Process States, Threads and the POSIX Threads Library

The five process states and their transitions, what a thread owns and shares, the TCB, pthread_create/join/exit, and why two threads on a counter lose updates.

2026, Sep 16   —  21 minute read

The Process Control Block, fork/exec/waitpid/exit and the Context Switch

What a Process Control Block holds, how fork(), exec(), waitpid() and exit() create, replace and reap processes, and what a context switch costs the kernel.

2026, Sep 16   —  20 minute read

File Descriptors, the IPC Subsystem and Pipes - Named, Anonymous and Shell Pipelines

How descriptor tables point into the kernel open-file table, what dup2() redirects, the IPC families, and how pipe(), fork() and exec() build ls | more.

2026, Sep 16   —  23 minute read

Packing Small Values into One Field on Aztec — The Packable Trait, Its Cost and Its Traps

A derived Packable spends one Field per member. Packing two bools into one saves a slot or a note-hash input, can cost gates, and moves every slot after it.

2026, Sep 16   —  22 minute read

Code Reuse in Aztec Contracts — Modules, Traits and Library Crates Instead of Inheritance

Aztec contracts cannot inherit. What a contract module must own, what a Noir library can hold, and how a trait replaces virtual methods, on a two-variant token.

2026, Sep 15   —  25 minute read

The FRI Toolbox in Twelve Cards — The Definitions to Memorise

Twelve flashcards for the toolbox FRI is built from: Reed-Solomon codes, rate, the Johnson bound, IOPs of proximity, quotienting, DEEP, proximity gaps and folding.

2026, Sep 14   —  10 minute read

FRI Explained Like I'm Ten — How to Check a Million Numbers by Peeking at Twenty

A plain-language guide to FRI and proximity proofs. Secret rules, smudged lists, sealed notebooks, a division trick and paper folding, with worked examples.

2026, Sep 14   —  18 minute read