| Filename | Latest commit message | Latest commit date |
|---|---|---|
3a0b570c23
Two reports from an Asus TUF FA607NU, which now gets as far as the splash: the progress bar does not move, and after a resolution change the screen keeps the background colour with no mark and no bar. Both point at the same code, and it is code this loader did not have a week ago. **Modes were being matched on every frame.** mirrors_match() ran from inside mirrors_show(), so every menu redraw and every segment of the kernel load asked another display adapter to change mode. On QEMU that is instant and idempotent. On real hardware a mode set can take the best part of a second, can blank a panel while it happens, and -- on a laptop -- is quite often being asked of the *same* panel reached through a second GOP. A loader that does that in the middle of drawing a progress bar is a loader that shows a background colour and then waits on a firmware call that is not coming back. It now happens exactly once, at discovery, before anything is drawn. The second head is centred and cropped afterwards rather than re-moded, and the booted system matches resolutions anyway because the kernel driver and vgpud both follow the console. **And mirroring no longer runs per segment of the kernel load.** Copying a megabyte-and-a-half framebuffer to every other adapter, three times, to animate a bar on a screen nobody is looking at. **One refusal now turns it off for the rest of the boot**, and `\schos\nomirror` -- an empty file whose only job is to exist -- turns it off before it starts. There is no console to ask a question on at that point and no menu to reach if the menu is what is broken, so the answer has to already be on the volume. That also makes it a one-file experiment on hardware we cannot instrument. **The loader names its stages on screen.** After the splash, print() goes to the serial port and nowhere else, so on a machine with no serial port a stall leaves a progress bar and no information at all. Every stage after the kernel load now labels itself under the bar -- Reading the console font, Reading the memory map, Leaving the firmware -- so the last thing on the screen names the call that did not return. Past ExitBootServices there is nothing left to report with, which is itself worth knowing: a machine stopped on the last label stopped in the jump. Opening the boot volume moved ahead of the display, because what is on the volume now decides some of what the display does. Both supported configurations: one boot each, no traps, no panics, socktest and memfdtest green. Mirroring still verified end to end -- F8, a resolution change, boot, and both heads byte-identical at the new mode. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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| .. | ||
| architecture | ||
| branding | ||
| guides | ||
| history | ||
| niveus | ||
| plan | ||
| Website | ||
| licensing.md | ||
| README.md | ||
SchOS documentation
Four kinds of document, kept in four directories, because they answer four different questions and go stale at four different rates.
| architecture/ | What SchOS is | Present tense. Describes what is built and working. |
| plan/ | What SchOS will be | Future tense. Everything here is unbuilt. |
| guides/ | How to work on it | Imperative. Build it, test it, add to it. |
| history/ | Why it is the way it is | Past tense. Bugs whose cause is not visible from the fix. |
Plus two that belong to no category and apply to everything: licensing.md — read it before copying anyone else's code in — and branding/, which holds the marks and the rules for using them.
The rule that keeps this from rotting
When something is finished, it moves from
plan/toarchitecture/and is rewritten as a description of the thing rather than a record of building it.
A completed item is not a ticked checkbox. A ticked checkbox says the work happened; it does not say what the work produced, and six months later the checkbox is the only thing left and it explains nothing.
So finishing a piece of work has three steps, and the third is not optional:
- The code works and is tested.
- The plan entry is deleted.
- A description exists in
architecture/written for somebody who was not there — what it does, what shape it has, what it costs, and what it still does not do.
This is not bookkeeping. The tree has already proved it necessary: the network stack was finished, verified end to end, and for a month afterwards the only description of it anywhere was a checkbox in a roadmap, four levels of indentation deep, written in the past tense of somebody arguing for the work rather than explaining the result.
The "what it does not do" section is the one that pays. Every description in
architecture/ ends with one. A document that only lists a subsystem's
strengths is marketing, and the reader who most needs the document is the one
about to trip over a limitation nobody wrote down.
Start here
New to the tree → architecture/README.md, the system layer by layer, then guides/layout.md for where the files are.
Trying to build it → guides/building.md.
Wondering what happens next → plan/1.0.md, which is the finish line and the register of everything half-built. Then plan/README.md for the order.
About to start something new → the register, first. Nothing new starts while it has rows in it, and a row leaves only by being finished or deleted.
Something is broken and it feels familiar → history/. There is a good chance it is in there.
architecture/ — what SchOS is
| README | The system, layer by layer. Read first. |
| boot.md | Firmware to the first userspace process. |
| kernel.md | SchIFT: memory, processes, scheduling, traps, signals, SMP. |
| syscalls.md | The call table, and the Linux personality that lets real software run. |
| filesystem.md | The VFS, the buffer cache, procfs, mounts. |
| schfs.md | SchFS: the copy-on-write root filesystem. |
| devices.md | The device model, driver binding, the class vtables. |
| usb.md | xHCI, the USB core, and the class drivers. |
| graphics.md | Framebuffer, text rendering, console, and the crash screen. |
| terminals.md | The six virtual terminals, and how one is switched to. |
| networking.md | Drivers, lwIP, sockets — Unix and INET. |
| init.md | schinit, PID 1 as a role, and the job manifests. |
plan/ — what SchOS will be
| README | The three current decisions and the order they happen in. |
| 1.0.md | The finish line, and the freeze. What 1.0 contains, what is deferred, and the register of every half-built thing in the tree. |
| foundations.md | The kernel work everything else is blocked on. |
| wayland.md | The GUI stack, and what gets deleted to make room. |
| hybrid.md | Moving drivers out of the kernel. |
| schapi.md | The long-term API layering, and the compatibility promise. |
| roadmap.md | Everything else still open. |
guides/ — how to work on it
| building.md | Prerequisites and the build, per host. |
| testing.md | The harnesses, and what each one actually proves. |
| layout.md | Repository map, and how to add a program or a port. |
| adding-a-driver.md | Writing one, binding it, publishing its class vtable. |
branding/ — the marks
| README | Shift, the one mark: what it is for, the colour rule, why an icon and a mascot were removed, and why a raster is committed next to its SVG. |
history/ — why it is the way it is
| README | What belongs in here and what does not. |
| kernel.md | Bugs whose cause was nowhere near their symptom. |
| schfs.md | The filesystem's own, from the same period as its design. |
| moving-to-linux.md | The Windows-to-Fedora move, kept for the parts that recur. |
Writing one of these
Four conventions, all of them observable in the existing files:
State the cost. Every design choice gave something up. A document that does not say what is a document that will be argued with later by somebody who only sees the downside.
Prefer the measured number to the remembered one. "500 of 3565 files carry the advertising clause" is worth more than "some do", and it was worth the minute it took to count.
Write down the bug that shaped it. Half the non-obvious code in this tree is non-obvious because something failed once. If a design is strange, the strangeness is load-bearing and the reader deserves to know why before changing it.
No dates in headings. A date in a heading turns a description into a
changelog, and the description is the thing with a long life. Dates belong in
history/, where they mean something.