306 lines
14 KiB
HTML
306 lines
14 KiB
HTML
<!doctype html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Paying It Forward: Documenting your Hardware</title>
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<meta name="description" content="A framework for easily creating beautiful presentations using HTML">
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<meta name="author" content="Sean "xobs" Cross">
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<meta name="apple-mobile-web-app-capable" content="yes">
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<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
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<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
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<link rel="stylesheet" href="css/reveal.css">
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<link rel="stylesheet" href="css/theme/lca2020.css" id="theme">
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<!-- Theme used for syntax highlighting of code -->
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<link rel="stylesheet" href="lib/css/zenburn.css">
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<!-- Printing and PDF exports -->
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<script>
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var link = document.createElement('link');
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link.rel = 'stylesheet';
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link.type = 'text/css';
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link.href = window.location.search.match(/print-pdf/gi) ? 'css/print/pdf.css' : 'css/print/paper.css';
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document.getElementsByTagName('head')[0].appendChild(link);
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</script>
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<!--[if lt IE 9]>
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<script src="lib/js/html5shiv.js"></script>
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<![endif]-->
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<style>
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/*********************************************
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* ZOOM REVERSE TRANSITION (i.e. zoom out)
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*********************************************/
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.reveal .slides section[data-transition=zoomrev],
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.reveal.zoomrev .slides section:not([data-transition]) {
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transition-timing-function: ease;
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}
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.reveal .slides > section[data-transition=zoomrev].past,
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.reveal .slides > section[data-transition~=zoomrev-out].past,
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.reveal.zoomrev .slides > section:not([data-transition]).past {
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visibility: hidden;
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-webkit-transform: scale(0.2);
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transform: scale(0.2);
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}
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.reveal .slides > section[data-transition=zoomrev].future,
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.reveal .slides > section[data-transition~=zoomrev-in].future,
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.reveal.zoomrev .slides > section:not([data-transition]).future {
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visibility: hidden;
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-webkit-transform: scale(16);
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transform: scale(16);
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}
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.reveal .slides > section > section[data-transition=zoomrev].past,
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.reveal .slides > section > section[data-transition~=zoomrev-out].past,
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.reveal.zoomrev .slides > section > section:not([data-transition]).past {
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-webkit-transform: translate(0, 150%);
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transform: translate(0, 150%);
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}
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.reveal .slides > section > section[data-transition=zoomrev].future,
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.reveal .slides > section > section[data-transition~=zoomrev-in].future,
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.reveal.zoomrev .slides > section > section:not([data-transition]).future {
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-webkit-transform: translate(0, -150%);
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transform: translate(0, -150%);
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}
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</style>
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</head>
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<body>
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<!-- Start of main presentation -->
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<div class="reveal">
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<div class="footer">
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<a class="url" href="https://p.xobs.io/lca20-bt/">p.xobs.io/lca20-pif</a>
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<span class="theme">Who’s Watching</span><span class="hashtag"> | #LCA2020</span><span class="twitter"> |
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@linuxconfau</span>
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</div>
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<div class="commentary"></div>
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<div class="slides">
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<section data-background-image="css/theme/lca2019-title-bg-transparent.svg">
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<h2 style="background-color: transparent;">Betrusted: Being Secure</h2>
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<h5 style="background-color: transparent;">That's no Blackberry, it's a chat client!</h5>
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<p align="right">
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<small>bunnie - <a href="https://bunniestudios.com/">https://bunniestudios.com/</a> - @bunnievorpal</small>
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</p>
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<p align="right">
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<small>Tom Marble - <a href="https://info9.net/wiki/tmarble/">https://info9.net/wiki/tmarble/</a></small>
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</p>
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<p align="right">
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<small>Sean Cross - <a href="https://xobs.io/">https://xobs.io/</a> - @xobs</small>
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</p>
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</section>
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<section>
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<section>
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<h2>Xous: Why another kernel?</h2>
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<aside class="notes">
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A big question that gets asked is -- why another kernel? Why don't we just
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put Linux on it and be done with it? Or something else like Minix, TockOS,
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or FreeRTOS?
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</aside>
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</section>
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<section>
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<h2>Betrusted Goals</h2>
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<ul>
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<li><=4 MB RAM</li>
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<li>Process Isolation</li>
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<li>Safe language</li>
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<li class="fragment">Microkernel</li>
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</ul>
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<aside class="notes">
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With Betrusted, we wanted to reduce the code footprint. This will allow
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us to run with less RAM -- ideally 4 MB or less. We also wanted to have
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a full MMU, which is somewhat unusual in the embedded microcontroller
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space, where a more limited Memory Protection Unit is preferred.
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We would like to have full process isolation, so even if one process is
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compromised, attackers will have a harder time boring through the system
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to gain a more complete takeover.
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Therefore, we would like Betrusted to run a Microkernel-style operating
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system, with "servers" that provide features such as the display,
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keyboard, and even basic task switching. These should all run in
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userspace with the bare minimum permissions required to get the job done.
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Finally, we would like to have the operating system written in a safe
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systems language.
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</aside>
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</section>
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<section>
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<h2>Rust: Safety, Speed, Concurrency</h2>
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<aside class="notes">
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The Rust programming language promises the holy trifecta: Safety, Speed,
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Concurrency. Pick any three. If you're going to start over on a systems-
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level project, choose Rust. There will be a lot of wailing and gnashing
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of teeth to begin with, but the end result will be better.
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When we started Betrusted, we decided that it should primarily use Rust
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as the systems language. That way we can be sure that our code is sound.
