Central processing unit  (Processing Device)

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The term has been used in the computer industry at least since the early 1960s.^[1] Traditionally, the term "CPU" refers to a processing unit, or processor, and itscontrol unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.^[2]

The form, design and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations,processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and "executes" them by directing the coordinated operations of the ALU, registers and other components.

Data Process (computing)

In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently.

A computer program is a passive collection of instructions; a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often means more than one process is being executed.

Multitasking is a method to allow multiple processes to share processors (CPUs) and other system resources. Each CPU executes a single task at a time. However, multitasking allows each processor to switch between tasks that are being executed without having to wait for each task to finish. Depending on the operating system implementation, switches could be performed when tasks perform input/output operations, when a task indicates that it can be switched, or on hardware interrupts.

A common form of multitasking is time-sharing. Time-sharing is a method to allow fast response for interactive user applications. In time-sharing systems, context switches are performed rapidly. This makes it seem like multiple processes are being executed simultaneously on the same processor. The execution of multiple processes seemingly simultaneously is called concurrency.

Data processing

Data processing is, broadly, "the collection and manipulation of items of data to produce meaningful information." In this sense it can be considered a subset of information processing, "the change (processing) of information in any manner detectable by an observer."

The term is often used more specifically in the context of a business or other organization to refer to the class of commercial data processing applications.

Manual data processing

Although widespread use of the term data processing dates only from the nineteen-fifties data processing functions have been performed manually for millennia. For examplebookkeeping involves functions such as posting transactions and producing reports like the balance sheet and the cash flow statement. Completely manual methods were augmented by the application of mechanical or electronic calculators. A person whose job it was to perform calculations manually or using a calculator was called a "computer."