ef94fac4ac
Two additions to docs/Website. **The reader.** docs.html renders the 29 documents in docs/ in the site's own theme -- index down the left, table of contents down the right, and links between documents rewritten so ../history/schfs.md navigates inside the reader instead of downloading a file. The parser is ~150 lines in docs.js, not a dependency: it handles exactly what docs/ uses, and a Markdown library would outweigh every other asset here combined. Everything is escaped before a tag is emitted, so the only HTML that reaches the page is HTML docs.js wrote. Verified by rendering all 30 documents (302 KB of Markdown) with zero failures, no unrestored sentinels and no runaway loops. One caveat, stated in the page itself rather than hidden: browsers block fetch() on file:// URLs, so this page needs a server. It says so, with the command, and offers the raw file as a fallback. The rest of the site is unaffected. **The flag.** A Progress Pride flag in the top bar and a line in the footer, on both pages, permanently. Support with an end date is marketing. It is deliberately small and deliberately not a page of its own -- this is an operating system, and the flag is a statement, not a subject. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2
303 lines
12 KiB
HTML
303 lines
12 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="en">
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
<title>SchOS — a 64-bit operating system written from scratch</title>
|
|
<meta name="description" content="SchOS is a from-scratch x86-64 operating system: the SchIFT kernel, the SchFS copy-on-write filesystem, a UEFI loader, and a userland that runs unmodified musl and toybox.">
|
|
<link rel="icon" href="Assets/shift.svg" type="image/svg+xml">
|
|
<link rel="stylesheet" href="style.css">
|
|
</head>
|
|
<body>
|
|
|
|
<header class="top">
|
|
<div class="wrap">
|
|
<a class="brand" href="#top">
|
|
<img src="Assets/shift.svg" alt="">
|
|
SchOS
|
|
</a>
|
|
<a class="pride" href="#pride-note" title="SchOS stands with the LGBTQIAP+ community — every month of the year">
|
|
<img src="Assets/pride.svg" alt="Progress Pride flag">
|
|
</a>
|
|
<nav>
|
|
<a href="#origin">Origin</a>
|
|
<a href="#stack">The stack</a>
|
|
<a href="#what">What it has</a>
|
|
<a href="#numbers">Numbers</a>
|
|
<a href="docs.html">Docs</a>
|
|
</nav>
|
|
</div>
|
|
</header>
|
|
|
|
<main id="top">
|
|
|
|
<section class="hero">
|
|
<div class="wrap">
|
|
<div>
|
|
<h1><img class="mark" src="Assets/shift.svg" alt="">SchOS</h1>
|
|
<p>
|
|
A 64-bit operating system written from scratch — its own kernel, its own
|
|
filesystem, its own bootloader. It boots on UEFI, drives real hardware,
|
|
and runs unmodified <code>musl</code> and <code>toybox</code> on top.
|
|
</p>
|
|
<div class="cta">
|
|
<a class="btn primary" href="#what">What it has</a>
|
|
<a class="btn" href="#origin">Where it started</a>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="console" aria-label="Boot log">
|
|
<div class="console-bar">
|
|
<i class="dot live"></i> ttyS0
|
|
<span>SchIFT</span>
|
|
</div>
|
|
<pre id="bootlog" aria-live="polite"></pre>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
<section id="origin" class="reveal">
|
|
<div class="wrap">
|
|
<p class="eyebrow">Origin</p>
|
|
<h2>It started as a teaching kernel and stopped being one</h2>
|
|
<p class="lede">
|
|
SchOS began as <a href="https://github.com/mit-pdos/xv6-public">xv6</a>, MIT's
|
|
teaching operating system: 32-bit, single core, one filesystem, a few dozen
|
|
syscalls. Almost none of that survives. What follows is what replaced it.
|
|
</p>
|
|
|
|
<div class="origin-grid">
|
|
<div class="step">
|
|
<span class="when">First</span>
|
|
<h3>64-bit, and more than one core</h3>
|
|
<p>
|
|
Four-level paging, a real SMP bring-up, per-CPU state and a trap path
|
|
that survives both. This is the part that invalidates most of what a
|
|
32-bit uniprocessor kernel assumes.
|
|
</p>
|
|
</div>
|
|
<div class="step">
|
|
<span class="when">Then</span>
|
|
<h3>Its own filesystem</h3>
|
|
<p>
|
|
xv6's log-structured filesystem was replaced by <b>SchFS</b>: a
|
|
copy-on-write B-tree with an uberblock ring, extents and checksummed
|
|
metadata. A crash leaves either the old tree or the new one.
