The two players can also play online while using split screen. This game mode is normally exclusive to the Xbox 360 version of Left 4 Dead and Left 4 Dead 2, but may be accessed in the PC versions if you have a controller for the second player and modify some files.
Serial memory processing - Wikipedia. Serial memory processing is the act of attending to and processing one item at a time. This is usually contrasted against parallel memory processing, which is the act of attending to and processing all items simultaneously. https://en.wikipedia.org/wiki/Serial_memory_processing
2. Data Processing. Data processing is the core function and purpose of a computer system. It is the main reason why a computer is actually a computer. The 'brain' of the computer where data is processed is referred to as the microprocessor. It is also commonly known as the central processing unit (CPU) or accelerated processing unit (APU).