Entrants List 2019/03

Listed below are the competitors joining us for the 2019/03 event:

Halftime comments in blue...

Final comments in red...

Rebuttal comments in orange...

John W. Linville



As the event sponsor, it wouldn't be fair to let me win. But, I see no reason why I can't post about my own project! Think of it as the "pace car" for the race...

Anyway, last autumn I was working on a compiler project for a bit. I'll use that as the subject for some blogging while I try to get back to advancing the project during the contest. I'm going to work on a Tandy Color Computer (CoCo) project that enables the use of the CoCo's Game Master Cartridge hardware as a means for playing a variety of "chiptunes". Hopefully that both sets an example and proves entertaining for others. :-)

Well, at least I've managed to do a little writing this time! Not the best effort ever, but give me a break...CoCoFEST! is coming!

Queue the sad "contestant loses" music... Not a great "pace car", but thankfully the group didn't really need me!

Matteo Trevisan (Toolkitman)



I'm entering in this challenge with this new entry, an "AMIGA 500 Mini" built with a plastic made for the occasion Case and a Raspberry pi as core and a dedicated distro installation with a configuration that calcate the most perfect similar AMIGA 500 configuration. I will show it running with some new 2018 AMIGA games in this event.

Lots of posting and apparent progress during the first week, including progress on building a Raspberry Pi emulating an Amiga, a couple of game reviews, and even a new "guess a number" game. But...nothing since 6 March! Are you still working, Matteo?

Apparently Matteo had some pain from a back injury slowing him down -- no one wants that! Anyway, since the halftime report Matteo got a few more Amiga games installed and looking good. Also, this:


It definitely looks like he was having some fun -- isn't that the point?

Mark D. Overholser  (MarkO)



To make this a project that actually can be completed in time, I am "attempting" a Multi-Player, Networked Text Adventure, with a Server running on a modern PC, and the Clients being the Apple ][, ( with the Uthernet II Card ) and the Tandy CoCo, ( with a Serial Port and a Lantronix UDS-10/100/1000 ).

I still have not given up on the Idea of Networked CoCos and Apples and C64/C128s and such..

This is the Year, to make a Showing in The RetroChallange!!!!!!

We see some early signs of progress on Mark's CoCo vs. Apple II networking game, essentially undetailed reports of getting tools set-up for a C language development environment. Then after the first week, the trail goes cold...

I have talked to Mark not too long ago, and I thought there might be some progress to report here. Unfortunately, I'm just not seeing it on the blog. He even had an exhibit at VCF NorthWest entitled "Networked 8-Bit Computers for Gaming, Collaboration and Socializing". Did Mark's packets ever fly? We may never know...

Jeff Piepmeier (jeffpiep)



I plan to build a second prototype of my Atari 8-bit cartridge interface adapter for the ESP8266 WiFi MCU. I have a working rat's nest using an ESP32 and ESP8266, but will change out the ESP32 for an Arduino Nano board. I will make changes based on lesson learned from the first prototype and optimize the timing of the Nano firmware and my custom Atari R: handler. This project contains both modern (MCU's programmed using the Arduino framework) and vintage (an Atari 130XE programmed using MAC/65 assembler) hardware and software. I was inspired by Thomas Cherryholmes and his remarkable PLATOTerm/IRATA.ONLINE project.

Jeff is combining a bit of the new with a bit of the old, working to make a cartridge for Atari 8-bitters to connect to the revived PLATO system. Jeff has a series of well-sized blog posts describing his hardware prototype, some problems, some problem solving, and the solutions. Not yet a done deal, progress still looks pretty good. Hopefully Jeff will have a success by the end of the month.

It sounds like "real life" caught-up with Jeff... Oh, well -- at least he got a neatly dressed breadboard circuit out of the deal.  Overall good blogging -- I hope Jeff had fun!

Michai Ramakers



For this RetroChallenge, I would like to make an info-animation or -demo
for the HomeComputerMuseum in Helmond, NL. I'll effectively continue where
I left off last time (RC2018/09).

This is mostly a code-only effort, where a spare Commodore 64 will be showing an informative animation to passers-by. (The museum is located in a street with a fair amount of pedestrian traffic.)

The animation will consist of simple graphical "demo-style" effects with logo, pictures and informative text about the museum.

Let's consider this effort "finished" when this thing runs at the actual museum, on an actual C64.

