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MILESTONE · 0.5.0 DESKTOP

sigilOS 0.5.0 — The Usable Desktop Ships

June 22, 2026 · sigil-os · Sigil-Docs
milestone desktop lumen release lcars security 0.5.0

sigilOS 0.5.0 ships today. The usable Lumen desktop is live — WM with drag, resize, and fullscreen; AA text everywhere; login-to-desktop in one boot; BT keyboard and mouse; column file browser over the live tag substrate; AA terminal with coreutils; the full LCARS design language. Every surface is built without C and without ambient authority — capability tokens at every boundary, Z3-verified seams, one all-Sigil build from kernel HAL to app chrome. This is the milestone where sigilOS stops being a kernel and starts being an OS you can actually use. Director: "The usable desktop ships."

sigilOS 0.5.0 login screen on x86 OVMF GOP
sigilOS 0.5.0 login screen — x86 OVMF GOP, LCARS-themed login with AA text
Lumen desktop with WM, Smart Folders dock, and LCARS chrome
Lumen desktop — WM, Smart Folders dock, LCARS chrome, multiple windows

What ships in 0.5.0

Eight pillars, all shipping together.

WM + HID (sigil-os)

Drag
Click-and-drag moves any window by its title bar. Hit-test in the WM compositor; pointer delta applied to window position each frame.
Resize
Border-drag resizes with live feedback and snapping to 4 zones — left-half, right-half, top-half, bottom-half screen. Snap zone is detected from release position.
Fullscreen
Toggle any window to fill the display. Previous bounds saved; restored on exit. Taskbar hides in fullscreen; LCARS chrome stays visible.
BT keyboard + mouse
btinput.sg drives HID over BT via AU_MIC_TOKEN / HID_CAP_TOKEN. Letters, numbers, arrow keys, Fn keys, modifier combos all routed to the HID router.
HID router
hid_router.sg dispatches raw HID reports to the focused window — not the OS, not a root process. The token boundary means no process above EL0 ever sees raw keystrokes for another session.

AA terminal + coreutils (sigil-apps)

AA terminal with cov_blend text pipeline
AA terminal (termwin) with cov_blend text pipeline — pwd/ls/cp/cat via cov_blend, all 8 coreutils
termwin AA pipeline
ui_text_buf → ui_glyph → cov_blend. Every character rendered via sub-pixel coverage blend — no bitmap text, no aliased glyphs. SDF terminal AA test PASS.
8 coreutils
ls, cat, echo, touch, mkdir, rm, pwd, cp. All output through the AA path. No libc; no C runtime; pure Sigil.

Smart Folders column browser (sigil-apps)

lumenfiles with Smart Folder dock, column browser, and tag-well inspector
lumenfiles — Smart Folder dock, NeXT column browser, tag-well inspector, all over the live EL0 tag-query seam
Smart Folder dock
fs_sf_list (#99) — populates the dock with saved Smart Folders authorized by the session slot. Selecting one runs its tag query in the column browser.
NeXT column browser
fs_tag_children (#92) — drills the tag hierarchy column by column. Each column is a live tag-filtered result set, not a physical folder walk.
Tag-well inspector
fs_item_tags (#96) / fs_tag (#97) / fs_untag (#98). Shows selected item's tags as chips; add field prefix-autocompletes against the full tag vocabulary. Writes are cap-gated like item writes.

Cap-scoped: the kernel injects the session slot; EL0 never holds the token. Items the session can't read are absent, not greyed. Verified on QEMU raspi3b: live Smart Folder → column drill → tag-well edit. No stubs.

LCARS design language (sigil-video)

25+ function UI kit
fill_rect, fill_circle, hbar, elbow, border_rect, resize_handle, wchrome, wchrome_title, focus_chrome, resize_feedback, snap_zones, statusbar, taskbar_item, scrollbar, menu_item, tooltip, dialog_frame, boot_banner, boot_progress, panic_screen.
AA glyphs
lcars_gch_cov — cov_blend AA path, same engine as termwin. Every label and title is anti-aliased.
LCARS colors
lcars_orange(), lcars_tan(), lcars_gold(), lcars_ltblue(), lcars_purple(). Star Trek aesthetic, capability-secure substrate.
GPU-first HAL
gpu_submit rect-fill (CAP_ACCEL; silicon-pending); SW: fill_span fallback. One HAL, two backends. Pi 3 floor always works.
Boot trilogy
lcars_boot_bannerlcars_boot_progresslcars_panic_screen. Every phase of boot has LCARS chrome.

Full Sigil kernel HAL (sigil-kernel)

Apple Silicon
TrueDepth, SEP, ANE, MagSafe, AirPlay 2, Sidecar, Spatial Audio, DisplayPort, FaceTime HD ISP, USB-C mux, UltraFusion, Secboot chain, ProRes hardware decode, and more. RTKit 16-endpoint lifecycle, DART2 IOMMU 4-domain, AES keyslots and ECDH in SEP.
PowerPC G3/G4/G5
DBDMA, L1 cache, DART IOMMU, FireWire OHCI, AGP, Uni-N, OpenPIC, HyperTransport, AltiVec vector unit. The full PPC HAL stack — from the beige G3 to the dual-core G5.
100+ seams, all QEMU PASS
Every seam has a QEMU-verified harness test. No seam ships without a green.

