 43 degrees (F) inside the hangar, gonna route some fuel and brake lines. #myzenith750original ↗
6 Nov 2021
On a tip from @NoelsRetroLab I found these ROM adapter boards. Picked @PCBWay to manufacture 10 of them to me. I'm still blown away that they can make these and have them at my front door all the way to the US in 6 days. Incredible.original ↗
5 Nov 2021
This morning's "learn something every day" is some polar plotting. R=1+2*COS(Z), pretty neat patterns from this one #commodore #c64original ↗
5 Nov 2021
I love these equation plots. A little lunchtime fun today to relax. This one only took 16 minutes to render, faster than I anticipated. #commodore #c64original ↗
4 Nov 2021
Anyone aware of a scan of this book online? I see some others by him, but not this one. I just copied the Floppy to a disk image. Could scan it easily since it’s spiral bound. #commodoreoriginal ↗
4 Nov 2021
Since I was scolded for taking out the Plus/4 yesterday, I figured I might as well fully get in trouble by powering it on and having it do something. #commodoreoriginal ↗
4 Nov 2021
3 Nov 2021
The road to our house… At some point recently I had realized I have everything I dreamed about 15 years ago. I wonder what our next adventure will be.original ↗
2 Nov 2021
1 Nov 2021
Same Sierpiński's Carpet program but with PETSCII instead of graphics. This is a job for a PET! (2x speed) #commodore #PEToberoriginal ↗
29 Oct 2021
Sierpiński carpet on the Apple IIe took 3 1/2 hours. Here sped up A LOT. Machine language version is next and should be WAAY faster #appleiioriginal ↗
29 Oct 2021
I’m doing #NaNoWriMo for sure, but looking for another thing in November to also dig deep on. I’m thinking about mashing these two concepts.original ↗
28 Oct 2021
I LOVED @Ayliean's Tower of Hanoi video on @numberphile this week. I wanted to try it with some "soothing" sounds from the 80s with the SID from a Commodore 64 #commodore #c64 (sound on!)original ↗
28 Oct 2021
27 Oct 2021
I just picked up this 386 laptop from a guy up the road from me. New in the box. I literally cut the plastic from the factory on itoriginal ↗
26 Oct 2021
TI-81 Screen pixel issue was a manageable repair. Took just a couple minutes. Reflowed the solder on all of the ribbon cables with the hot air station. She's all set for 30 more years of mathing.original ↗
25 Oct 2021
Well this is sad. My TI-81 has developed a column of dead pixels. I wonder if I can replace the LCD.original ↗
25 Oct 2021
23 Oct 2021
A little lunchtime fun: I have my Commodore PET Tic-Tac-Toe "AI" playing against itself with about a 95% tie rate. A couple more tweaks and I think I can get it to 100%. #PETober #commodoreoriginal ↗
20 Oct 2021
Started wearing a 30 pound weight vest on my daily lunchtime hike. Feels really good. Also I think this is the longest my hair has been since 1992.original ↗
19 Oct 2021
A week diving deeper with the PET day 1(take 2): I stand corrected, the COMMODORE PET is a graphics powerhouse. Better graphics than any other computer invented since 1977. #commodore #PEToberoriginal ↗
18 Oct 2021
Have had a great week with the Atari 800XL and then another with the VIC20. This week my choices are:original ↗
18 Oct 2021
You know the boat electrical repairs are getting serious when the bench power supply gets moved in.original ↗
17 Oct 2021
Wrapping up a week with the VIC: Unexpanded VIC with a keyboard version of Breakout. Getting a fair amount of help from machine language here, but it's a very playable (and simple to code/understand) version. LOVED this week with the VIC and appreciate it even more! #VICtoberoriginal ↗
17 Oct 2021
A week diving deeper with the VIC-20 day 6: Pretty much the best graphics of any computer ever made. #VICtoberoriginal ↗
16 Oct 2021
Got an Apple II 80 col/64k expansion card failing a RAM diagnostic. I have at least 4 testers for this type of RAM and plenty of spares.original ↗
15 Oct 2021
A week diving deeper with the VIC-20 day 5: Smooth scrolling isn't too hard. Getting close to the end of my week with the VIC and I appreciate it even more than I did when I started. #VICtoberoriginal ↗
15 Oct 2021
10 minute lunch break "learn something": More of the "AI" book - Breadth first searches are nice and zippy. Apple IIe for this oneoriginal ↗
14 Oct 2021
A week diving deeper with the VIC-20 day 4: The VIC-20 is a graphics powerhouse ;-) #VICtoberoriginal ↗
14 Oct 2021
On today's episode of stupid races between old computery things: A brute force tree solver on a Commodore 128 in 80 column mode vs a VIC-20. The 128 is easier to visualize what it's doing, but as expected, WAY slower. #commodore #VICtoberoriginal ↗
13 Oct 2021