Michai starts from a strong base inherited from his previous RetroChallenge project. Unfortunately (like me), Michai seems to have been dragged down by real life concerns. Hopefully this last week of the month will provide Michai with a helpful burst of energy!

Yikes! Another victim of "real life"? Well, it happens to all of us... ;-)

Dustin Johnson (di0)

(Twitter Free)



Compaq's 1st computer, the Compaq Portable I -- well, I'm turning it into a supercomputer, utilizing the stock hardware as a terminal for the cluster UI.

Dustin's blog ends in February... It looks like he got a collection of parts, but I'm not seeing any progress so far...

Still no progress -- apparently supply issues!

[Supplier] hosed me by sending me parts two weeks late, also, I am still working on rebuilding the keyboard (foam pads, ugh). There's no way I can finish this month -- please enter me in the next round!

Tom Raidna



A. Release of a new Programming Language for the Apple IIgs - MUMPS - character based interpreter including tutorial documentation and YouTube training videos.

B. Launching the retro software company I always wanted as a kid - Andiar Software - Wordpress site, Gmail, Twitter to support A. And C.

C. New programming to use the character MUMPS interpreter and take it GUI in GSOS, in a way that greatly simplifies and removes barriers to entry in GSOS GUI development, including interpreted GUI, conversion of resource (.rez) files to mumps code, which will allow use of Design.Master GUI / resource editor use for interpreted “Visual Mumps” and one proof of concept application possibly  a simple RPN calculator or simple database front end.

A new programming language implementation, a GUI toolkit, separate tutorials and documentation on the web, and example apps -- what is not to love?  The blogging is both thorough and entertaining as well. Tom is always a strong RetroChallenge competitor, and this time is definitely no different!

Clearly, Tom followed-through to the end. This is a great project -- even the documentation by itself if noteworthy. A new programming environment for the Apple IIgs in 2019 -- amazing!

Eric Pooch



Finish designing and start building a Kim-1 Simulator card for the Apple IIe

So many "retro folk" people not only have their favorite "mainstream" computer (e.g. Apple II, Commodore 64, ZX Spectrum), but they also have an interest in something older (and/or more weird). For many folks in the 6502 sphere, that older weird thing is the KIM-1. Popular enough in the past to be fairly well known, but old and rare enough to be, well, a lttle rare, offering an obtainable work-alike hosted on an Apple II is a noble goal.

Good use of existing/available tech (e.g. the SuperProto card), good blogging and great construction notes. This is definitely "one to watch".

Oh, no! So close... As the end of the month closed-in, Eric found that his KIM-1 card just wasn't working. He as able to troubleshoot and fix some issues, but it still didn't work at the end of the month. Still, not too bad for a month-long schedule for a first attempt to build an Apple II card. I hope Eric continues this project and makes it available to others as well!

Jim McClanahan



One game I really enjoyed tinkering with "back in the day" was a simple Pong-style game that I typed out of a magazine for my OSI C4P-MF (I believe it was after I had upgraded from the C1P anyway). It was written in BASIC and fairly bare bones which meant two things. First, I could actually understand what each and every line in the program did even though I don't remember it being particularly well commented. Also, with that understanding, I was able to do things like add color and make use of the joystick instead of the keyboard for moving the paddle. That gave me the confidence and experience to move on to bigger and better efforts. Nearly four decades later, I'd like to recreate a simple pong game from scratch, once again using the Color Computer 3 and once again trying to leave a "trail of bread crumbs" that hopefully is useful to others down the road.

Hmmm...well, it looks like Jim has gone back to playing with the  Kolakoski Sequence, this time implemented in Python. Hey, I get it -- a cool, and useful language combined with a geeky, retro, math project. It sounds like it could be fun...

Well, I'm still not really seeing any progress. Failure to launch? Or just DNF? In either case, better luck next time!

Will Cooke

(Twitter Free)


Since this is my first Retrochallenge and since time is what I have the least of, I will start fairly simple.  When I got my second computer, a Commodore VIC-20, in 1983ish, I had grand plans of building robots.  That hasn't happened (yet,) but I still have the VIC-20.  For this Retrochallenge I plan to build a small, simple robot arm that is controlled by that very same VIC-20.  Finally!  After 35+ years my dream may just come true.

A home-built robot arm interfaced to a VIC-20 -- you have my attention!  The pictured build looks like a cross between an Erector set and a steampunk version of The Terminator. I think Will is largely on the right track, but has some family commitments distracting him -- something about priorities... ;-)

It looks like there was no progress since half-time -- too bad, since it looked like a decent start. Will, I hope you had some fun. Maybe we'll see you back again in September?

