M/PC – A Concatenative OS

M/PC, a concatenative operating system for the Varvara computer, has been released, inspired by Openfirmware and designed to manage files without a file browser. The OS uses postfix notation and can be navigated with a keyboard or controller, supporting file operations, screen drawing, and ROM execution. It aims to provide a minimal, keyboard-driven interface for file management and application launching.

•/PC M/PC is a concatenative concatenative.html operating system for Varvara varvara.html , inspired by Openfirmware https://en.wikipedia.org/wiki/Open Firmware , designed to manage files on system without a file browser. It uses the postfix notation, meaning that the function success their operands: Get the number of bytes in folder/file name folder/ file name cat len dec Files can store reusable sequences of commands, the tilde prefix includes the content of the file: Content of ./show-slide slide swp cat 3cx22.icn cat 1 icn 1 ~show-slide The interface uses a single prompt at the top of the screen to input commands: Controls The operating system can be used largely without a keyboard to navigate folders and launch roms: left/right Navigate Stack up/down Scroll Stack A Evaluate Selected Symbol B Directory/Back Kiosk To start M/PC as a BIOS rom so that when the user presses F4 , Varvara returns to the BIOS instead of triggering a reboot, launch with arguments: uxnemu m pc.rom orca.rom run Wallpaper On boot, M/PC will try and draw an ICN file icn format.html named wallpaperWWxHH.icn, where WW is the width of the screen divided by 8 in hexadecimal, and HH the height. Reference Here is the list of all primitives: dir -- f Put the file names in the current location on the stack. mov path -- f Move the current location to current/path, then do dir. now -- date time Puts the date Tue, 23 Jun 2026, and time 11:48:45 on the stack. run f.rom -- ok Run the rom file, return with F4. icn f.icn blend -- ok Draw an icn file with blend. txt f.txt line -- ok Read a text file starting at line. len f -- hex Put the length of a file in hexadecimal. put body f -- ok Create a file with the content of body. get f -- body Put the content of a file on the stack. cpy fsrc fdst -- ok Copy the content of fsrc into fdst. era f -- ok Erase file. ren fsrc fdst -- ok Rename file fsrc into fdst. pop a -- Pop symbol at the top of the stack. dup a -- a a Duplication symbol at the top of the stack. ovr a b -- a b a Copy second symbol to the top of the stack. swp a b -- b a Pull the second symbol to top. rot a b c -- b c a Pull the third symbol to top. add a b -- a+b Push the sum of two symbols. sub a b -- a-b Push the difference of two symbols. dec hex -- dec Convert hexadecimal number to decimal. hex dec -- hex Convert decimal number to hexadecimal. cat a b -- ab Concatenate two symbols. cmp a b -- bool Compare the names of two symbols. and a b -- bool Put true if both symbols are true. ora a b -- bool Put true if either symbol is true. rsz width height -- Resize the screen, puts true if resize is supported by Screen. out a -- Output symbol to Console/write. bye -- Quit. Source ../etc/m pc.tal.txt , Latest Repository https://git.sr.ht/~rabbits/m pc Support: Manifest manifest.html Theme theme.html Snarf snarf.html incoming: 2026 2026.html