OpenPeripheralCore Mod 1.7.10 includes common code sets and APIs for mods such as ComputerCraft or OpenComputers mod. That is the reason why this mod will help to enhance your experiences when playing Minecraft. So this is a useful mod that you should not ignore in the future.
About OpenPeripheralCore mod
In fact, this mod will allow to convert many blocks from many mods to ComputerCraft peripherals. This feature will help you to manipulate easily when converting blocks in-game.
Because of being the support mod, it will not have any effect when the individual installed into Minecraft. And of course, this mod also does not add any new content to Minecraft.
The mods that are supported by it usually use the same code structure. So to reduce the file size, save more time, and optimize everything, the author merged this code into this mod. That is the reason why if you do not install this mod before it needs it, it will run and generate an error or failure to load the main menu.
Make sure that you have to install Minecraft Forge if you want the OpenPeripheralCore Mod can work effectively. This is really a useful mod that you should not miss when playing Minecraft. Good luck!