Small and portable input device with functions for starting and controlling document display

An input device being selected from a group consisting of a mouse and a keyboard, the input device comprising:

• a cover;
• a plurality of keys arranged on an external surface of the cover;
• a circuit board arranged in the cover;
• a storage unit coupled to the circuit board, the storage unit storing a computer operating system of a computer and a preset document, the computer operating system having a micro-computer architecture and executing a part of function of the standard computer operating system when executed;
• a first communication unit coupled to the circuit board, the first communication unit configured to enable the input device to communicate with an external display device;
• and
• a processor coupled to the circuit board, the processor configured to generate a starting signal when a first preset condition is met, execute the computer operating system of the computer and the preset document in the computer operating system according to the starting signal, and display the executed preset document on the external display device via the first communication unit.