EDOSx86_64

An operating system in Rust.

EDOS boots on UEFI, brings up every core on the machine, and drops you into a compositing desktop: a browser, an editor, a file manager and a package manager, over its own scheduler, filesystem, network stack, USB stack and window system.

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/dev/ttyS0

[0.000000] <cpu-0:kernel> Booting...
[0.000000] <cpu-0:kernel> cmdline: "root=UUID=87654321-4321-8765-cba9-987654321fed rootfstype=efs"
[0.000000] <cpu-0:kernel> Initializing frame allocator
[0.000000] <cpu-0:kernel> Mapped kernel heap at 0xffffc00000000000-0xffffc00000100000
[0.000000] <cpu-0:kernel> Initializing acpi tables
[0.000000] <cpu-0:kernel> Initializing apic
[0.000000] <cpu-0:kernel> Initializing hpet
[0.000000] <cpu-0:kernel> APIC frequency: 999971485 Hz (999) MHz
[0.000000] <cpu-0:kernel> TSC frequency: 3493742000 Hz (3.49) GHz
[0.003893] <cpu-2:kernel> SYSCALL/SYSRET enabled
[0.015329] <cpu-2:kernel> Initializing scheduler
[0.022432] <cpu-2:kernel> [smp] AP online: LAPIC id 2
[0.023745] <cpu-1:kernel> [smp] AP online: LAPIC id 1
[0.027687] <cpu-3:kernel> [smp] AP online: LAPIC id 3
[0.110638] <cpu-0:kernel> Reaper thread started (tid=1)
[0.112039] <cpu-0:kernel> Evict kthread started (tid=2)
[0.216985] <cpu-0:kernel> Scanning PCI devices...
[0.219784] <cpu-0:kernel> Found 8 PCI devices
[0.243031] <cpu-2:kernel> xhci: version 0.0, 64 slots, 8 ports
[0.244978] <cpu-0:kernel> virtio-gpu: initialised, control=64, cursor=16, blob=false, irq=true
[0.250968] <cpu-0:kernel> virtio-gpu: 1280x800 @ 74Hz
[0.253084] <cpu-1:e1000e:k:6> e1000e: initialized, MAC 52:54:00:12:34:56
[0.253110] <cpu-1:e1000e:k:6> net: dhcp: sending DISCOVER
[0.253360] <cpu-1:e1000e:k:6> net: dhcp: received ACK, IP 10.0.2.15
[0.285375] <cpu-1:hda:k:7> hda: /dev/dsp registered
[0.285422] <cpu-1:ahci:k:4> AHCI CAP: SNCQ=true, NCS=31 (32 command slots)
[0.285834] <cpu-1:ahci:k:4> Found SATA drive on port 1
[0.287168] <cpu-2:kernel> xhci: initial enumeration complete
[0.343483] <cpu-0:kernel> verify_kernel_no_phys_aliasing: 2737 kernel-half mappings, no aliases
[0.353264] <cpu-1:window-input:k:14> Window input routing thread started
[0.760503] <cpu-0:system-mount:k:15> Root partition: UUID=87654321-4321-8765-cba9-987654321fed on device 0
[0.761005] <cpu-0:fs:k:13> efs journal: replay scan start tail_seq=1 tail_block=0
[0.761138] <cpu-0:fs:k:13> efs journal: scanned, nothing to replay
[0.761163] <cpu-0:system-mount:k:15> Root filesystem mounted
[0.764001] <cpu-1:system-mount:k:15> Spawned bin/edos-init tid=18 cpu=3
[Terminal] Spawned /bin/sh (PID: 29)

Verbatim serial output from a four-core boot, replayed at its own timestamps. The long pause is the PCI scan; the second one is mounting the root filesystem.

The applications menu

A browser, an editor, a file manager, a package manager.

Four graphical programs. Each is an ordinary std Rust binary with a main(), and each draws through the same toolkit. None of them lives in the compositor: kill one and the desktop stays up.

The EDOS browser filling the screen, showing this site’s syscalls page: a heading, a two-column table of registers, and a syntax-coloured Rust listing of the syscall2 wrapper.

Browser `edos-web`

Type a URL, get the page. Links, history, images, tables and CSS, over HTTPS to the real internet; the page here is this site, fetched by the guest that drew it.

The EDOS graphical editor showing a Rust file: a file tree on the left, a tab strip, syntax-coloured code with line numbers, and two edited lines marked in the accent colour down the gutter.