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Additionally, Rust has the ability to produce efficient binaries, and the
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efficiency is only going to get better as time progresses.
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This eliminates non-Rust choices such as Linux or Minix.
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</aside>
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</section>
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<section>
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<h2>A Survey of Rust-based Operating Systems</h2>
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<aside class="notes">
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Having decided to use Rust, we did a survey of Rust-based operating
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systems. There are several available, in various states of completeness.
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The two biggest candidates are Redox and Tock.
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</aside>
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</section>
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<section>
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<h2>Rust-based Operating Systems: Tock</h2>
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<aside class="notes">
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Tock is the most obvious choice, since it already has a RISC-V port
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and is supported by a well-documented ABI. Tock supports multiple
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tasks written in either Rust or C, which is a very nice feature.
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However, Tock does not support an MMU. It would be possible to adapt
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the MPU interface to work with an MMU, but a lot of design work has
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gone into Tock to make it work well with only the standard MPU that
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is present on most ARM chips. Using Tock would be asking it to do
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something that it's not designed for. Instead, it's better to pick
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the right tool for the job.
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Additionally, the Tock message passing infrastructure assumes only
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one server per process, which can limit flexibility.
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</aside>
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</section>
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<section>
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<h2>Rust-based Operating Systems: Redox</h2>
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<aside class="notes">
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Redox is the other large Rust-based operating system, and is the most
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compelling. Redox is currently limited to x86-64 (with a plan to
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port it to AArch64), so we would need to port it ourselves to RISC-V.
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The biggest problem with Redox is its size: It's a full Desktop
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operating system, and supporting it on Betrusted would require us to
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spend a lot of time cutting it down to just the bare microkernel,
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at which point we can start to recreate everything ourselves. The
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kernel itself is such a small part of Betrusted. Besides, we would
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like the freedom to experiment, to randomize the syscall numbers and
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have keepout areas of the screen and add IMEs to the input, which
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would quickly introduce incompatibility with Redox.
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Finally, we would like to be able to use stable Rust for our applications,
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which we can almost do with Xous. We're just waiting for either the
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"alloc_error_handler" attribute to be stabilized (issue 66740), or
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defaulting handle_alloc_error to panic (issue 66741), which would give
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us everything we'd need to use alloc on stable Rust.
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In short, Tock is too small, and Redox is too big.
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</aside>
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</section>
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<section>
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<h2>Other Alternatives and Inspirations</h2>
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<aside class="notes">
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There are many alternative operating systems. We can draw inspiration
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from them, even if we don't use them directly.
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For example, both the QNX microkernel and Solaris Doors implementation
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allow for one process to pass a message to another, which then inherits
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its remaining quantum and runlevel. This prevents priority inversions
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and makes syscalls relatively cheap.
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</aside>
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</section>
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</section>
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</div>
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</div> <!-- class="reveal" -->
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<!-- End of main presentation -->
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<!-- Start of configuration section -->
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<script src="lib/js/head.min.js"></script>
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<script src="js/reveal.js"></script>
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<script>
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var presenter = !!Reveal.getQueryHash().s;
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// More info https://github.com/hakimel/reveal.js#configuration
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Reveal.initialize({
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controls: presenter ? false : true,
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progress: true,
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history: true,
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center: false,
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controlsTutorial: presenter ? false : true,
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slideNumber: presenter ? null : 'c/t',
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// The "normal" size of the presentation, aspect ratio will be preserved
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// when the presentation is scaled to fit different resolutions. Can be
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// specified using percentage units.
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width: 960,
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height: 700,
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// Factor of the display size that should remain empty around the content
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margin: 0.1,
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multiplex: {
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url: 'https://p.xobs.io/',
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id: '631bb3db6fbaea78',
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secret: Reveal.getQueryHash().s || null
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},
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// Bounds for smallest/largest possible scale to apply to content
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minScale: 0.02,
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maxScale: 5.5,
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transition: 'slide', // none/fade/slide/convex/concave/zoom
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// More info https://github.com/hakimel/reveal.js#dependencies
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dependencies: [
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{ src: 'lib/js/classList.js', condition: function () { return !document.body.classList; } },
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{ src: 'plugin/markdown/marked.js', condition: function () { return !!document.querySelector('[data-markdown]'); } },
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{ src: 'plugin/markdown/markdown.js', condition: function () { return !!document.querySelector('[data-markdown]'); } },
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{ src: 'plugin/highlight/highlight.js', async: true, callback: function () { hljs.initHighlightingOnLoad(); } },
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{ src: 'plugin/search/search.js', async: true },
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{ src: 'plugin/zoom-js/zoom.js', async: true },
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{ src: 'plugin/notes/notes.js', async: true },
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{ src: 'lib/js/socket.io.js', async: true },
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{
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src: presenter ?
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'plugin/multiplex/master.js' :
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'plugin/multiplex/client.js', async: true
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},
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]
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});
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Reveal.addEventListener( 'slidechanged', function( event ) {
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// event.previousSlide, event.currentSlide, event.indexh, event.indexv
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var commentaries = document.getElementsByClassName("commentary");
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Array.prototype.forEach.call(commentaries, cmt => {
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cmt.innerHTML = "";
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});
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// debugger;
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event.currentSlide.childNodes.forEach(element => {
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if ((element.nodeName == "ASIDE") && (element.className == "notes")) {
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Array.prototype.forEach.call(commentaries, cmt => {
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cmt.innerHTML = "<p>" + element.innerHTML.replace("\n\n", "</p><p>") + "</p>";
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});
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}
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});
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} );
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</script>
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</body>
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</html>
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