The startup structure is designed for being lightweight and easier to implement on the platforms thox is designed for.
The environment provided by the startup script is composed of two main components:
A standard Lua environment, suited for the current Lua version.
An event-based component cross-platform abstraction.
The startup script boots the system in a component-less state, where no components seem loaded. From there, the system has access to two main functions:
The initial few pulls get attach events for abstract and cold-plug devices, mostly the core bus (see Core bus) which is usually (but not guaranteed to be) device number 0 and its devices including hot-plug buses such as the side bus on ComputerCraft (see ComputerCraft side bus) and the universal bus on OpenComputers (see OpenComputers bus).
It is required for systems started up using these sets of scripts to pull events regularly; if the number of awaiting events exceeds an implementation-specific limit (depending on available memory and eventual DOS countermeasures such as a watchdog), the system might crash.
For power-saving purposes, it is recommended for the system to sleep as much as possible; the startup API design allows this while still being interrupted as soon as an event occurs, within the limits of the current platform’s capabilities.