What Are Intros

Intros are known in the demoscene as being demos with a limited size. Often having special compos for them at different demoparties. The most popular size constraint for intros is 64kb, 4kb and 1kb.

On certain platforms other size limitations are also popular (16kb on Atari, 40kb on Amiga).

On the MS-DOS platform intros of 512 bytes, 256 bytes and 128 bytes are also quite popular. Intros that are less than 1 kilobyte are commonly called “bytetros” and are typically coded in pure assembler as opposed to most 1kb to 20kb intros. To get more insight on bytetros you can check other websites such as 256b.com (down since 2007) or the more recently created sizecoding.org.

From the Old school PC demoscene FAQ:

A Demo is a program that displays a sound, music, and light show, usually in 3D. Demos are very fun to watch, because they seemingly do things that aren’t possible on the machine they were programmed on. Essentially, demos “show off”. They do so in usually one, two, or all three of three following methods:

Demos are an art form. They blend mathematics, programming skill, and creativity into something incredible to watch and listen to.