Computer Case

A Computer Case is a type of block from OpenComputers. It is the core component of all non-Server computers and holds important computer parts, such as the Central Processing Unit (CPU) and Memory.

In order to run, a Computer Case must be supplied with power generated by a Power Converter, and must have a functioning EEPROM installed. The preprogrammed Lua BIOS is sufficient in most cases, it will check for a file named init.lua in the root directory of all connected file systems, and execute the first one it finds. Writing custom EEPROMs is only useful in advanced use cases, such as when writing a custom operating system. (In earlier mod versions lacking the ability to write custom EEPROMs, all Computer Cases ran the Lua BIOS.)

OpenComputers comes with a built-in operating system named OpenOS, which can be programmed onto a Floppy Disk by combining it with a Book in a crafting grid. By default the OpenOS floppy disk is read-only; in order to make modifications or permanently store files the operating system must be copied to a Hard Disk Drive. This is most easily done by running the install command from the OpenOS shell.

Tooltip Description[edit]

The Computer Case is the basic building block for computers and houses the computer's extension cards, RAM and hard disks.


Currently there are four Computer Case tiers available. Each tier provides more and more advanced component slots, allowing for construction of more advanced and complex computers. The last tier of Computer Case cannot be crafted and is only obtainable in Creative Mode or using cheats and can only be accessed by players in Creative Mode.

Computer Case CPU Slots Memory Slots Card Slots Hard Disk Slots Floppy Drives Energy Conversion Rate
Computer Case (Tier 1) Computer Case (Tier 1) 1 × Tier 1 2 × Tier 1 2 × Tier 1 1 × Tier 1 None 5 units/tick
Computer Case (Tier 2) Computer Case (Tier 2) 1 × Tier 2 2 × Tier 2 1 × Tier 2
1 × Tier 1
1 × Tier 2
1 × Tier 1
None 10 units/tick
Computer Case (Tier 3) Computer Case (Tier 3) 1 × Tier 3 2 × Tier 3 1 × Tier 3
2 × Tier 2
1 × Tier 3
1 × Tier 2
1 × 20 units/tick
Computer Case (Creative) Computer Case (Creative) 1 × Tier 3 2 × Tier 3 3 × Tier 3 2 × Tier 3 1 × 9001 units/tick
Has a built-in infinite power supply