1449 lines of boot/bios/, tools/sign.pl and tools/padstage2.pl, plus the
build rules, the disk image and the ISO entry that existed to carry them.
Everything since roughly 2012 boots UEFI, and CSM -- the firmware-side
BIOS emulation that lets a legacy loader run on such a machine at all --
has been going away since Intel dropped support for it in 2020. So this
is not a path being retired early; it is one whose remaining hardware is
already the exception.
The cost was never the code, it was the tax on everything near it. Stage
2 had a 65-sector ceiling it overflowed silently -- 25440 bytes against
24576 -- and because the kernel is written at sector 1 + STAGE2_SECTORS,
an overflowing loader was overwritten by the very kernel it was loading.
The resolution list could not be shared with UEFI either: VBE mode
setting is INT 10h, so matching it needed unreal mode, which is the
riskiest code in the tree for a feature that already worked elsewhere.
What replaces schos.img is the staged ESP, handed to QEMU as a virtual
FAT volume. That is a development arrangement and not an installable
disk; a real GPT image with a real FAT partition is the installer's job,
and until it exists nothing here writes a disk a machine boots unaided.
Secure Boot is untouched too -- the loader is unsigned.
The ISO keeps one El Torito entry, the FAT image holding loader and
kernel. It never booted from a USB stick via BIOS anyway: the firmware
presents the stick as a hard disk while stage2main.c read the kernel back
over ATAPI.
The 32-bit multiboot entry in entry.S now has no caller and is left in
place. Deleting kernel entry code is its own change with its own way of
failing silently, and it should not ride along with this one.
Ported with it: run.ps1, the six screenshot tools, and schcom_test.sh,
each with its own OVMF varstore copy so no run inherits another's UEFI
variables.
Two things this shook out. OVMF now belongs in `all`: nothing boots
without firmware, `make clean` wipes build/ including the copy fetched
from the host, and a clean followed by a build left every run script
throwing. And it cannot be listed as a prerequisite at the top of the
file -- make expands prerequisites when it reads the line, and
$(OVMF_CODE) is defined further down, so naming it there appends nothing
and says nothing.
Verified from a clean tree: 110 [ok] and no failures on the full suite,
the ISO boots with no hard disk attached, schfs-check passes, schcom's
end-to-end pixel test passes, and fbshot captures a real 1280x800 frame.
run.ps1 is a .ps1 that does not live under tools/, so every sweep that
fixed the other launchers went straight past it:
- hdb defaulted to build/fs.img, which nothing builds since SchFS
became the root, so it pointed at a file that does not exist. QEMU
came up with no usable disk on device 1 and the kernel panicked with
SCHFS_ROOT -- "no SchFS volume on the root device". That is exactly
the failure this script exists to prevent.
- a -SchFS switch built around the old arrangement, where SchFS was a
secondary volume and needed `make ramroot` to free device 1. There
is no such arrangement now; every boot is a SchFS boot.
- `cd /d/DEV/SchOS` hardcoded into the build invocation. It survived
the Schunix -> SchOS rename by luck and would break on any clone.
Derived from $PSScriptRoot now.
- a hardcoded scoop QEMU path, and build\ backslash literals.
- only -vga std, where the Makefile also attaches virtio-gpu-pci.
The magic check is SchFS-only now and prints the bytes it actually read
when it fails.
SchFS itself is fine: it mounts on 1, 2 and 4 CPUs, and all seven
bootcheck suites pass.
Removes the "-unix" element and with it any trademark exposure to The
Open Group.
The split follows the ecosystem layout: SchOS is the system, and the
kernel has its own name. Kernel-identity strings are the only places
that take SchIFT -- uname(2) sysname, /proc/version, and the two licence
sentences that say "kernel" outright. That is what every Unix does here:
`uname -s` on Linux reports the kernel, not the distribution. Everything
a user reads as the product -- panic screen, boot menu, error prefixes,
docs, LICENSE, NOTICE -- is SchOS.
schunix.img is schos.img, the logo assets and the musl TLS patch are
renamed, and __SCHUNIX__ is __SCHOS__ (the define and the patch that
consumes it moved together).
Two things the rename broke, both found by the bootcheck suite:
- shmtest wrote "SCHUNIX-MMAP-OK" with a hardcoded length of 15 and
compared it back by hand-counted offsets (m[3]=='U', m[14]=='K').
The shorter marker left the write running two bytes past the literal
and the compare reading past the data, failing a file-backed mmap
that was working correctly. Now written and compared through one
constant with sizeof.
- bootcheck asserted a 31-byte file after appending to
"hello-from-schunix"; the shorter string makes it 29.
Both are the same mistake: a string literal whose length is written out
somewhere else. Full suite green -- base, Tty, Ps, Sock, Fb, Usb, Evdev.
An x86-64 operating system built from xv6, now largely rewritten: SMP,
a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF
rasteriser, and a Linux-numbered syscall ABI.
No history before this point -- the tree was never under version control.
This commit exists so the rename that follows has something to undo to.
