Awesome Legacy Code

A curated list of legacy systems with publicly available source code

Contents

• Languages
  • Assembly
  • C and C++
  • Fortran
  • Pascal
  • Python
  • Java
  • Scala
  • JavaScript
  • C#
• Coding Katas (many languages)

Languages

Assembly

• Apollo-11 guidance computer
  • The Ultimate Apollo Guidance Computer Talk
  • Don Eyles walks through lunar module source code
• PDP-10 Incompatible Timesharing System
• Prince of Persia - Apple II version
• MS-DOS - Versions 1.X and 2.0
• Commodore Source Code (BASIC, DOS and KERNEL)
• Spacewar for PDP-1
• QuickDraw and MacPoint
• ET - The Extraterrestrial - Atari 2600
• Microsoft GW-BASIC Interpreter

C

• NCSA Mosaic
• Mozilla (the open sourced version of Netscape Navigator)
• Wolfenstein 3D
• DOOM
• Quake
• Microsoft Word for Windows 1.1a
• Microsoft Windows File Manager (WinFile)
• Various Unix systems archived at the Unix Heritage Society
• notqmail - The repo includes tags for various historical releases
• Zapcc

Fortran

• Colossal Cave Adventure

• NASA STRucture ANalysis (NaStrAn)

  NASA STRucture ANalysis (NaStrAn) is the base of still used code (MSC Nastran and NX Nastran) for analyzing mainly structures (planes, rockets, trains, cars,...). Name is probably also inspired by Fortran=Formula Translating System. Check out the corresponding Wikipedia entry for more information

Pascal

• Adobe Photoshop 1.0.1

Python

• James Webb Space Telescope Quick Look Application - there are many other awesome repositories to explore within the same GitHub organization

Java

• Bad Fruit from Peel & Slice (practice)
• ChartSmart (practice)
• Apache-Solr
• Twitter Search

Scala

• Twitter Algorithm

JavaScript

• Habitica
• Etherpad
• Ghost

CSharp

• Roslyn - C# compilation service
• .NET Foundational Libraries
• .NET runtime (BCL, JIT compiler, GC)

Coding Katas (many languages)

• Tennis
• Expense Report
• Gilded Rose
• trivia