What os for a retro like raspberry pi?


New Member
May 19, 2019
The raspberry pi is a great computer but it is definitively a modern computer. Most people run Raspbian on it but it is not retro at all. I mean it is a very complex multi task operating system not something like the 8 bits system. Obviously I could run an emulation but I could run an emulation on any pc or mac. What i would like is to have a minimalist (easy to understand) operating system that would run on the Raspberry pi.

I have tried to write baremetal code but the lack of documentation on the gpu and the usb makes this quite complex / limited.

Hence my question: is there an simple monotask operating system (with some graphics output) available for the Raspberry pi.

Note : may be I should try RISCos but it seems a bit obsolete and without an active community


New Member
May 22, 2019
RISC OS is pretty much the only option as It the only OS for the Rasberry Pi designed in a simular fashion as 8-bit systems were in and in the Raspberry Pi native ARM machine code. (Designed for particular machines using the first ARM processors in the late 80's)

The switch off / switch on experience is simular to for example a C64.

It is obsolete like the 8-bit systems but documentation and community can be found at https://www.riscosopen.org/
At the forum please ignore the 'why?' and 'Should you not better do this other thing?' comments from certain trolls that mean well but would suck your energy. There is lots of documentation still available in the original form, even with updated content but also in (less retro) digital format.

Press F12 and you're in a monotask operating system with BASIC available. 8-bit Acorn compatible BBC BASIC and for the full retro experience you can still order a manual in book form at mentioned website! Also from the multi tasking environment it is possible to start your monotask program and freeze the computer as the multitasking is coöperatieve multitesking (A task is run while other tasks are in system routines doing IO).

It runs on a single core without support for onboard Wifi. Accessing RP hardware ports probably doesn't have support in the OS and should be done in machine code but as a machine code compiler is included in BASIC it is easy to experiment with machine code in the BASIC environment.

There is a cut down version "that boots into BASIC for that genuine retro computing experience!": RC5 RISC OS pico.
Last edited:
May 22, 2019
You can also install PC-BASIC, which is an implementation of Microsoft BASIC in Python. It uses SDL for graphics, so you get all of the graphics modes available on the original. The only downside is that you're still limited to 64K of RAM.

In my copious free time (sarcasm there), I'm working on a BASIC interpreter that will look a bit like Quick BASIC. It's going to be a little different than standard BASIC systems, with a full screen text editor and no line numbers. I've already got a code translator going to translate this dialect to PC-BASIC, Commodore BASIC, and BASIC-80 (the BASIC that shipped with CP/M.)

You might also enjoy emulators like RunCPM, which is an implementation of CP/M and Z-80 emulator rolled into one. It's the fastest and easiest way to run CP/M software on a modern PC, since the BIOS is implemented in native code (not Z80 code) and it can work directly with files on your PC.