Introduction

The Asterisk Gateway Interface, commonly referred to as AGI, is a language-independent API for processing calls. It allows programmers to write simple programs to manipulate and route calls on Asterisk servers in a simple, easy manner.

This article provides a technical introduction to the AGI, explaining how it works, how it can be used, where you can find API documentation, and even provides some basic code samples which demonstrate how to use the AGI. The intended audience is programmers, telephony enthusiasts, or IT people who want to learn more about adding functionality to their Asterisk PBX systems. This is not a full programming reference, and will not explain how to write AGI programs, it will merely teach you what the AGI provides and how to use it high-level.

A few days back I ordered a copy of Scott Chacon's book: Pro Git, which I am really enjoying reading. Scott is an excellent writer, and really does justice to Git. I was reflecting on his enthusiasm, and thinking about my own. Here are my thoughts on Git, and my experience with it over the years.

I started using Git around 2 years ago when I saw a screencast discussing it online. What initially drew me to Git was that it was created by Linus (who was very enthusiastic about it), and that my previous experiences with version control systems (VCS) were horrible. Naturally, I wanted to give it a try, and get back to the best-practices way of doing things (using a VCS).

When I first learned about VCSs, pretty much everyone used SVN or CVS. When I researched them both, there was no doubt in my mind that SVN was clearly the most popular, and so that's what I decided to learn. I started using SVN for all of my code (most of it was hosted on Sourceforge at some point or another), and learned it well enough to push periodic updates to my projects and do basic collaboration with a few other people.

Introduction

Hashing normally makes people think of cryptographic hashing often used to store passwords. Understandable considering this is what users might more familiar with. However, the principles of hashing are used for more than simply preventing retrieval of certain data.

What I'm referring to is hashing for the purposes of efficient data referencing. This is better known to developers rather than users.