what is a processor in a computer. what is a central processing unit (cpu, cpu). how does a central processor work? what processor architectures are
We are well aware of the main components of a computer, but few people understand what the processor consists of. Meanwhile, this is the main device of the system, which performs arithmetic and logical operations.
The main processor function is to obtain information, process it and return the final result. It all sounds simple, but in fact this process is complicated.
- Processor definition
- what is the consists of processor
- how does the processor work?
- Basic concepts of processor in computer science
- What is turbo boost in the processor
- Main processor specifications what is the processor speed
- CPU and graphics card temperature
- Types of processors
- How to overclock the processor
- how the processor works: command processing
- CPU possible problems
- von neumann architecture
- conveyor architecture
Processor (microprocessor, CPU, central processor, accelerator – stone, percent, etc.) – we can say the heart of the computer, the brain, its main part. It processes information, executes all user commands and controls the rest of the devices of the system unit. The processor power determines how fast the computer will work.
The processor is mounted on the motherboard and placed in a special socket, which is called the socket of the central processor (socket, eng. – socket). There are many types of sockets, in each of them you can install a “stone” only its own specific type. Installing the motherboard into the socket must be done very carefully, otherwise the contacts may be damaged and the “percent” will be damaged.
what is the consists of processor
A CPU is a miniature rectangular silicon wafer that contains millions of transistors (semiconductors). They implement all the functions that the processor performs.
Almost all modern processors consist of the following components:
- Several cores (rarely 2, usually 4 or 8) that perform all processor function. In essence, the core is a separate miniature processor. Several cores integrated into the main chip work on tasks in parallel, which speeds up the data processing. However, not always more cores mean faster chip operation.
- Several levels of cache memory (2 or 3), due to which the time of interaction between RAM and the processor is reduced. If the information is in the cache, then the access time to it is minimized. Therefore, the larger the cache volume, the more information will fit into it and the faster the processor will be.
- RAM controller and system bus.
- Registers – memory cells where the processed data is stored. They always have a limited size (8, 16 or 32 bits).
- Coprocessor. A separate kernel that is designed to perform operations of a certain type. Most often, the graphic core (video card) acts as a coprocessor.
- The address bus that connects the chip to all devices connected to the motherboard.
- Data bus – for communication between the processor and RAM. In essence, a bus is a set of conductors through which an electrical signal is transmitted or received. And the more conductors there are, the better.
- Synchronization bus – allows you to control the clock cycles and frequency of the processor.
- Restart bus – resets the state of the chip.
All these elements take part in the work. However, the most important among them, of course, is the core. All other specified components only help him perform the main task. Now that you understand what the processor consists of, you can examine its main component in more detail.
If we talk about how the Intel processor or its competitor AMD works, you need to see how these chips work. The first microprocessor (incidentally, namely from Intel, model 4040) appeared back in 1971. It could perform only the simplest operations of addition and subtraction with processing only 4 bits of information, i.e., it had a 4-bit architecture.
Modern processors, like the first-born, are based on transistors and have much greater speed. They are made by photo lithography from a certain number of individual silicon wafers that make up a single crystal into which transistors are imprinted. The circuit is created on a special accelerator with accelerated boron ions. In the internal structure of processors, the main components are cores, buses, and functional particles called revisions.
CPU main characteristics
Like any other device, the processor is characterized by certain parameters, which, when answering the question of how the processor works, cannot be ignored. First of all, this:
- Number of Cores;
- number of threads;
- cache size (internal memory);
- clock frequency;
- tire speed.
For now, let’s dwell on the clock frequency. No wonder the processor is called the heart of the computer. Like the heart, it works in pulsation mode with a certain number of beats per second. Clock frequency is measured in MHz or GHz. The higher it is, the more operations the device can perform.
At what frequency the processor works, you can find out from its declared characteristics or see the information in But during the processing of commands, the frequency can change, and during overclocking (overlocking) increase to extreme limits. Thus, the claimed is only an average indicator.
The number of cores – an indicator that determines the number of processor centers in the processor (not to be confused with threads – the number of cores and threads may not coincide). Due to this distribution, it becomes possible to redirect operations to other kernels, thereby increasing overall performance.
