Posts tagged computers

LLVM IR optimization overview for a toy program

:: computers, compilers

In my compilers class this semester we’ve been talking about static analysis and optimizations. We’ve written a little LLVM frontend compiler for a toy language with s-expression (lisp) syntax. We’ve also added an option to our compiler to add arithmetic overflow and division error checks to the compiler output. We’re going to look at the output of this compiler with arithmetic checks on a toy program, and see what the optimizer does to it.

Botnet or Pulseaudio

:: computers, networking

The other day I was sitting at home when I realized that my network switch was going crazy. The switch in question is a gigabit switch that is connected to my home server (which is my home’s gateway device — the one connected to the modem), to a wireless router, and to a desktop machine that acts as a media box (it’s connected to a TV and stereo system). By “going crazy” I mean that all the lights were flashing as fast as they could. There is a light for each connected device, and when it flashes it means that that device is either sending or receiving data — meaning that in this case packets were going to or from my server, my media box, and my wireless router (which by proxy means my laptop, my phone, my wife’s phone, etc) apparently about as fast as possible. Recently there have been some high profile DDOS attacks by botnets of unprecidented size. “Am I part of a botnet?”, I wondered. “Did I make some serious security mistake, despite generally being much more careful than average about security?”.

IPv6 setup

:: ipv6, computers, technical

Some time ago I was finally in a position where my ISP had IPv6 capabilities and I was in full control of my internet setup (IE it wasn’t controlled by landlords or shared with roommates who had stronger opinions than mine). So naturally I decided to join the internet of the future (that should have been the internet of the 90’s) and get IPv6 set up.

Why I hate emojis

:: rant, computers

I have often voiced disdain for emojis, and my unhappiness that they are taking an ever-growing section of the Unicode space. Let me tell you why.

configuration tips

:: introductory, technical, computers

As an avid computer configurator, I want to share some tips about how to effectively customize and keep track of your configuration. I want to highlight the different types of configuration needs that exist, and suggest some good ways of managing them.

pc bios or why smartphones are lame

:: introductory, computers, bios, smart-devices

Today, let me tell you a story about the PC BIOS. Or, why smartphones are lame. I will explain to you why the PC BIOS (and its successor, EFI or UEFI, which I will treat as equivalent for this post) is awesome, and why systems lacking something like a BIOS are lame (generally so-called “smart” devices).