what-happens-when
QEMU
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what-happens-when | QEMU | |
---|---|---|
76 | 190 | |
38,680 | 9,277 | |
- | 2.8% | |
0.0 | 10.0 | |
6 days ago | 4 days ago | |
C | ||
- | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
what-happens-when
- What-Happens-When: An attempt to answer an age-old interview question
- What Happens When
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We have used too many levels of abstractions and now the future looks bleak
Agreed!
It reminds me of:
https://github.com/alex/what-happens-when
and how many of today’s CS-degree holders would barely understand any of it. As someone who has also “grown up with all the technology”, I’ve learned and experienced all that. But as a percentage of “software engineers”, there’s fewer and fewer that do every day.
- Step-by-step events when Browsing www.facebook.com after computer bootup.
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I just blew my interview!
There is a pretty comprehensive answer to number 2 here
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Are you skeptical about candidates that call themselves a "10x engineer"?
Ask them to describe what happens when you visit a website and grill them on every layer of abstraction, every implementation detail.
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You and me Anon, you and me
This is a classic interview question and it basically means "How does internet work?" It is great because it allows to check how many levels of understanding it a developer has. The answer may be quite lengthy, for example: https://github.com/alex/what-happens-when
- Any course that actually teaches me how a website is built?
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I have a question about subdomains and their DNS resolution
Perhaps you will find https://github.com/alex/what-happens-when useful.
- Tried and true interview questions/tasks
QEMU
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QEMU Version 9.0.0 Released
My most-wanted QEMU feature: https://github.com/qemu/qemu/commit/a2260983c6553
Using `gic-version=3` on macOS you can now use more than 8 cores on ARM chips.
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Autoconf makes me think we stopped evolving too soon
A better solution is just to write a plain ass shell script that tests if various C snippets compile.
https://github.com/oilshell/oil/blob/master/configure
https://github.com/oilshell/oil/blob/master/build/detect-pwe...
Not an unholy mix of m4, shell, and C, all in the same file.
---
These are the same style as a the configure scripts that Fabrice Bellard wrote for tcc and QEMU.
They are plain ass shell scripts, because he actually understands the code he writes.
https://github.com/qemu/qemu/blob/master/configure
https://github.com/TinyCC/tinycc/blob/mob/configure
OCaml’s configure script is also “normal”.
You don’t have to copy and paste thousands of lines of GNU stuff that you don’t understand.
(copy of lobste.rs comment)
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WASM Instructions
Related:
A fast Pascal (Delphi) WebAssembly interpreter:
https://github.com/marat1961/wasm
WASM-4:
https://github.com/aduros/wasm4
Curated list of awesome things regarding WebAssembly (wasm) ecosystem:
https://github.com/mbasso/awesome-wasm
Also, it would be nice if there was a WASM (soft) CPU for QEMU, which (if it existed!) would go here:
https://github.com/qemu/qemu/tree/master/target
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Revng translates (i386, x86-64, MIPS, ARM, AArch64, s390x) binaries to LLVM IR
> architectural registers are always updated
In tiny code, the guest registers (global TCG variables) are stored in the host's registers until you either call an helper which can access the CPU state or you return (`git grep la_global_sync`). This is the reason why QEMU is not so terribly slow.
But after a check, this also happens when you access the guest memory address space! https://github.com/qemu/qemu/blob/master/include/tcg/tcg-opc... (TCG_OPF_SIDE_EFFECTS is what matters)
But still, in the end, it's the same problem. What QEMU does, can be done in LLVM too. You could probably be more efficient in LLVM by using the exception handling mechanism (invoke and friends) to only serialize back to memory when there's an actual exception, at the cost of higher register pressure. More or less what we do here: https://rev.ng/downloads/bar-2019-paper.pdf
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State of x86-64 emulation of non-MacOS binaries
Um, in case you don't know, UTM (based on QEMU) is out for quite a while.
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Multipass: Ubuntu Virtual Machines Made Easy
Some of these tools include Oracle VM VirtualBox (that I've used since before the acquisition of Sun Microsystems by Oracle), VMWare Workstation Player, and QEMU, but last year, I found out about Multipass.
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Libsodium: A modern, portable, easy to use crypto library
For C/C++ projects that use meson as the build system, there is an excellent way to manage dependencies:
https://mesonbuild.com/Wrapdb-projects.html
https://mesonbuild.com/Wrap-dependency-system-manual.html
meson will download and build the libraries automatically and give you a variable which you pass as a regular dependency into the built target:
https://github.com/qemu/qemu/tree/005ad32358f12fe9313a4a0191...
https://github.com/harfbuzz/harfbuzz/tree/main/subprojects
https://github.com/harfbuzz/harfbuzz/blob/37457412b3212463c5...
Or, if you're using proper operating systems, they're managed by the usual package manager, just like everything else.
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Top 6 Virtual Machine Software in 2023
For all the users of the Linux platform, QEMU is the VM that you should go for. This software comes without any price tag and works as an emulator of various machines with utmost ease and completion; the software uses dynamic translations to emulate hardware peripherals and enhances its overall performance. If you are using QEMU as a virtualizer, then it will function exactly like the host system (provided you have the right set of hardware).
- Show HN: I'm 17 and wrote this guide on how CPUs run programs
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UTM for Developers
In this tutorial, we set up macOS and Windows virtual machines on UTM, a macOS application that provides a GUI wrapper for QEMU, a powerful open-source emulator and virtualizer. UTM allows you to easily manage and run virtual machines without memorizing complex commands. It also has special handling for macOS, making it simpler to install compared to other virtual machine software.
What are some alternatives?
tianocore
UTM - Virtual machines for iOS and macOS
Essentials-of-Compilation - A book about compiling Racket and Python to x86-64 assembly
TermuxArch - Experience the pleasure of the Linux command prompt in Android, Chromebook, Fire OS and Windows on smartphone, smartTV, tablet and wearable https://termuxarch.github.io/TermuxArch/
scrcpy - Display and control your Android device
Unicorn Engine - Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, PowerPC, RiscV, S390x, TriCore, X86)
sre-interview-prep-guide - Site Reliability Engineer Interview Preparation Guide
Vagrant - Vagrant is a tool for building and distributing development environments.
www.submarinecablemap.com - Comprehensive interactive map of the world's major operating and planned submarine cable systems and landing stations, updated frequently.
xemu - Original Xbox Emulator for Windows, macOS, and Linux (Active Development)
linux-insides - A little bit about a linux kernel
em-dosbox - An Emscripten port of DOSBox