CPU

The [blank_start]central processing unit (CPU)[blank_end] of a computer is the hardware that executes programs and manages the rest of the hardware. Think of the CPU as the brain of the computer. Just as your brain contains parts that remember things, parts that think and parts that make the rest of your body operate, the [blank_start]CPU[blank_end] does the same for the computer. The CPU is made up of the [blank_start]main memory[blank_end], the [blank_start]processor[blank_end] and the cache memory (we’ll talk about the cache later). The program instructions and data move between the main memory and the processor using internal connections called [blank_start]system buses[blank_end].

When a program is to be run (executed) on a computer it fi rst has to be loaded into the [blank_start]main memory[blank_end]. From here it can be accessed by the processor, which runs each [blank_start]instruction[blank_end] in turn. When the program is loaded, the processor is given the start address of where the program is held in main memory. To run the program the processor [blank_start]fetches[blank_end] an instruction, [blank_start]decodes[blank_end] it and then [blank_start]executes[blank_end] it. The processor executes one instruction at a time. This is called the [blank_start]fetch-execute cycle[blank_end].

When we looked at the basic [blank_start]fetch-execute[blank_end] cycle we assumed that there was a [blank_start]single[blank_end] processor and a single main memory. You have probably heard terms like “[blank_start]dual[blank_end]-core” and “[blank_start]quad[blank_end]-core” so where do these fi t in? Today’s more complex CPUs can include more than one [blank_start]processor[blank_end], or core. A dual-core processor has [blank_start]two[blank_end] processing components within the CPU. A quad-core, likewise, has [blank_start]four[blank_end]. In theory having two processors means that the computer can operate twice as fast but this isn’t always the case.

Label the image with the correct name of the CPU cycle and each part of the cycle

Label the components of a computer system