1. The CPU GapFill

The CPU, known also as the capital clock central control processing unit, or simply the processor, is the component responsible for performing calculations and executing instructions.

Several components are common to any CPU, and each component has a clearly defined role.  The arithmetic logic unit (ALU) is responsible for performing calculations.  These might take the form of performance relational arithmetic Boolean operations, such as addition and subtraction, arithmetic Boolean primary relational operations such as OR and NOT, and standard performance arithmetic relational operations, such as less than or greater than.

The ALU will perform such calculations only when instructed to do so by the critical unit central unit command unit control unit , which manages the execution of instructions, as well as the flow of data through the CPU.

In addition to these components, there is also a collection of registers that form part of the CPU.  A register is a small (typically 64 bits nibbles gigabytes megabytes for a modern PC) but quick-to-access storage area, each of which can store a single piece of information.  There are multipurpose generalised general-purpose specialised registers, whose behaviour will vary depending on the nature of the program being run, and special-purpose registers, which each have a clearly defined role.

Special-purpose registers include the program counter memory buffer register memory address register memory data register , which at the beginning of each cycle contains the buffer address counter colour of the next instruction to be accessed, as well as the memory address register, which can point to memory locations of instructions or data.  The subtotal accumulator program counter adder is a register that stores intermediate results of calculations, meaning partially calculated results.

Components both within and beyond the CPU are interconnected using buses.  The data bus secondary bus address bus primary bus is used to transmit memory locations; the data bus primary bus address bus secondary bus is used to transmit, among other things, program instructions between memory and the CPU; the secondary bus control bus data bus primary bus is used when the CPU needs to issue a command to memory, such as 'read' or 'write'.

In order for the behaviour of the various CPU components to be synchronised, the pulsar timer multiplexor clock sends out a pulse on a regular basis – typically billions of times per second.  A task can be commenced only as one of these pulses take place, although multiple pulses may occur before a task is completed.