3182da3965
Claude Code keeps per-project memory at <home>/.claude/projects/<key>/,
where <key> is the project's absolute path with every separator and the
drive colon turned into a dash. That makes it both rename-fragile and
machine-specific, and this project has hit each of those once:
- D:\DEV\Schunix -> D:\DEV\SchOS changed the key, and 43 memories were
invisible until moved across by hand.
- Development happens from Windows and from Linux, and each looks in a
different place for the same checkout.
Committing .claude/memory/ fixes both -- git carries it across renames
and between hosts -- and `import` puts it wherever the local machine
expects. .claude/settings.local.json stays ignored: those are per-machine
permissions.
The colon maps to a dash rather than being dropped. Deleting it gives
D-DEV-SchOS, which matches nothing and silently finds zero memories; that
was the first attempt. On Git Bash the key comes from `cygpath -w`,
because Claude Code is a Windows program and sees D:\DEV\SchOS, not
/d/DEV/SchOS.
4.7 KiB
| name | description | metadata | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| schunix-device-model | The bus-agnostic device model behind /proc/devices, and the settled decision on how Linux drivers may be used. |
|
Built 2026-08-08. include/device.h + kernel/dev/device.c, readable at
/proc/devices. Written up in docs/drivers.md. Supersedes the two separate
arrays in kernel/drivers/registry.c as the answer to "what is attached".
Bus is provenance, class is capability — keep them separate. bus is
platform/pci/usb; class is display/input/storage/net/bus. A USB
disk and a SATA disk are both storage. device_find_class() is how a consumer
asks for "the display" without naming a driver, which is what stops the next
display driver requiring edits to every consumer.
Where a driver claims a device, the driver's opinion beats the descriptor's:
struct usb_driver gained a devclass field distinct from the USB interface
class, because the descriptor says what the device claims to be and the driver
knows what it made of it. A USB driver that forgets to set it lands in other.
Registration is automatic in pci_bind() and usb_bind_all() so a driver
cannot forget; platform devices are registered by hand in
platform_register_devices() in registry.c, in one readable block, matching
that file's existing "a list you can read beats a list assembled by side
effects" reasoning.
Flat list with a bus tag, not a device tree — nothing walks a hierarchy yet. No lock: everything is added during single-threaded boot. USB hotplug would break both assumptions and needs a spinlock plus a reader lock in procfs.
The display class
include/display.h + ops in kernel/dev/vga.c, published on the device by
vga_pci_driver.ops. struct pci_driver gained an ops field for this —
it has to live on the driver, not be set inside probe(), because
pci_bind() registers the device after probe returns.
Ops: mode, acquire, present(x,y,w,h), wait_vblank. The wrappers in
device.c null-check every op so consumers are not each written around a
maybe-absent vtable.
- Back buffer comes from
dma_alloc(), which is the wrong pool and is used because it is the only physically contiguous allocator in the kernel — kalloc hands out single pages. 1.9 MB of a 4 MB arena meant for device rings. Allocated lazily on firstacquire(), never at boot. The real fix travels with the E820 work (schunix-smp-and-memory-bugs). - vblank is the 1987 VGA port 0x3DA bit 3, not VBE — VBE's protected-mode interface for this is optional and usually absent. Two loops (wait for the current retrace to end, then for the next to begin), or you return immediately having just missed one. Both loops are bounded so hardware that never reports retrace cannot hang a caller holding the console lock.
echo d > /proc/sysrq runs display_selftest(); tools/dispshot.ps1
photographs it to build/dispshot.ppm — it was derived from crashshot.ps1 and
originally kept its output path, so the two silently overwrote each other and
crashqr.py then failed on a capture that was not a crash screen. The pattern is designed to fail visibly: quadrants slant on a
stride error, change colour on a bpp error, and the 1px inset frame clips on an
off-by-one in the present rectangle. Verified 2026-08-08.
The console still writes directly to the framebuffer; the two paths coexist deliberately. Routing text through the back buffer would mean presenting per character.
Linux drivers — settled 2026-08-08
Nexoniarz's decision, and the reasoning is correct: not shipped, ever; the user installs one themselves through a device manager and Schunix loads it.
- Distribution is what triggers the GPL. A user obtaining and loading a driver on their own machine is their act, not ours.
- Implementing a loader from published documentation is clean-room and fine — it stays clean-room only if written from docs, not transcribed from Linux source. See schunix-licensing.
Also worth keeping separate when this resumes: "loadable modules" (a stable ABI plus a linker/loader, on top of this model) and "drivers out of kernel" (user-space processes, DriverKit-style — needs IPC and mmap, both of which already exist). They get bundled together in conversation and are different projects.
Adding /proc files
Three places, all needed: a PROC_* id and a case in proc_gen_global() in
kernel/dev/procfs.c, and a row in the globals[] table in
kernel/fs/procfs.c. Miss the third and the file exists but cannot be opened by
name. sb_pad() exists there now for column layout — cprintf has no width
specifier.