Mike Kohn
mikekohn.net · Personal blog · on HN since 2010
Mike Kohn writes about hobby projects in microcontrollers, retro consoles, assemblers, and running Java on old hardware.
What HN saysHN links it for Java Grinder, which translates a subset of Java bytecode to machine code for platforms like the Amiga, Sega Genesis, and C64.
24HN people shared it
6linked it in comments
27stories submitted
776story points
10 months agolast shared
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Most-shared posts
- 1Java Grinder Outputs Native Assembly for Sega Genesis, Commodore 64, Apple IIgs4 people · 4 points · first shared 2015 · discussion on HN
- 2Amiga Java2 people · 159 points · first shared 2020 · 67 comments on HN
- 3IP over Lasers2 people · 130 points · first shared 2025 · 80 comments on HN
- 4Java on Playstation 22 people · 101 points · first shared 2018 · 22 comments on HN
- 5Hungry Hungry Hippos Autoplay (2017)2 people · 22 points · first shared 2017 · 13 comments on HN
- 6Open-sourced assembler/disassembler/simulator for MSP430 microcontrollers2 people · 11 points · first shared 2010 · 3 comments on HN
- 7PANCAKE-ROM2 people · 7 points · first shared 2017 · discussion on HN
- 8Glow in the Dark Memory2 people · 4 points · first shared 2022 · discussion on HN
- 9RISC-V Implemented in FPGA2 people · 2 points · first shared 2024 · discussion on HN
- 10Tin Can Phone Modem1 people · 139 points · first shared 2020 · 14 comments on HN
- 11Modern 65021 people · 104 points · first shared 2025 · 10 comments on HN
- 12W65C832 in an FPGA1 people · 74 points · first shared 2025 · 12 comments on HN
- 13Cloud RAM1 people · 4 points · first shared 2026 · discussion on HN
- 14Intellivision Java1 people · 4 points · first shared 2021 · discussion on HN
- 15Electric Cat Fight1 people · 3 points · first shared 2018 · discussion on HN
What HN people wrote when they linked it
self_awareness · 2025-11-20
Well, there was also Java on Amiga project:
https://www.mikekohn.net/micro/amiga_java.php
sargstuff · 2024-01-19
Any specific area?
Grace Hopper via Cobol, C programming language, unix, bsd, telnet, uucp/news groups/email, xerox alto, Allan Kay via smalltalk, linux, sequel/postgres, gmail/aol/yahoo, AI (chatgpt), video/hardware emulation with or/without VM layer[3]. software defined radio, open broadcaster software[0], etc.
SpaceX spacecraft total software control panel[1] (vs. apollo phsycial wired switches/buttons )
snarky-> spacex 'soft/flexibile' space suit. Does this snarky concept open the way to 'soft' 3d printed stuff, as long as it's "wearable"?[2] aka astronaut carrying compressed soft origami chair/table.
[0] obs : https://obsproject.com/
[1] : https://news.ycombinator.com/item?id=27115372
[2] : risc-v on FPGA : https://news.ycombinator.com/item?id=39050580
[3] : https://www.mikekohn.net/micro/riscv_fpga.php
sehugg · 2018-02-23
More information and example output here: http://www.mikekohn.net/micro/java_grinder.php
Note that it's just a subset of the bytecode spec (no GC, objects, virtual methods) but might be a nice way to get up to speed on a CPU architecture. I used the SDCC C compiler similarly to learn Z80.
Rjevski · 2017-08-03
Java on Sega Genesis/MegaDrive: https://www.mikekohn.net/micro/sega_genesis_java.php
aninteger · 2015-09-18
There's also javagrinder https://www.mikekohn.net/micro/java_grinder.php which can run some java code on the TI-99/4a, C64, and Sega Genesis by translation of java class files to equivalent platform machine code.
jodoherty · 2012-05-08
Why not just start with some embedded development then?
8-bit PIC and AVR microcontrollers have very simple instruction sets and can be connected to simple I/O devices like switches and LEDs, but they both use Harvard architectures, so you have different address spaces for code and data. The newer 32-bit PIC micros use a MIPS core, but the development tools aren't very open, despite being based on GCC.
The 16-bit MSP430 is fairly simple, has good open-source development tools, cheap development hardware (check out the Launchpad), and a more conventional von-Neumann architecture. Check out some of Michael Kohn's sample code for the msp430 assembler he wrote:
http://www.mikekohn.net/micro/naken430asm_msp430_assembler.php