Gustavo Duarte

What Does an Idle CPU Do?

In the last post I said the fundamental axiom of OS behavior is that at any given time, exactly one and only one task is active on a CPU. But if there’s absolutely nothing to do, then what? It turns

How a computer boots up

The previous post described [motherboards and the memory map] memory-map in Intel computers to set the scene for the initial phases of boot. Booting is an involved, hacky, multi-stage affair - fun st

How The Kernel Manages Your Memory

After examining the virtual address layout of a process, we turn to the kernel and its mechanisms for managing user memory. Here is gonzo again: Linux processes are implemented in the kernel as insta

Anatomy of a Program in Memory

Memory management is the heart of operating systems; it is crucial for both programming and system administration. In the next few posts I'll cover memory with an eye towards practical aspects, but wi

Feynman, Challenger Disaster, and Software Engineering

On January 28th, 1986, Space Shuttle Challenger was launched at 11:38am on the 6-day STS-51-L mission. During the first 3 seconds of liftoff the o-rings (o-shaped loops used to connect two cylinders

Lucky to be a Programmer

For the past few weeks I've been working with a fellow developer on a project that required an all-out programming effort. It's done now, so we're back to a regular schedule, but when people hear abo

New Languages Considered Harmful: "Learning new languages is a waste of time."