Season's Greetings 2020 — A festive display hack for the PDP-1

This is a virtual DEC PDP-1 emulated in HTML5/JavaScript running a festive "display hacks".

These are the official 2020 Season’s Greetings by Norbert Landsteiner / mass:werk – media environments. The program is implemented in "Macro" assembler code for the PDP-1 (announced in 1959 and shipped in 1961, running here in emulation.)



This is Snowflake, an early 1960s graphics demo for the PDP-1, with an additional text display. While there is a symbol generator available for the PDP-1, not every machine came with this (much like this emulator), so the text display is implemented as a software renderer. However, this is slow. Therefore the program uses an JIT outline compiler for the characters to gain some speed (this was originally developed for my implementation of Computer Space for the PDP-1) and a faster random number generator (RNG) borrowed from Spacewar. While Snowflake on its own is running even too fast with this RNG, it’s still a bit flickery together with the text. In order to reduce this, the number of dots has been reduced for any of the strains which produce the snowflake (6 less per strain), as well.
Alas, there’s still a bit of flicker left. Drawing a dot onto the display is still the major bottleneck for any program on the PDP-1 and this is about as complex as you may get with your graphics.

The program "Another Snowflake" (see the menu on top) shows the pure Snowflake-graphics produced by the Spacewar-RNG.