Speaking of what the central processor consists of, first of all it is necessary to mention the kernels, since they are the main parts of it.
Kernels include function blocks that perform arithmetic or logical operations. In particular, we can distinguish:
- Block sampling, decoding and executing instructions.
- Block for saving results.
- Command counter block, etc.
As you understand, each of them performs a specific task. For example, the instruction fetch unit reads them at the address specified in the instruction counter. In turn, the decoding blocks determine what the processor needs to do. Together, the work of all these blocks allows us to achieve the task specified by the user.
The processor core problem
Note that cores can only perform mathematical calculations and comparison operations, as well as move data between RAM cells. However, this is enough for users to play games on the computer, watch movies, and browse the web.
In fact, any computer program consists of simple commands: add, multiply, move, divide, go to the instructions when the condition is met. Of course, these are just primitive commands, but combining them together allows you to create a complex function.
What does the processor consist of besides cores? Registers are its second important component. As you already know, these are fast memory cells where the processed data is located. They are different:
- A, B, C – are used to store information during processing. There are only three of them, but this is enough.
- EIP – this register stores the address of the next instruction in the queue.
- ESP – data address in RAM.
- Z – here is the result of the last comparison operation.
The processor is not limited to these registers. There are others, however, the above are the most important – they are most often used by the chip to process data during the execution of a program.
Multi core processors
what are good? The use of such processors is comparable to the use of several separate processors for one computer. The cores are in the same chip, they are not completely independent (for example, use a shared cache). When using existing software that was originally created to work with a single core, this option gives a tangible plus. You can run simultaneously two (or more) resource-intensive tasks without the slightest discomfort. However, the acceleration of a single process – the task for these systems is virtually impossible. As a result, we get almost the same single-core processor with a slight plus in the form of the ability to use several programs simultaneously.
The way out of this delicate situation is quite obvious – it requires the development of a new generation of software that can use several cores simultaneously. It is necessary to parallelize processes somehow. In reality, it turned out to be very difficult. Of course, some tasks are probably quite easy to parallelize. For example, it is relatively easy to parallelize video and audio encoding.
Here, the basis is a set of threads of the same type, respectively, to organize their simultaneous execution is a fairly simple task. The gain of existing multi-core processors in solving coding problems before “similar” single-core ones will be proportional to the number of these cores: if two cores, then twice as fast, four cores four times, 6 cores six times. Unfortunately, the overwhelming majority of important tasks are much more difficult to parallelize. In most cases, serious code processing is required.
Already several times, representatives of fairly powerful computer companies have heard joyful statements about the successful development of original multi-core processors of a new generation, which are able to independently separate one thread into a group of independent threads, but, unfortunately, none of them has yet demonstrated a single similar working model.
The steps of computer companies towards mass use of multi-core processors are very obvious and straightforward. The main task of these companies is to improve processors, create new promising multi-core processors, maintain sound pricing policies aimed at lowering prices (or restraining their growth). Today, in the middle segment of the two leading world computer giants (AMD and Intel) you can see a very wide variety of dual-core and quad-core processors.
If desired, you can find even more sophisticated options. The good news is that developers of modern software themselves begin to take an important step towards the user. Many recent games have already acquired support for two cores. The most powerful of them is practically vital to a minimum of a dual-core processor to ensure and maintain optimal performance.
Looking around the shelves of the best computer stores, analyzing the state of affairs with the assortment, we can say that the overall picture is not bad at all. Manufacturers of multi-core processors managed to achieve a very high level of production of suitable crystals. Their pricing policy is quite reasonable. At current prices, it can be seen that, for example, doubling the number of processor cores usually does not double the price of such a processor for a buyer. This is very reasonable and quite logical. In addition, it is quite clear to many that with an increase in the number of cores of the central processor by a factor of two, productivity on average does not increase by the same amount.
Nevertheless, it is worth recognizing that, despite the thorny path to creating even more advanced multi-core processors, there is simply no alternative to it in the near foreseeable future. Ordinary consumers who want to keep up with the times can only modernize their computer in a timely manner, using new processors with an increased number of integrated cores, bringing overall performance to a higher level in this way. Various single-core processors are still successfully used in mobile phones, netbooks and other equipment.