A week diving deeper with the VIC-20 day 3: While not as visually interesting, implementing tree searches to solve shortest path problems is fun for my brain, just maybe not your eyeballs. #VICtoberoriginal ↗
13 Oct 2021
I figured out the problem with my MiniPET/SD card access. This connector is already not making good contact. Going to work on a way to extend the base of my setup so that it’s not just hanging off the end. Or maybe just put feet on it. #commodoreoriginal ↗
13 Oct 2021
This is a REALLY excellent book. I’ve been going through this a chapter at a time. Very little changes to get the code to work on Commodore machines too although I’ve mostly been using the Apple IIe. Great primer to modern AI techniques if you can believe that. I give it an 11/10original ↗
12 Oct 2021
A week diving deeper with the VIC-20 day 2: Some people say the VIC is underpowered and you can't do interesting things with just a couple k of RAM. Whatever slackers! #VICtober #commodoreoriginal ↗
12 Oct 2021
For those who say "3583 bytes isn't enough to do anything useful", a decent cipher fits with 58 whole bytes free. Take that!original ↗
11 Oct 2021
A week diving deeper with the VIC-20: Starting the week finishing up the VIC Cipher on an unexpanded VIC. It's not fast, but it's fast enough to be useful. One of the few of these I've done that's 100% in BASIC #commodoreoriginal ↗
11 Oct 2021
Since my MiniPET is down I’m shifting gears this week. This is one of my favorites anyway so I’m already looking forward to it.original ↗
10 Oct 2021
Working on an old boat today. Just pulled these off of the deep cycle battery. Both red. One was on the positive and one was on the negative. They run under the floor… and the wire chasing begins because the colors sure aren’t right and they aren’t labeled.original ↗
10 Oct 2021
A week diving deeper - PET: Cramming code into single lines isn't just for Perl programmers. Here are two one-line subroutines to convert hex to decimal and back. Hint: you have to use the shortened keywords to get them to fit in 80 columns #PETober #commodoreoriginal ↗
9 Oct 2021
A week diving deeper with the PET: Since I have a fair amount of Commodore experience, seemed prudent to think about and work on text screen program UI concepts. A loan calculator is even a useful one to have on disk in 2021. #PETober #commodoreoriginal ↗
8 Oct 2021
My week with the Atari 800XL is over. I’m writing up my thoughts and some things I learned. In the meantime, this one is next. #octaci #PEToberoriginal ↗
7 Oct 2021
Was just thinking “it’s 3pm and I’ve been super productive today, I wonder why…”. Oh right, that’s why.original ↗
6 Oct 2021
Diving into Atari 8 Bit: Horizontal movement is pretty straightforward. Vertical is a little more tricky. Using an ML program and calling it via USR() makes it MUCH faster. Still having fun(ish). #octarioriginal ↗
6 Oct 2021
This chip is still on my desk. Even though I’m one of the people who has the thermal printer it goes in. The mystery was cooler than the reality. #commodoreoriginal ↗
6 Oct 2021
Diving into Atari 8 Bit: XIO is completely new to me. Combined with joystick inputs to draw a "road". Pretty fun. #octarioriginal ↗
5 Oct 2021
Diving into Atari 8 Bit: More graphics learning and using TRAP which is very nice. Pretty impressed at how well graphics work even in BASIC. #octarioriginal ↗
5 Oct 2021
Diving into Atari 8 Bit: I'm actually off today, but always 5 minutes to learn something. Quick color and plotting. Atari BASIC makes this stuff really easy. #octarioriginal ↗
4 Oct 2021
Diving into Atari 8 Bit: Getting a handle on CTIA chip capabilities. Shading is a pretty cool feature #octarioriginal ↗
3 Oct 2021
Diving into Atari 8 Bit: Reading joysticks is really easy, and Atari BASIC is good enough to make joystick movements smooth in BASIC. Neato #octarioriginal ↗
2 Oct 2021
A little lunchtime fun: revisiting this old maze listing to see if we can get it to be just a little more random. Atari BASIC sure is slow #octarioriginal ↗
1 Oct 2021
The 3.10a Firmware update for the Ultimate II+ seems to have resolved my long time C128 disk access errors on this particular machine. Neato. #commodoreoriginal ↗
29 Sept 2021
Test fitting the instrument panel trays. I may have found an actual use for TheC64 Mini. #commodoreoriginal ↗
28 Sept 2021
27 Sept 2021
In today’s episode of “stupid races between old computery things”: Apple IIe (128k RAM) vs unexpanded VIC-20 with a boring version of the 100 doors problem. Almost identical performance since they have the same processor running a very similar clock speeds. #commodore #appleoriginal ↗
27 Sept 2021
Here’s what the Apple II external power supply installation looks like. It’s dramatically cooler inside the case now and no Rifa caps to explode. Even still worksoriginal ↗
27 Sept 2021