Brandon Blodget

(Twitter Free)


My goal is to create a way for the TI-99/4a computer to control a "compute cluster".  I have not programmed a TI-99/4a since I was a kid in the 80's. So the first step will be to re-familiarize myself with the machine and research potential solutions.

Brandon starts out by digging-out his old TI-99/4a and doing some web-based research on AtariAge. Quickly he transistions to building an RS-232 upgrade, and playing around with the FinalGROM99 SD-card storage option and an interface to a Raspberry Pi PCB. Lately Brandon has been experimenting with Forth on the TI-99/4a. I'm not sure if Brandon will get to controlling his “compute cluster” this month or not, but it is great to see him geting excited about his TI-99/4a.

It looks like Brandon's project was largely a success. He was able to trick-out his TI-99/4a with some modern upgrades, then use those upgrade to interface with a Raspberry Pi and some sort of FPGA hardware in order to engage in "ClusterFights". Part of his project involved an attempt at building a UART interface, and his final write-up philosophizes a bit on that as well. It's always good to see some introspection after spending so much time on something as arguably ridiculous as RetroChallenge... ;-)

Scott Lawrence



It's either going to be one of these projects, and depending on where things stand at the end of this month (over the next week) as well as where my motivations sit, i'll figure out which and make my intentions known on March 1.

  1. Portable Raspi-Amiga in a Tandy 102 shell - reusing the shell and keyboard from a Tandy 102, using my Amiga keyboard and controller interface, Raspberry Pi 3, and 3.5" display, make a nice portable (emulated) amiga
  2. USB Amiga Floppy Drive interface PCB.  Using an existing project on the net, make a board to hold the components for this.  The project has working firmware using an arduino micro and FTDI interface, but there's a lot of hand-wiring to be done to connect them up and also to a floppy drive connector.
  3. RC2014-TMS9918 Emulation.  There's currently no emulator for the RC2014 Z80 computer that also integrates in the TMS 9918 display chip.  I have plans to expand out that computer and to have emulation of it will make development substantially easier.
  4. RC2014 OS project - Bringing my old pac-man hardware based 4-task switching OS to the RC2014 using the TMS display chip.
Too much noise in my brain. I don't know what to do.  It'll probably be #1 most likely.

It looks like a bit of a slow start from Scott, followed by some excitement and a brain dump on Z80-related emulaton. Apparently with some inspiration from The 8-bit Guy's "Commander X16" 6502 project, Scott might build his own custom neo-retro machine...or emulate one...or something...  Well, I'm pretty sure he is having some fun. Whichever way he goes should be fun to watch. :-)

Well, I'm only seeing the one update. It looks like Scott had plenty to work on, and I hope he had fun -- but no blog means it didn't happen... :-(

Michael Dexter



I have used BSD Unix since 4.3BSD and have FreeBSD working on the bhyve hypervisor back to version 5.0. My project is map out how to support older than 5.0 using a combination of bhyve, Xen, and QEMU, ideally back to 386BSD.

Hmmm...under "March Updates", I see this: "FreeBSD History Rebuild is part of the RetroChallenge 2019/03". But I'm not seeing any details...point me at a blog post?

Still no blog for RC2019/03...

Richard Loxley



In RC2018/04 I tried to restore two Osborne 1 portable computers.  One restoration was completely successful, but with the other I couldn’t narrow down the problem in the disk controller as I lacked sufficient test equipment.

This year I’ll be doing a light-weight entry as I don’t have too much time available.  I have just acquired a logic probe and a 16 channel USB logic analyser.

My plan is:

  1. Install the logic analyser software on my netbook and learn how to use it, and also how to use the logic probe.
  2. Warm up with a couple of dead Video Genie computers (that are quite easy to work on) and see if I can bring them back to life.
  3. If time allows, I’ll move on to the disk controller on the Osborne 1.
Richard calls this a "llight weight" entry...after an intro to his new USB logic analyser,  Richard jumps into fixing one Video Genie, and then another, and three updates working on cassette deck repair. The included videos are no threat to Hollywood, but they are informative and even entertaining, from a certain point of view!

Richard ended-up concentrating on reparing his Video Genie machines. As usual, he does a great job not only in fixing those machines but also in documenting the process both in prose and on video. Richard again demonstrates how to enjoy the true spirit of RetroChallenge. ;-)



Describe and show the ultimate pimping of a 1992 Sun SPARCclassic, and explain the historical background Sun missteps that make doing so neccessary.