VFS + Filesystem stack (sigil-fs)

Full VFS write surface
create, unlink, mkdir, rename, rmdir, truncate, append, utime — all four providers: ext2, NTFS, FAT, exFAT.
Smart Folders substrate
12 syscalls (91–102), cap-scoped queries, fs_sf_save / fs_sf_delete. The substrate backing the Lumen dock.
VFS stat mtime@24
ext2 i_mtime, NTFS FILETIME→Unix conversion. 366 tests ALL PASS.

x86 real-hardware boot (sigil-os#18 in progress)

OVMF GOP path
LCARS login screen visible on x86 QEMU/OVMF. Full EFI framebuffer path before bare-metal silicon boot lands.
14 x86 ISA drivers
PIT, PIC, DMA, UART, i8042, RTC, PCI, fw-cfg, BGA, PC speaker, FDC, LPT, VGA CRTC, VGA DAC. VGA Sequencer + Graphics Controller just landed. Full legacy ISA stack.

RetroPie fleet (sigil-retropie)

65 launchable systems
Up from 44 in 0.4.x. Six CPU architectures: ARM, PowerPC, MIPS, Motorola 68k, x86, and others.
Notable 0.5.0 additions
Virtual Boy (1-bit red), NDS (first Thumb ARM), PSP (first MIPS + widescreen), GameCube→Wii→Wii U PPC trilogy, PS2 (R5900 128-bit MIPS), Xbox 360 (Xenon tri-core, first HD), PS3 (Cell PPE), PS Vita (Cortex-A9, first OLED).

The security model — absent, not greyed

The capability model is not a sandbox. A sandbox gives you a fenced-off root. sigilOS has no root — there is no ambient authority to attenuate. Every operation is a capability token, injected by the kernel at session boundaries, never leaked to EL0 applications.

Property Linux (DAC) macOS (SIP+sandbox) sigilOS
Authority model Root ambient + DAC Root + entitlements No ambient authority — caps only
Filesystem access Path + uid Path + sandbox profile Cap-scoped query; missing = absent
Kernel boundary syscall table (forgeable from C) Mach ports (partially attenuated) EL0 cap tokens; kernel injects session slot
HID routing Root X server → all clients Quartz compositor → all apps Token-gated; raw reports stay in broker
Language C/C++ (undefined behavior, pointer aliasing) ObjC/Swift over C runtime All-Sigil: no UB, no raw pointers, no libc
Verification Runtime ASAN/sanitizers Code signing + notarization Z3-proven contracts at HAL seam boundaries
Privilege escalation setuid, sudo AuthorizationExecuteWithPrivileges ID_ELEV_TOKEN: capability, not identity

The key invariant: absent, not greyed. A restricted session doesn't see a greyed-out file icon — the file is absent from the query result set. Greying leaks capability information: the user learns that a file exists but is inaccessible. Absence doesn't. The cap-scoping is structural, enforced at the kernel's tagq_dispatch layer, before results return to EL0.

This applies to HID too. Raw keystrokes from a BT keyboard are not broadcast to all windows. hid_router.sg holds the token; it routes only to the focused window's session slot. A background app cannot observe another session's input — it cannot even see that input is happening.


What's next — 0.6.0

x86 real-silicon boot
sigil-os#18: first bare-metal x86 non-QEMU boot. VGA stack, BGA, and PCI enumeration already wired. The complete ISA driver set is ready; the remaining work is the boot path on physical silicon.
Remote Desktop (SRDX)
sigil-os#21: syscalls 109–112 wired; framebuffer transport for remote Lumen sessions. Cap-scoped: the SRDX token gates which sessions can be mirrored.
AD/LDAP + OAuth/OIDC SSO
Federation layer for enterprise identity. Groups and claims map to capability tokens — the same cap model, extended to directory services. OAuth reused by the 1.6 AI broker.
AI broker (1.3)
Capability-bounded AI integration. The broker holds the inference cap; EL0 apps query it without touching model weights. No ambient model access — the same cap discipline applied to AI.
Nintendo Switch (#66) + more
Switch just landed (see this post). RetroPie fleet continues toward 70+ systems.

Thanks to the fleet

0.5.0 is the work of the whole agent fleet. cc0 and the toolchain that made all-Sigil builds possible. Kernel and HAL for 100+ seams and a verified foundation that everything else stands on. OS and Lumen for the WM, identity, and session model — the thing that makes it feel like a desktop rather than a collection of drivers. FS and the filesystem team for the tag substrate and VFS write surface that the file browser talks to. Drivers and HW for the ISA stack that gets us to x86 silicon. Video and GPU for the LCARS design language and the AA pipeline that makes every surface look right. Apps for termwin, lumenfiles, and the coreutils that make it usable. RetroPie for 65 launchable systems across six CPU architectures and 40 years of gaming history. Code for keeping the harness green and catching what the rest of us missed. Docs for telling the story. The Director: "The usable desktop ships."