|
|
</p>
|
|
</div>
|
|
<div class="step">
|
|
<span class="when">Then</span>
|
|
<h3>A Linux-shaped ABI</h3>
|
|
<p>
|
|
The syscall table adopted Linux numbering, which is what makes an
|
|
unmodified musl and an unmodified toybox run. The table is one
|
|
<code>.inc</code> file, and it is the seam the whole system is built around.
|
|
</p>
|
|
</div>
|
|
<div class="step">
|
|
<span class="when">Now</span>
|
|
<h3>Hardware, not emulation</h3>
|
|
<p>
|
|
A UEFI loader, xHCI and USB storage, an e1000 with a real TCP/IP stack,
|
|
virtio-gpu and VBE framebuffers, and a device model where a driver never
|
|
names its consumer.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
<section id="stack" class="reveal">
|
|
<div class="wrap">
|
|
<p class="eyebrow">Architecture</p>
|
|
<h2>Two seams hold the whole thing together</h2>
|
|
<p class="lede">
|
|
Above the syscall table, software is ordinary and portable. Below the device
|
|
model, a driver never names its consumer and a consumer never names a driver.
|
|
Everything else is arrangement.
|
|
</p>
|
|
|
|
<div class="stack">
|
|
<div class="layer"><span class="name">userland</span><span class="what">toybox, mksh, musl, and the first-party programs in <code>cmd/</code></span></div>
|
|
<div class="layer"><span class="name">schinit</span><span class="what">PID 1 — job manifests and supervision</span></div>
|
|
<div class="layer seam"><span class="name">syscall table</span><span class="what">Linux numbering, one <code>.inc</code> file — the ABI seam</span></div>
|
|
<div class="layer"><span class="name">kernel services</span><span class="what">VFS, sockets, signals, mmap, poll, procfs</span></div>
|
|
<div class="layer"><span class="name">subsystems</span><span class="what">SchFS, lwIP, text and graphics, the buffer cache</span></div>
|
|
<div class="layer seam"><span class="name">device model</span><span class="what">class vtables and bus binding — the driver seam</span></div>
|
|
<div class="layer"><span class="name">drivers</span><span class="what">xHCI, e1000, virtio-gpu, VBE, IDE, PS/2</span></div>
|
|
<div class="layer"><span class="name">SchIFT core</span><span class="what">scheduler, paging, traps, IRQ, SMP, DMA</span></div>
|
|
<div class="layer"><span class="name">boot</span><span class="what">the UEFI loader in <code>boot/uefi</code></span></div>
|
|
</div>
|
|
|
|
<p class="seam-note">
|
|
<code>uname -s</code> reports <b>SchIFT</b> — the kernel — the way every Unix
|
|
reports its kernel rather than its distribution.
|
|
</p>
|
|
</div>
|
|
</section>
|
|
|
|
<section id="what" class="reveal">
|
|
<div class="wrap">
|
|
<p class="eyebrow">What it has</p>
|
|
<h2>Built and running, and honest about the rest</h2>
|
|
<p class="lede">
|
|
Every card marked <b>runs</b> is in the tree and works today. The tags are
|
|
not aspirational; the things that are not finished say so.
|
|
</p>
|
|
|
|
<div class="cards">
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3><img class="cardmark" src="Assets/uberblock.svg" alt="">SchFS</h3>
|
|
<p>
|
|
Copy-on-write B-tree, a 128-slot uberblock ring, extents with refcounts
|
|
and reflink, CRC32c on metadata, and free space derived from the tree
|
|
rather than stored beside it — so there is no second structure to
|
|
disagree with the first. There is nothing to repair after a crash.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3>SMP x86-64 kernel</h3>
|
|
<p>
|
|
Four-level paging, multiple cores, preemptive scheduling, a calibrated
|
|
LAPIC timer, real signal delivery and job control. 205 syscalls on
|
|
Linux numbering.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3>Networking</h3>
|
|
<p>
|
|
An e1000 driver under lwIP, with sockets for AF_INET, AF_UNIX and
|
|
AF_NETLINK. DHCP brings the interface up at boot; <code>ping</code>
|
|
reaches the outside world.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3>UEFI boot</h3>
|
|
<p>
|
|
A PE/COFF loader built with clang and lld-link that sets up its own page
|
|
tables and hands the kernel a framebuffer. No BIOS path, no chainloading.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3>USB</h3>
|
|
<p>
|
|
xHCI, hubs, HID and mass storage — a keyboard and a USB disk that the
|
|
kernel can mount, through the same device model as everything else.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag runs">runs</span>
|
|
<h3>A real userland</h3>
|
|
<p>
|
|
musl and toybox, both unmodified, plus mksh as <code>/bin/sh</code>.