Shelldozer's treatise on SPARC updates seems to have been delayed. Maybe he will find time during this last week of March to blast something out. I suspect that there are still plenty of SPARC lovers out there that could benefit. Heck, I almost bought a book on SPARC assembly language just the other day...

Alas, nothing but the initial blog entry... :-(

Raphaël Assenat



In the previous edition (RC2018/09) I learned a bit of SNES programming, but all I did was a controller test ROM.

So for RC2019/03, to avoid forgetting what I managed to learn about 65816 assembly language and SNES architecture, I intend to put my skills to use to create an SNES game, something I've always wanted to do!

I have not decided yet exactly what kind of game it will be, but I would like it to take advantage of the numerous buttons found on the NTT Data Keypad, since there are not enough (or none, if you don't consider JRA PAT a game) games supporting this controller.

Raphaël decided to capitalize on the SNES learning he did for the last RetroChallenge and to use that knowledge to produce a game. I'm sure that more than one of us harbors such a hidden project -- I know that I do. Raphaël then takes us "soup to nuts" on the project, setting-up development tools, choosing the game to implement (Sudoku), discussing hardware quirks and game implementation issues, and even building his own SNES cartridge. This looks like another strong performance from Raphaël so far.

Raphaël shows us an extremely ambitious project around developing a SNES game. Programming, sound design, cartridge PCB design and construction, even building and labeling the plastic cartridge. As an aside, I once did some work on a Sudoku-based cartridge for the Tandy Color Computer. I may need to revisit my project with some inspiration from Raphaël's. Definitely a stand-out this round!

Mark Sherman



I am continuing to work on kittyOS for the RC 2019/03.

Another "soup to nuts" effort, but this time for a custom computer built around an AVR. In this case, we have not only a hardware design but also a custom OS. Mark admits that this stretches the "retro" theme a bit, but it is an ambitious project with a familiar "retro" smell and taste to it. It is good to see such an in-depth project being done just for fun.

Mark makes significant progress, achieving a "two-tier memory system that can automatically swap objects between the very limited internal SRAM of the Atmega MCU, and the external SRAM". Microcontrollers have memory models that are a bit different that "desktop" or "server" processors, so there are some issues here that probably weren't covered in the average undergrad's Comp. Sci. classes. It's good to see that Mark recognized his achievement and moved-on for now -- enjoy the feeling of accomplishment!

Abraham Vreugdenhil



During the RetroChallenge I want to use an IMSC011 Transputer interface chip to controll LED's and read switches. So first the hardware and then the software in the language OCCAM ofcourse. What are the difficulties and issues I find on my way to have control over the Input and the Output of real hardware with the Transputer.

Blinking lights, a homebrew ISA card, a transputer program written in Occam...this project is lit like a Christmas tree (or maybe a Menorah) with RetroChallenge keywords. This isn't everyone's definition of fun. But for those of us that can feel it, we know that only that RetroChallenge kind of fun could be behind a project like this -- inspirational!

Abraham succeeds in his project to build an IO-Link interface around the IMS C011. This is another great RetroChallenge project -- lots of technical ability, some arcane knowlege, a weird goal, and arguably little or no practical benefit to the world. I'm really excited to see this bit of success.




I will do some sort of RC2014 stuff, which might include designing and testing an SD card interface.

I'm not seeing any updates here either. Hopefully there is some other kind of fun brouhaha taking priority this month?

It looks like there was a switch to doing a Z interpreter for SOS on the Apple III, but that effort got stymied by a floppy drive problem. Fixing the drive didn't get a lot of attention until after April started...oh, well -- maybe next time?

qguv and utz





Gameboy audio software hacks, maybe a little graphical demo too

Utz and I will be working to squeeze an additional audio channel out of the original 1989 Nintendo Gameboy using software hacks alone. The system can typically play three tonal voices and one noise channel; we're hoping to achieve four tonal voices, and we might be able to leave the noise channel intact. All in LR35902 assembly >:)

Nice "intro" write-up on the Gameboy audio hardware, how to use it, and how to get more out of it. The Github project has some code in it already, so be sure to take a look. Quint says "it's still easier to write code than prose, so the hackaday project log is somewhat behind the repo". Looks like good progress so far, perhaps with more prose to follow?

Just wanted to let you know that I wrote a bit today about the Gameboy's audio synthesis capabilities and the reasons you'd want to fiddle around with additional channels in software.


