For five weeks I’ve been chasing more battery life for my laptop. I’ve been churning out several projects every week to replace my old desktop setup.
Two suites make up the endeavour: CHasm and Fe₂O₃.
They are now grouped into one project: Watt — The Lean Desktop Project.
Why?
Pick the metric. The reason the fan went quiet, the battery now lasts 19 hours, and the desktop now fits me perfectly… it’s all the same metric: watts. Every loop, poll, fork-on-a-timer is a watt the battery doesn’t give back. Get the watts down and everything else follows: Near instant startups, snappy response, unintrusive, tailored = me happy.
What’s in there
A new page lives at https://isene.org/watt/ with one paragraph of intro and two doors:
- CHasm the bedrock: Shell, terminal, tiling window manager, status bar, file viewer, font rasterizer, screen locker. The whole X session in under 500 KB of executable code. No libc, no toolkit, no dynamic linking, no runtime.
- Fe₂O₃ the application layer: Editor, file manager, web browser, messaging hub, calendar, astronomy, movies, music, color picker, battery drain-o-meter. Single static Rust binaries on one shared TUI foundation.
Both projects center on three goals, in priority order:
- More battery life. Polling, waking, and forking on a timer are suspect. Prefer filesystem watches,
select, blocking reads. - Lightning fast. Near instant startup, instantaneous user feedback. No interpreters in the hot path.
- No wasted CPU cycles. Gate every feature so its code path is fully cold when not in use.
The current numbers
- 3.6 W idle, screen at 70 % brightness
- ~19 hours of idle battery life on the 70 Wh cell
- < 500 KB of executable code for the entire CHasm session
- ~9 µs shell startup (CHasm
bare) - Fourteen Fe₂O₃ binaries + five shared libraries, the asm suite, plus four Rust TUI configurators for the asm rc files, the newest member being a TUI Spotify client.
One page
These two suites kept getting linked together in conversations, in the lobste.rs threads, in the agency-stack post, and in my own head. Splitting them across two top-nav links on this blog was off. A single door is better. The detailed per-suite pages are reached through it.
Five weeks of chasing a desktop that asks for as few watts as possible. Still chasing.
Link to this post: https://isene.org/2026/05/Watt.html