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blog/content/posts/04-printing-to-screen/index.md

@@ -189,6 +189,7 @@ If the byte is the [newline] byte `\n`, the writer does not print anything. Inst
 When printing a byte, the writer checks if the current line is full. In that case, a `new_line` call is required before to wrap the line. Then it writes a new `ScreenChar` to the buffer at the current position. Finally, the current column position is advanced.
 
 The `buffer()` auxiliary method converts the raw pointer in the `buffer` field into a safe mutable buffer reference. The unsafe block is needed because the [as_mut()] method of `Unique` is unsafe. But our `buffer()` method itself isn't marked as unsafe, so it must not introduce any unsafety (e.g. cause segfaults). To guarantee that, it's very important that the `buffer` field always points to a valid `Buffer`. It's like a contract that we must stand to every time we create a `Writer`. To ensure that it's not possible to create an invalid `Writer` from outside of the module, the struct must have at least one private field and public creation functions are not allowed either.
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 [as_mut()]: https://doc.rust-lang.org/nightly/core/ptr/struct.Unique.html#method.as_mut
 
 ### Cannot Move out of Borrowed Content
@@ -646,17 +647,21 @@ Now that you know the very basics of OS development in Rust, you should also che
 
 - [Rust Bare-Bones Kernel]: A basic kernel with roughly the same functionality as ours. Writes output to the serial port instead of the VGA buffer and maps the kernel to the [higher half] \(instead of our identity mapping).
 _Note_: You need to [cross compile binutils] to build it (or you create some symbolic links[^fn-symlink] if you're on x86_64).
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 [Rust Bare-Bones Kernel]: https://github.com/thepowersgang/rust-barebones-kernel
 [higher half]: http://wiki.osdev.org/Higher_Half_Kernel
 [cross compile binutils]: ./posts/cross-compile-binutils/index.md
 
 - [RustOS]: More advanced kernel that supports allocation, keyboard inputs, and threads. It also has a scheduler and a basic network driver.
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 [RustOS]: https://github.com/RustOS-Fork-Holding-Ground/RustOS
 
 - ["Tifflin" Experimental Kernel]: Big kernel project by thepowersgang, that is actively developed and has over 650 commits. It has a separate userspace and supports multiple file systems, even a GUI is included. Needs a cross compiler.
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 ["Tifflin" Experimental Kernel]:https://github.com/thepowersgang/rust_os
 
 - [Redox]: Probably the most complete Rust OS today. It has an active community and over 1000 Github stars. File systems, network, an audio player, a picture viewer, and much more. Just take a look at the [screenshots][redox screenshots].
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 [Redox]: https://github.com/redox-os/redox
 [redox screenshots]: https://github.com/redox-os/redox#what-it-looks-like