Palm OS is not a console: it is the operating system of the Palm personal digital assistants (PDAs), introduced in 1996 with Palm Computing's Pilot 1000. Calendar, address book, notepad, calculator: these pocket machines with a monochrome touchscreen, driven with a stylus and powered by two AAA batteries, defined the category and sold by the tens of millions before being swept away by smartphones.
The distinctive part of the input method is Graffiti, a simplified alphabet: you do not draw letters the usual way but with a single-stroke shape, learned in a few minutes, that the machine recognises very reliably. A dedicated area at the bottom of the screen is reserved for that writing, next to shortcuts to the main applications.
Above all, Palm OS benefited from a huge and very accessible software library: the application format was simple, the development kit was free, and thousands of programs — including many free games, puzzles, ports of classics and shareware — circulated freely. That catalogue is what Recalbox brings back, by emulating a Palm m515, one of the last colour-screen models.
Emulator availability per board:
| Emulator | RPI3/RPI02W | RPI4/400 | RPI5/500 | OGA/OGS/RG351 | PC | RG353 |
|---|---|---|---|---|---|---|
| Libretro Mu | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
Palm OS is available on every board supported by Recalbox.
Mu is the only emulator for this system and therefore the default one. It reproduces a Palm m515 running Palm OS 4.1 and needs the machine's ROM to do so (see the BIOS section below). It supports neither netplay nor softpatching, but it declares support for CRT display. RetroAchievements are not available on this system.
A controller is required, but the Palm has neither a D-pad nor action buttons in the console sense: everything is done with the stylus on the touchscreen. The emulator reproduces that stylus with a pointer you move with the controller and "press down" with a button; the Palm's physical keys (the four application buttons and the up/down scroll) are mapped to the controller as well. The exact mapping can be reviewed and changed in the Controls menu of the RetroArch quick menu.
| File name | Description | MD5 | Emulators |
|---|---|---|---|
palmos41-en-m515.rom |
English Palm OS 4.1 ROM for the Palm m515 (mandatory) | 83cb1d1c76e568b916dc2e7c0bf669f6 | Mu |
bootloader-dbvz.rom |
DragonBall VZ processor bootloader (optional) | 9da101cd2317830649a31f8fa46debec | Mu |
Place the files like this:
/recalbox/share/bios/palm/
├── palmos41-en-m515.rom
└── bootloader-dbvz.rom
Without
palmos41-en-m515.rom, nothing will start: it is the machine's operating system, and the emulator has nothing to run without it. Check the MD5 of the file, as a correct name does not guarantee correct content: Recalbox's built-in BIOS checker (STARTthenBIOS CHECKING) lists missing or incorrect files.
Put your applications and games in:
/recalbox/share/roms/palm/
Supported extensions: .prc .pdb .pqa .img .zip
These extensions are not cartridge images but Palm file formats:
| Extension | Content |
|---|---|
.prc |
Palm Resource Code — an application or a game; this is the file you launch |
.pdb |
Palm Database — a data file accompanying an application (levels, dictionaries, books…) |
.pqa |
Palm Query Application — content-browsing application, rare and mostly unusable offline |
.img |
full memory image of a Palm, with its applications already installed |
A game shipped as several files (a
.prcalong with one or more.pdb) will only work properly if its data files are present in the folder too; the.prcis always the one you launch. Many Palm programs were free or distributed as shareware, but not all of them are free of rights: check the licence of the software you download.