Official documentation of OpenComputers

OpenComputers is a mod that adds computers and robots into the game, which can be programmed in Lua 5.3. It takes ideas from a couple of other mods such as ComputerCraft, StevesCarts and Modular Powersuits to create something new and interesting.


OpenComputers can connect to and interact with the outside Minecraft world through several methods:

Most of OpenComputers' blocks can “see” and interact with other OpenComputers Blocks automatically if placed right next to each other, or you can use Cables to connect them over a distance. It is also possible to connect - or separate - components logically by using one of the various network cards or switches in both wired and/or wireless form.

Blocks from Vanilla or other Mods can be connected via the Redstone Card, the Redstone I/O Block or an Adapter. Many special Blocks from other mods are already integrated into the Adapter, like Blocks from BuildCraft, IndustrialCraft2 or Thermal Expansion, other mods authors can use the Java API to add specific handling for their blocks as well.

Robots can interact with the world almost like a real player can do. They can equip most tools, blocks or other items and can be programmed to use them in every way you want them to. You can program them to sort your inventory, go mining for your resources, have them build a fortress for you or make them sing and dance for your entertainment. Only your imagination is the limit.

See the page on component interaction to learn how to communicate with components from Lua.


OpenComputers are built out of individual parts such as graphic cards, hard drives or expansion cards, which allows to tailor each individual computer exactly to your needs. You can save resources if you need something small for small tasks, or spend even the last diamond on the most expensive and powerful Minecraft computer ever built.

See the block and item documentation for a list of components that can be used to assemble your computer.

Resource Limits

OpenComputers have a limited amount of disk space and RAM, which can be configured in the OpenComputers config to your likings. This not only makes OpenComputers very server friendly, it as well gives you a warm feeling of nostalgia, back at a time where disk and RAM size was measured in Kilo and Megabytes. However as programming in Lua is very resource-friendly, you should be able to solve most tasks even on mid-end OpenComputers. And if not you could always spend some diamonds on even bigger RAM.

In addition to those intuitive limitations, OpenComputers has been specifically designed to work flawlessly on servers: OpenComputers uses a fixed number of low-priority threads for coroutines to cause as little delay on the server tick as possible, in addition running programs are forced to yield on a regular, configurable basis or - if for any reason fail to do so - will crash (the in-game computer) forcefully to prevent server lag by malicious or malfunctioning programs.


When OpenComputers leave the loaded Chunk area, they will be put on hold, but automatically resume at the exact point they were stopped once the Chunk is reloaded later. This makes OpenComputers very intuitive to use in the Minecraft environment, as you do not have to worry about chunk loading or resuming and do not need to add chunk loaders from other mods just to keep those computers running.

To do so OpenComputers comes with a native library - the Eris library, specifically. This includes the official Lua VM implementation, which is already capable to support computers being put on pause temporarily. Currently the library is included in the mod for Windows, Mac OS X, Linux and BSD, which are only required to run on the server as all Lua code is executed purely on the server. If the library is not available for your system, the mod will fall back to LuaJ, a Java implementation of Lua, in which case computers will not persist, and memory will not be limited.


Computers consume power while running based on what they are doing. Beside a low base amount of power per tick consumed, components such as graphic cards or wireless network cards will consume extra power based on their work load. This is not only realistic, but as well encourages players to optimize their code and to not keep an OpenComputers server busy with unnecessary tasks. The exact power consumption can be configured in the config file and even be completely removed if you wish to run in a power-free environment.

OpenComputers mod provides electrostatic power generation with Carpeted Capacitor as well as with Generator Upgrade available to robots and Solar Generator Upgrade available to robots and microcontrollers. Opencomputers devices can also be powered with energy equivalents of a number of other mods.


Almost every aspect of the mod can be tweaked via the configuration file. Not a fan of computers requiring power to run? Set their running cost to zero. Don't want power to play a role at all? Disable it completely! Think robots move too slow? Make 'em faster. Want bigger multi-block screens? Increase the maximum size. Just have a look at the default configuration file to see all the options.


Addon Mods Addons Computronics
Supporting OpenComputers Thut's Concrete