nexoniarz/SchOS
nexoniarz/SchOS
Watch
1
0
Fork
You've already forked SchOS
 0
Code Issues Pull requests Projects Releases 1 Packages Wiki Activity Actions

SCFF: the live root ships compressed, with Xorg and Window Maker

Browse source 
SCFF, the SchOS Compressed File Format (include/fs/scff.h), is a block
image cut into 128 KB chunks, each its own zstd frame, behind an index.
tools/mkscff writes it from fs-ram.img on every core (-19, 11 s) and
checks each chunk decompresses to itself. The kernel carries the .scff
as its ramdisk and unpacks a chunk the first time a block in it is
read; zero blocks share one page. The kernel and the ISO are the
compressed size, and the root costs memory only for what is touched.
See docs/architecture/scff.md.

zstd 1.5.7 comes from ports/zstd like uACPI: the decoder is compiled
into the kernel at -O2, with a static context and a 64 KB stack of its
own, and mkscff builds the whole library from the same release.

world now has xorg-server, the fbdev and evdev drivers, xinit, Window
Maker, xterm and DejaVu, and /root/.xinitrc runs wmaker. That root is
358 MB, 102 MB as SCFF.

The ISO no longer carries the root a third time as an ISO 9660 tree,
which nothing read. schos.iso: 1389 MB -> 318 MB. El Torito keeps its
own copy of the EFI image, the layout real machines have booted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
This commit is contained in:
Nexoniarz 2026-10-24 21:17:31 +02:00
commit df1394eaa3
18 changed files with 832 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

7
docs/plan/alpine.md
View file

@ -74,6 +74,7 @@ All of it found by running apk:
Xorg installs into it in about a minute. All of it is gone at reboot. Keeping packages needs an installer that writes the root
to a SATA or NVMe disk, and a kernel that finds its root there by the
SchFS GPT type rather than as IDE disk 1.
- Xorg from apk (`xorg-server xf86-video-fbdev xf86-input-evdev`) instead of
the hand port in [xorg.md](xorg.md). The packages install; running them is
the next test.
- Xorg and Window Maker are in `world`, so the image starts with them:
`startx` runs `wmaker` from `/root/.xinitrc`. Mesa brings LLVM with it,
about 200 MB of the 358 MB root; the root ships compressed
([SCFF](../architecture/scff.md)), so that costs about 60 MB of ISO.