rpix86

rpix86 emulates MS-DOS. It reads 1 file, 1 of them required: without a required file it does not start games.

About this profile

Detail	Value
Type	standalone
Classification	Other
Source	http://rpix86.patrickaalto.com/rdown.html
Upstream	none: the source is the project itself
Version	0.19
Profiled	2026-10-20
Profile	YAML, JSON
Cores	rpix86
Systems	MS-DOS
Checks the file by	existence

Technical notes

Patrick Aalto's x86 DOS emulator for the Raspberry Pi, freeware and closed source. Profiled from the binary RetroPie installs, files.retropie.org.uk/archives/rpix86.tar.gz (sha256 8591b715f7c5...ad328d), an ARM EABI5 executable whose banner reads "rpix86 (Raspberry Pi x86 emulator) v 0.19" with "BIOS date: Jun 28 2015". The BIOS, VGA and sound emulation are inside the binary. Its strings name no ROM, font or patch file, only the shell below, /boot/config.txt (overscan defaults), the input and serial devices, and the log and screenshot files it writes.

C:\ is the directory given with -d, the working directory by default (usage text). The emulator looks for its shell as C:\4DOS.COM or C:\4DOS\4DOS.COM. When neither exists it stops with "Unable to find 4DOS.COM command interpreter (shell)" and offers to fetch it with "wget http://rpix86.patrickaalto.com/4DOS.COM". RetroPie runs the binary from its install directory and unpacks files.retropie.org.uk/archives/4dos.zip (sha256 801441f3f65e...5b636a, 4DOS 7.50 from JP Software) there (scriptmodules/emulators/rpix86.sh).

Files

1 file: 1 required, 0 optional.

In this collection: 1 in repo and 0 missing.

Required

4DOS.COM required in repo

4DOS 7.50 command interpreter, the emulated DOS shell

• System: MS-DOS

• Size: 251.5 KB
• SHA1: a44f65d6318582501d22e27831eb2b1f0df58f79
• MD5: fc3a0078a13d98e611a62c1d6724f8c5
• CRC32: 8300d4cb
• Installed by the platform's own package on: retropie
• Source: rpix86 0.19 binary, strings C:\4DOS.COM and C:\4DOS\4DOS.COM
• Collection copy: bios/Other/rpix86/4DOS.COM

• Same bytes at rpix86.patrickaalto.com/4DOS.COM, the URL the binary downloads from, and in RetroPie's 4dos.zip. Read from the emulated C: root, not a BIOS directory. The author's rpix86.zip and rpix86.tar.gz hold the binary alone, and RetroPie unpacks 4dos.zip into the install directory.

Next steps

• Get your files, for the setup you play on
• Every system, and the files each one needs
• When a game does not start

Data as of 24 October 2026.