Thursday, August 20, 2020

2020/04-05 Results!

First, I would like to appologize to everyone for taking so long to write up these results.  The world is in such a crazy state right now, I am have able to barely keep up with the things I need to do.  I hope you all understand, and I wish you all good health.

I encourage everyone to keep working on their projects when they have the time.  And, feel free to re-enter an existing project for a future retrochallenge... as long as there is new progress to be made.

Thanks everyone!  Stay safe.

Best Hardware

Just4Fun : : V20-MBC a computer that supports 8080 and 8088 code.  Very interesting and challenging project, with good documentation.  It looks like anyone can just download the files and build their own!

Best Software

Paul Robson :  Homebrew microcomputer named Eris with graphics and a few games.  I'm putting this is the software category, because the computer existed prior to the retrochallenge... This retrochallenge was about programming it for graphics and games.


Decle : : Accessing the hidden debugger baked into a videogame cartridge.

Honorable mentions:

Matteo Trevisan : : TINA chatbot. When I started this retrochallenge 'unofficially,' I put a theme up of time travel.  Matteo delivered on this, and created an Eliza-themed chatbot, with some custom hardware.  The chatbot is also emulatable in a web browser, and is embedded on

Raphael Assenat : : first time MSX user.  He does a good overview of the MSX computer, how to set it up, hardware pics.  Anyone who is considering getting into MSX, might want to read this page to familiarize themselves with the system.

Jim Gerrie : : He is a very prolific author of MC-10 software, and delivers good documentation.

Biggest Tease:

Eric Smith (COSMAC ELF)
This project looked very promising, and had a good photo gallery, but despite a few emails by me, his website is not up and running.  I'm also interested in COSMAC computers myself, and one of my previous entries to the retrochallenge was the 'COSMAC ORC.'  I really wanted to see what was going on here.  I guess, with the photos, I did get to see what was going on, but I really wanted to read the details.  And that's why this project was a big tease.

Tuesday, June 2, 2020

Time's Up

I hope you all had fun with this distraction.  I'll be looking at all the entries in detail soon.  Apologies if it takes a little while... I have a lot of crazy things going on right now, we all do.

Monday, May 25, 2020

Last Week

There's one week left.  If you don't like your picture, summary, the link is broken, or I somehow missed your entry, please let me know.  Good luck everyone!

Send any missing entries or comments to m at mwsherman dot com

Friday, May 15, 2020

Third Quarter Report

There are about two weeks left, so I wanted to say a few things about the projects I've been watching.  I've broken them up in to a few categories.

Homebrew Computers

Building your own computer... starting with chips.

Eric Smith (COSMAC ELF) (blog) (photo album)
His website is still not working, but there is a photo gallery.  It seems he has constructed several COSMAC ELF front panels.  I hope he gets his site running soon, as I have built an ELF before, and want to see what he does with it.

Paul Robson: (Eris computer)
An amazing entry.  This is writing games for a homemade computer system called Eris based off an ESP32.  The amount of work needed to create your own platform, and then make use of it is not to be trivialized.

Scott Baker: (z80 FPGA)A Z80 in an FPGA. Scott Baker (forum blog)  (Github)  It seems to be working great, its even running Conways Game of Life.  (On a sad note, John Conway has recently passed away from COVID-19... The world has lost an interesting mind.)

Just4Fun (V20/8088 SBC) (link) They are building a single board computer that works either with in 8088 or a V20 CPU.  Best as I can tell, the V20 is a faster 8088 that also has a build in 8080 emulation mode.  This is interesting, as it is essentially two computers in one.

Retro Coding

Writing programs for old platforms.

Jim Gerrie (MC-10 gaming) (link):
Jim never dissapoints... His devotion and dedication to the MC-10... a system most prople ignore is incredible.  This system is seriously lacking in power compared to its big brother, the CoCo, but the creativity involved to make working adventure games on this platform is something to see.

Mark Wickens (VAX Projects):(link) Successfully porter lunar lander to an emulated VAX.  This is pretty cool.

Matteo Trevisan (Chatbot): (link)  A chatbot loosely based on ELIZA for early Apple computers.  This is double-retro... A 1960's program adapted for a 1980's computer.

Pim van Tend:  (Forth on HP) (link)
Pim had a previous project where he got Forth working on an HP simulator.  This time around, he is expanding it from a limited Forth to Forth-77.

Decle : Accessing hidden debugger built into World Championship Baseball for Intellivision.  (

Retro Platform

Getting to know an older system, setup and possible repair.

Beniamino Cenci Goga:  (playing with old Apple computers)
This one is interesting to me because its around old Macs.  I never did much with Apple computers, but we had them in school when I was a kid, so it is a bit nostalgic for me.  Reading thru his progress, it makes we want to pick up an old Mac and play around.

Raphael Assenat (First time MSX User) (
 An impressive demo of what the MSX can do.  I picked up a MSX on ebay about a year ago, but never did much with it.  Included are hacks on getting TAP images into real hardware without a real tape... I'll need to do this soon.

Richard Loxley (Osborne 1 repair) (
Richard is making a second attempt at fixing a pair of broken Osborne computers.  Not much progess has been written yet, but I hope there is an update soon to read.  Interestingly, the Osbourne computers were build in my hometown of Hayward, CA.


Taking a premade single board computer, and building it into a working system.

Abraham Vreugdenhil (Z80 SBC Program Loader) (
He is building a little hardware necessary to load programs onto an old Z80 single board computer, the MPF-1b. 

Eric Pooch (CMS 9619A SBC running OS9) (
Another program-a-raw-SBC-board project.  Eric has gotten the OS9 shell running on a  9619.


Simulating old hardware the best we can.

Tobias Langhoff (Dream 6800 Emulator) (

Latest update... He is learning 6800 assembly language.  Earlier, he already had some games running in the emulator.

Jeff Salzman (MOBIDIC  simulator) (
Jeff is continuing a previous project to emulate a MOBIDIC computer.  The MOBIDIC is an early "portable" computer, from when portable meant a whole truck trailer.


Please update your blogs... I want to see what you are doing.

Mark Overholser  (Apple ][ Projects)

Niels Mosele (Unknown Project)

Thursday, May 14, 2020

Two weeks left!

There are still 2 weeks in the retrochallenge!  I have updated the entries page with everything I have seen so far... If there is a broken link, you don't like the picture, or I somehow missed your entry, please let me know.  It's also not too late to enter...  Happy coding / soldering!

Monday, April 6, 2020

RetroChallenge 2020/04

Hi everyone!  I've like to thank John and Michael for running previous Retrochallenge events.  I started this on unofficially as the RetroChallengeRetry, and much to my surprise, I have been welcomed to make it official!  I started under a different set of rules, but similar to this retrochallenge.  You can conform to either the traditional retrochallenge rules in the top link above, OR the rules listed on

-Mark Sherman

Extended thru the end of May 2020!



Send entries to m at mwsherman dot com. Subject line: ( RC2020)
The intention is a friendly competition where everyone can follow each other's blogs and watch progress. Don't wait until the last minute to send your link... or we will all be bored.