DOS/9 — A Native Text Operating System

The premise

What if DOS had been allowed to evolve on its own terms — without Windows compatibility, without the GUI-first reorientation — and if along the way it had learned from Plan 9?

DOS/9 is not a recreation of MS-DOS and not a Linux distribution with a retro skin. It is an original kernel that inherits the spirit of DOS — single-user, text-first, the shell as the center of the universe — while applying Plan 9's core insight at the kernel level: everything is a file, actually.

The target is the small-web community: people who run Gemini capsules, use Gopher daily, and believe a computer should be a thing you can understand. If 200 of them try it and 20 use it weekly, the project has succeeded.

Shell is the OS

The command line is the primary interface, workflow, and control surface. Not a fallback from a GUI that doesn't exist.

Everything is a file

Devices at /dev, processes at /proc, network state at /net, disk at /disk. No separate APIs. Same tools everywhere.

Small web native

Gopher and Gemini clients are system tools, not third-party apps. The /net filesystem follows the Plan 9 model.

What's running

A real OS. Not a demo.

Phases 1 through 4b are complete. The kernel runs, schedules processes, enters user mode, and talks to the network — all written from scratch in C and assembly.

Kernel

GRUB / Multiboot
GDT, IDT, PIC remapping
PIT timer at 100 Hz
Physical memory bitmap
4KB paging, higher-half
Kernel heap (kmalloc/kfree)
Preemptive round-robin scheduler
Ring-3 user processes
ELF loader
int 0x80 syscall gate

Filesystem

VFS with multi-mount namespace
/dev — kbd, console, null
/proc — live process table; rm kills
/mod — loadable kernel modules
/disk — DOS9FS on ATA PIO
/net — Plan 9-style network FS
Anonymous pipes
dup, dup2
O_CREAT, SEEK_SET/CUR/END
Per-process fd tables

Networking

PCI device enumeration
RTL8139 NIC driver
Ethernet + ARP
IPv4 + ICMP
TCP + UDP
DHCP auto-config at boot
DNS resolver (UDP A-record)
/net/resolve — hostname→IP via VFS
/net/tcp/clone — connection model
Gopher client (hostname-aware)

Userland

Ring-3 shell — history, tab complete
Scripting: variables, if, for, loop
Pipeline syntax (left | right)
TUI toolkit — 16-color ANSI
Two-pane file manager (NC-style)
Full-screen text editor
Package system (.d9p + CRC32)
Minimal libc (stdio, malloc, string)
argv support, crt0
cat, hello userland programs

Roadmap

Built in the open.

Each phase ships when it works. No marketing timelines.

Phases 1–2: Kernel foundation

Boot · memory · scheduling · VFS · syscalls · ring-3

GDT/IDT/PIC, paging, heap, PIT timer, preemptive scheduler, ELF loader, int 0x80 syscall gate, VFS with devfs/procfs/diskfs, ring-3 user processes, minimal libc.

Complete

Phase 3: The userland

Shell · scripting · TUI · editor · packages

Ring-3 shell with history and tab completion, scripting (if/for/loop/variables), anonymous pipes, TUI toolkit, two-pane file manager, full-screen editor, .d9p package system.

Complete

Phases 4a–4b: Networking

TCP/IP · DHCP · DNS · Gopher

PCI enumeration, RTL8139 driver, full Ethernet/ARP/IP/TCP/UDP/ICMP stack, DHCP auto-config, DNS resolver, Plan 9-style /net VFS, Gopher client with hostname support.

Complete

Phase 4c: TLS + Gemini

BearSSL · Gemini browser

Port BearSSL (~50KB, designed for constrained systems) as the TLS layer, then build a native Gemini browser on top. Gemini is only reachable over TLS.

In progress

Phase 4c cont.: Readers

RSS · Finger · IRC

Native RSS reader, and possibly Finger, NNTP, and IRC clients — protocol-native tools, not ports of UNIX programs.

Planned

9P-style remote mounts

Aspirational

Mount a Gemini capsule as a local directory. Browse it with ls. Read it with cat. The moment DOS/9's thesis becomes undeniable — and the moment the Plan 9 influence stops being a metaphor.

Aspirational