|
|
<b>fastfetch</b> builds from upstream source with an empty
|
|
<code>patches/</code> directory — when it could not detect something, the
|
|
answer was to give the kernel what it was looking for.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag partial">in progress</span>
|
|
<h3>Schcom</h3>
|
|
<p>
|
|
The compositor that will own the display. v0 runs. The desktop above it
|
|
is the next large piece of work, and it is deliberately Wayland-shaped.
|
|
</p>
|
|
</div>
|
|
<div class="card">
|
|
<span class="tag planned">designed</span>
|
|
<h3>SchAPI</h3>
|
|
<p>
|
|
The native programming interface — specified, not built, and deliberately
|
|
so. It should be designed <i>from</i> the compositor's experience rather
|
|
than before it.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
<section id="numbers" class="reveal">
|
|
<div class="wrap">
|
|
<p class="eyebrow">Numbers</p>
|
|
<h2>The size of it</h2>
|
|
<div class="figures">
|
|
<div class="figure"><b>43,701</b><span>lines in <code>kernel/</code> and <code>include/</code></span></div>
|
|
<div class="figure"><b>205</b><span>syscalls, Linux numbering</span></div>
|
|
<div class="figure"><b>128</b><span>uberblock ring slots</span></div>
|
|
<div class="figure"><b>0</b><span>patches carried against fastfetch</span></div>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
<section class="crash reveal">
|
|
<div class="wrap">
|
|
<img src="Assets/guru.svg" alt="Guru, the SchOS crash-screen icon">
|
|
<div>
|
|
<p class="eyebrow">When it stops</p>
|
|
<h2>PSOGM</h2>
|
|
<p>
|
|
When the kernel panics it does not scroll a stack trace past you. It draws
|
|
a full-screen report — what failed, where, and the state that mattered —
|
|
and encodes the whole thing as a QR code so it can leave the machine
|
|
without being retyped.
|
|
</p>
|
|
<p>
|
|
This purple is <code>#4B1D9A</code>, and the theme reserves it for exactly
|
|
this. Normal states are calm and dark; only failure is loud. It is the one
|
|
colour in the system that means something, which is why it appears once on
|
|
this page and nowhere else.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
<section id="docs" class="reveal">
|
|
<div class="wrap">
|
|
<p class="eyebrow">Reading</p>
|
|
<h2>Where to look</h2>
|
|
<p class="lede">
|
|
The documentation is written to outlive the work. Anything finished is
|
|
described in <code>architecture/</code>; anything intended lives in
|
|
<code>plan/</code>; and the bugs worth remembering are kept in
|
|
<code>history/</code>, in full, including the wrong turns.
|
|
</p>
|
|
<p class="readerlink"><a class="btn primary" href="docs.html">Open the docs reader</a></p>
|
|
<div class="links">
|
|
<a class="link-card" href="docs.html?doc=architecture/README.md">
|
|
<b>Architecture</b><span>What the system is, layer by layer</span>
|
|
</a>
|
|
<a class="link-card" href="docs.html?doc=plan/1.0.md">
|
|
<b>The 1.0 definition</b><span>What is in, what is out, and why</span>
|
|
</a>
|
|
<a class="link-card" href="docs.html?doc=history/kernel.md">
|
|
<b>Kernel history</b><span>The bugs, and what each one taught</span>
|
|
</a>
|
|
<a class="link-card" href="docs.html?doc=guides/building.md">
|
|
<b>Building it</b><span>Toolchain, ports, and running under QEMU</span>
|
|
</a>
|
|
</div>
|
|
</div>
|
|
</section>
|
|
|
|
</main>
|
|
|
|
<footer>
|
|
<div class="wrap">
|
|
<span>SchOS — kernel <b>SchIFT</b>, filesystem <b>SchFS</b>.</span>
|
|
<span class="mono">Apache-2.0, with the xv6-derived core under MIT.</span>
|
|
<span class="pride-note" id="pride-note">
|
|
<img src="Assets/pride.svg" alt="">
|
|
Built by, and for, people of every orientation and gender identity.
|
|
The flag stays up all year.
|
|
</span>
|
|
</div>
|
|
</footer>
|
|
|
|
<script src="app.js"></script>
|
|
</body>
|
|
</html>
|