Editor `edos-edit`

Open a file, change it, save it. A tree of the folder down one side, a tab per open file, and the code coloured by language.

The EDOS file manager showing /share/wallpapers, with a thumbnail of the selected image, its size in bytes, its modification time and the volume it lives on in the details pane.

File manager `edos-files`

Move around the disk without typing a path. Every mounted volume down one side, and a pane that previews the selected image and says how big it is and where it lives.

The edos-grab window: a search field and an Update button above a list showing edos-edit with its icon, version and summary, and a detail pane on the right giving the version, category, size, the paths the package installs, and Install and Remove buttons.

Packages `edos-grab`

Search for a program and install it. Removing one takes back exactly the files it wrote, and nothing installs unless its checksum matches the signed index it came from.

The shell is a scripting language: functions, arithmetic, globbing, heredocs and job control, with every block closed by end rather than fi and done.The language reference.

ps, on an idle desktop

The kernel's own thread table is the feature list.

Nothing below is a wrapper around someone else's driver. Each of these threads is spawned by name at boot, and each one is a subsystem written for this kernel.

PID	Name	What it does
1	reaper	Tears down dead threads and releases their file descriptors and mappings.
2	evict-inode	Does the blocking half of inode eviction, so no drop path ever waits on disk.
3	klogger	Drains the kernel log ring into /dev/klog, which is what dmesg reads.
4	ahci	Submits and completes NCQ commands, up to 32 tags in flight at once.
5	xhci	Runs USB transfers: HID keyboard and mouse, and mass storage.
6	e1000e	Moves Ethernet frames and drives DHCP and DNS.
7	hda	Intel HDA playback, exposed as /dev/dsp.
8	vga	virtio-gpu scanout and the hardware cursor.
9	tcp-retransmit	TCP timers: retransmission, delayed ACK, and TIME-WAIT expiry.
10	keyboard	Decodes scancodes into key events.
11	mouse	Reads HID boot-protocol reports and moves the pointer.
12	block_writeback	Flushes dirty pages, gated on the journal having committed.
13	journal_committer	Commits EFS metadata transactions.
14	fs	VFS work that cannot run inline: mounts, evictions, async page fill.
15	window-input	Routes keyboard and pointer events to the focused window.
17	ahci_watchdog	Catches NCQ commands that never complete.

A filesystem, not a port

EFS is an extent-based filesystem with a metadata journal, written for this kernel and formatted by efs-mkfs, which runs on the host and inside EDOS. Mounting replays the journal when the last shutdown was unclean. Above it sit a page cache, a block cache, write-back gated on journal commits, and read-ahead; below it, AHCI with native command queuing.

How EFS works

A terminal showing df, mount and stat output in EDOS.

A network stack that talks to the internet

Ethernet, ARP, IPv4 with fragment reassembly, ICMP, UDP and a TCP state machine, plus DHCP and DNS clients. The guest takes its address from DHCP within a millisecond of the NIC coming up. The same driver runs on real Intel I219 and I218 hardware.

Inside the network stack

A terminal in EDOS running ping, dns and wget against the internet.

The desktop is userspace

The kernel owns a window registry and routes input to whichever window has focus. Everything you can see is an ordinary process: edos-wm composites and draws decorations, edos-taskbar and edos-terminal are separate programs, and they share pixel buffers with the compositor through shared memory.

How the window system fits together

The EDOS widget toolkit demo window with buttons, a text input, checkboxes and sliders.

50 seconds, no cuts

Driven from outside the guest

A shell, the file manager over /bin, the package manager fetching the editor off this site, and the browser reading the page that lists it. Recorded straight off the framebuffer over QEMU's monitor socket: keystrokes and pointer events go in, frames come out. It is how the OS gets tested.

The tree

What is actually in here

Rust: 115,794 lines across 479 files
Kernel: 53,634 lines, no_std, one binary
Userspace: 132 programs on a forked Rust std
Syscalls: 124, through SYSCALL/SYSRET
Targets: x86_64-unknown-none, x86_64-unknown-edos
History: 1,660 commits

Get it running

Build it, then boot it

git clone https://github.com/edg-l/edos-v2
cd edos-v2
make all      # userspace, kernel, bootable ISO
make run      # QEMU: q35, UEFI, KVM, 4 cores

The kernel builds on plain nightly. Userspace links a real std, so it needs a custom toolchain built from a Rust fork; the build guide walks through it. Prefer a prebuilt image? Downloads.