We've achieved six (!) software audio channels, and I think we can squeeze one more out of the wave channel for a total of seven! But it's still easier to write code than prose, so the hackaday project log is somewhat behind the repo.

Great write-up, lots of detail, cools toys, nice pictures -- definitely some great work here. After reading the stuff at the URL above, I think I have a slight headache, and my nose is bleeding...but I'll be fine...eventually... ;-) But seriously, definitely some good work on a cool retro platform.

Stephen Barriball (z0m8ied0g)



Going to play with my MicroVAX 3100 and try to install OpenVMS.

Not a lot of visible progress so far. Hopefully Stephen's "mini retro enthusiast" project will deliver an awesome playmate next month, if not before. Best of luck in any case! But if you do find some Vax time then let us know -- OK?

Did I miss the Vax backup woes earlier? From the blog entry dates, I must have. Anyway, at least Stephen did get some Vax time, but his tape system let him down. I can't blame him for wanting a backup before he potentially wipes the system! Hopefully he'll find a replacement tape system or a way to repair what he has now.

Jim Gerrie (jgerrie)

(Twitter Free)


My usual. Working on porting some programs to the MC-10. Type-in's mostly:
  • Cheese
  • Mushroom Invasion
  • Convoy
Will try to blog about them and some of my other recent projects.

Jim Gerrie -- the hero of the MC-10. I am always amazed at what Jim produces for that little oddball machine, especially since he never stops. On The CoCo Crew Podcast, we have taken to ringing a bell every time we mention Jim's name -- no kidding! Jim's Manic Miner is looking good, BTW...

Jim continues to constantly crank-out creations for the MC-10. It was really cool to see Manic Miner ported, especially to the "semi-graphics" mode. His other games (including Convoy) all look top-notch as well. Really, we need to get Jim at CoCoFEST! for proper adoration from his fans! But in any case, "good job" on RC2019/03. :-)

Marcel van Kervinck



The Gigatron is a single-board 8-bit TTL computer without microprocessor. It can run video games and BASIC. What is still lacking, is more I/O. Much more I/O. There objective is expanding the computer with four SPI interfaces, so that it can access MicroSD cards, IoT gadgets or up to 64 GPIO pins using the popular MCP23S17 port expander chips. The challenge is to stop thinking about this and to start building a working prototype on a breadboard or PCB, including proof-of-concept software for at least controlling an array of LEDs.

A standout in the world of oddball retro projects, The Gigatron is truly some amazing work. This month's project seems to be focused on add-ons, and they certainly seem to have made some good progress so far. It is truly amazing what a few people motivated by talent, retro nostalgia, and a little weirdness can do. My only question is, will this one "go pro" on Tindie?

I’m collecting feedback from VCF PNW 2019 <https://hackaday.io/project/164176-gigatron-io-and-ram-expander/log/160942-vcf-inspiration> so I brought the expander there….

[We’re not on Tindie (yet), but one guy flew over from Alaska to get a Gigatron kit… That works for us...]

It is great to see this project's continued overall progress. This is definitely in the RetroChallenge "because I can" mold of thinking. I doubt we will ever see a line of people trying to get these through the TSA lines at the airport, but I wouldn't be surprised if this became a common sight on the workbenches of a variety of "tinkerers of a certain age". In fact, that could be kinda cool... ;-)


What a great group of projects. Despite the usual few derailed by distractions, supply issues, etc, we still got some really cool successes and a few that were hopefully at least worthwhile to the competitors and the readers. With the basic reviewing/commenting done, I'll need another day or two to name winners and such. If you have an opinion on that, then feel free to comment below!

Otherwise, we'll see you in September for RC2019/09...


  1. Hi @Toolkitman, thanks for joining in once again. Is there any way I could read your blog without a Facbook-account? Because I have none. Thx.

    1. I have made public it! i hope you can see it let me know!!! Ciao

    2. Thank you - but I still can't access it. But if it works for everyone else, I guess I'll find a way.

    3. I don't do facebook either and I can't see it either.

  2. This comment has been removed by the author.

  3. uhm i think you need a Facebook account at least! : )

  4. Hello, I didn't get into the entrants list, but I have finished my project, in time for April Fools'. https://github.com/olsone/games/wiki/9d9damashi-RetroChallenge-2019-Blog

    It is a mashup of TI-99/4A MunchMan and other games with 2004's Katamari Damacy. It runs on a TI-99/4A with 32k memory expansion.