SchOS/docs/moving-to-linux.md
Nexoniarz dbb88064c1 docs: correct the layout block, and note what a copy leaves behind
README's layout predated the BIOS/UEFI split. moving-to-linux.md now
says what is gitignored and therefore absent from a clone: dist/ holds
61 MB of upstream tarballs, so copy it or let the build re-fetch them --
make ports verifies each against a known SHA-256 either way.
2026-08-09 17:25:42 +02:00

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<!-- SPDX-License-Identifier: Apache-2.0 -->
# Moving the project to a Linux machine
Written for the move to `/home/nexoniarz/Documents/SchOS` on Fedora 44. Nothing
here is Fedora-specific except the package names.
## 1. Copy the repo
Copy the whole directory, `.git` included. Everything that matters is committed
— 17 commits, no remote — and that includes the project memory, which lives in
`.claude/memory/` precisely so it survives this.
```sh
# whatever transport suits: a USB stick, rsync, scp
rsync -a /path/to/SchOS/ /home/nexoniarz/Documents/SchOS/
cd /home/nexoniarz/Documents/SchOS
git log --oneline | head -3 # should show the same commits
git status # should be clean
```
### What is not in the repo
`build/`, `sysroot/` and `dist/` are all gitignored, so `rsync -a` of the
working tree carries them but a `git clone` would not. Two are worth thinking
about:
- **`dist/`** holds the upstream tarballs — musl, toybox, mksh, the DOOM WADs,
`usb.ids`. 61 MB of other people's release artefacts. Copy it to save the
download, or let the build fetch them again; `make ports` calls `curl` and
verifies each against a known SHA-256, so a re-download is safe either way.
Without a network connection, copy it.
- **`sysroot/`** is assembled by the build.
`build/` and `sysroot/` are ignored and do not need copying — `make` rebuilds
them. **One exception**: `sysroot/bin/` holds musl, toybox and mksh, which
cannot be built on Windows and so were staged there once. On Linux they *can*
be built, so let the build produce them (`make ports`) rather than carrying
stale binaries across. The staged copies predate the SchOS rename anyway —
`sysroot/bin/sh` still contains the symbol `__schunix_tp`.
## 2. Restore the memory
Claude Code keeps per-project memory under a key derived from the project's
absolute path, so it differs per machine:
| | |
|---|---|
| `D:\DEV\SchOS` | `D--DEV-SchOS` |
| `/home/nexoniarz/Documents/SchOS` | `-home-nexoniarz-Documents-SchOS` |
One command puts it where this machine looks:
```sh
tools/posix/memory-sync.sh status # shows both sides, changes nothing
tools/posix/memory-sync.sh import # repo -> ~/.claude/projects/<key>/memory/
```
That writes to
`/home/nexoniarz/.claude/projects/-home-nexoniarz-Documents-SchOS/memory/`.
After a session that learned something, `export` and commit, so the knowledge
travels back:
```sh
tools/posix/memory-sync.sh export && git add -A && git commit -m "memory: ..."
```
## 3. Install the toolchain
```sh
tools/posix/setup-fedora.sh --check # report what is missing
tools/posix/setup-fedora.sh # install it
```
That covers clang, lld, llvm, make, gcc, perl, python3, qemu-system-x86,
edk2-ovmf, xorriso and mtools. See [building.md](building.md) for what each is
for and for the other supported hosts.
**PowerShell is the one thing dnf cannot supply.** `tools/windows/bootcheck.ps1`
is the boot test suite, and `pwsh` runs it on Linux perfectly well — there is
simply no Fedora package. The script prints the two ways to get it. Nothing
else needs it: `make`, `make schfs-check` and `make qemu` all work without.
## 4. Build and check
```sh
make # kernel + root filesystem -> schos.img
make schfs-check # B-tree, object and image suites -- all host-native
make qemu # boot it
```
Two things will behave differently here, both improvements:
- **`make ports` works.** musl, toybox and mksh build from source. On Windows
the build skips them and uses whatever is staged.
- **The SchFS round-trip test runs.** It needs symlinks and hard links, which
Git Bash cannot create, so on Windows it skips with a message. This is the
first machine that can actually exercise that path — worth running early,
since it is the one part of SchFS never yet tested.
## 5. KVM
A Ryzen 7000 has SVM, so QEMU can run at native speed instead of emulating:
```sh
ls -l /dev/kvm # should exist
sudo usermod -aG kvm $(id -un) # if it exists but is not readable
```
Then add `-enable-kvm` to a QEMU command line. It is deliberately **not** the
default in the Makefile: the test suite's timings were established under TCG,
and changing the execution engine underneath them is a variable worth
introducing on purpose rather than by accident.
## 6. UEFI
`make qemu-uefi` boots the UEFI path under OVMF. The Makefile searches the
usual locations for the firmware and Fedora's `edk2-ovmf`
(`/usr/share/edk2/ovmf/OVMF_CODE.fd`) is among them.
Note the open bug before spending time on it: under OVMF the kernel reports
`e820: only 8 MB usable`, because `e820_init` takes the usable run *containing
the kernel* and OVMF puts an ACPI NVS region at 0x800000, genuinely fragmenting
it. The loader's map is correct; the kernel's one-contiguous-run assumption is
BIOS-shaped. The fix is to free each usable region rather than one range, which
touches `kalloc`.
## The hardware, for reference
Fedora 44, Ryzen 5 7000-series, RTX 4050, 16 GB DDR5. Nothing in the build cares
about the GPU — QEMU runs headless for tests and uses its own emulated display
otherwise. The Nvidia driver matters only if you want a QEMU window, and the
`nouveau`/proprietary choice makes no difference to SchOS either way.