The central processor - the whole head
The operation of any computer is provided by oneA small device (chip), which is called the central processor. It is a silicon substrate with layers deposited on it, containing structural elements: an arithmetic logic device (for data processing), a control device (for determining the order of execution of instructions), registers (for data storage), internal cache memory (to accelerate the exchange with the operational memory), an internal bus (for transferring information between the functional parts of the processor), etc.
The central processor, or rather its clockfrequency, determines the speed of the entire system. The clock frequency ensures synchronization, i.e. the consistency of the actions of individual blocks inside the processor and beyond. In modern processors for personal computers, this characteristic is a unit of gigahertz (GHz), which means that it is capable of performing several billion elementary operations in one second. Also, the main characteristics of the processor include bit depth, the amount of internal cache memory, the number of cores, and the socket.
To ensure a given performancecomputer in the first place, you need to select the correct CPU. Let's consider this device in more detail. Types of processors differ in internal architecture, for example, allocate pipeline and superscalar processors. The first increase the productivity by dividing the process of executing commands into separate stages, while the processor simultaneously processes several commands at different stages simultaneously. The more stages at the conveyor, the higher the clock speed and, accordingly, the performance. But only within reasonable limits.
Superscalar processors using severalcomputing cores, can parallelize the execution of the program, but this requires software that will allow the code to be divided into separate threads that can run in parallel. In this case, the presence, for example, of two cores inside the processor does not guarantee a doubling of the performance, because not every program can break into two equivalent streams, not to mention four or eight threads.
The CPU is named so becauseis the main computing device in the computer, but not the only one. In addition, there are controllers of various devices and interfaces in the system, as well as processors for processing video, audio, etc.
Initially, the computer was conceived and createdonly as a device for computing, so the central processor was "responsible" for all the processes in the system: input of information, processing (mathematical transformations), output of information. Now users are more and more tuned to other kinds of information, such as text, graphics, video, sound. Therefore, the central processor gradually lost the all-encompassing zone of influence that belonged to him alone, and shared responsibility with other computing devices.