The central processor is the brain and heart of the computer
The word processor itself comes from the English verb to process, In a general sense, this term refers to a device or set of programs that are used to perform computational operations or process a data array or process.
In a personal computer, the processor performs the function of the “brain”, being the main chip that is required for the smooth and proper operation of the PC. Under the control of the CPU are all internal and peripheral devices.
Externally, the processor is a small square board, the upper part of which is closed by a metal cover, which serves to protect microcircuits, and the lower surface is strewn with a large number of contacts. It is on this side that the processor is installed in a special socket or socket located on the motherboard. The CPU, or central processing unit, is the most important part of a modern computer. Without a command that the CPU gives, there is not a single, even the simplest, operation, for example, adding two numbers or writing one byte of information.
how does the processor work?
The principle of the processor is the sequential processing of various operations. They occur very quickly, the main ones:
- When starting any process involving the execution of program code, the CPU control unit extracts all the necessary data and a set of operands required for execution. Then it is shipped to the buffer or cache memory.
- At the exit from the cache, the entire flow of information is divided into two categories – instructions and values. They are redirected to the appropriate memory cells, called registers. The first are placed in the command registers, the second category – in the data registers.
- The information in the memory registers is processed by an arithmetic-logical device. This is one of the parts of the CPU that is required for arithmetic and logical operations.
- The calculation results are divided into two streams – finished and incomplete, which, in turn, are sent back to the cache.
- At the end of the cycle of calculations, the final result is written into RAM. This is required to free up space in the buffer, which is necessary for new computational operations. When the cache overflows, all inactive processes are moved to RAM or to the lower level.
The buffer memory is virtually divided into two parts – the lower and upper levels. Active processes are located on the upper “floor”, and unimportant operations are moved to the lower level. If necessary, the lower layers of information are used by the system, the rest of the time the data is not involved. This approach allows the processor to use all resources for the current operation.
what is a processor socket
The term socket translates from English as “socket” or “connector”. For a personal computer, this term simultaneously refers directly to the motherboard and processor. A socket is a CPU mount. They differ among themselves by such characteristics as size, number and type of contacts, and features of the cooling installation.
The two largest manufacturers of processors – Intel and AMD – are waging a long-standing marketing war, offering each their own socket, suitable only for the CPU of its production. The number in the marking of a particular socket, for example, LGA 775, indicates the number of contacts or contact legs. Also, in technological terms, sockets can vary among themselves:
- the presence of additional controllers;
- the ability of technology to support the graphics core of the processor;
A socket can also affect the following computer settings:
- type of supported RAM;
- FSB bus operating frequency
- indirectly, on the PCI-e version and SATA connector.
Creating a special socket for mounting the central processor is required so that the user can upgrade the system and change the CPU in case of failure.
A processor socket is a socket for installing it on a motherboard.
The graphics core in the processor: what is it
One of the details of the CPU, in addition to the main core itself, can be a graphics processor. What is it and what is the use of such a component for? It should be noted right away that embedding the graphics core is optional and is not present on every processor. This device is required to perform the basic functions of the CPU in the form of solving computational problems, as well as graphics support.
Sometimes you can find the abbreviation IGP, which stands for Integrated Graphics Processor or integrated graphics processor. This means that in this particular PC, a similar solution is used, and a discrete graphics card may be completely absent.
The reasons why manufacturers use the technology of combining two functions in one core are:
- Reduced energy consumption as smaller devices require less power and cooling costs
- cost reduction.
The use of integrated or integrated graphics is most often observed in laptops or inexpensive PCs designed for office work, where there are no excessive requirements for graphics.
The graphics core is a graphics co-processor delivered to the CPU
Basic concepts of processor in computer science
what are threads in processor
The thread of execution in the CPU is the smallest unit of processing that is assigned by the kernel, necessary to separate the code and the context of the executable process. At the same time, there may be several processes that simultaneously use CPU resources. There is an original development of Intel, which began to be used in models starting with the Intel Core i3 processor, which is called Hyper Threading. This is a technology for dividing a physical core into two logical ones. Thus, the operating system creates additional computing power and increases threading. It turns out that only an indicator of the number of cores will not be decisive, since in some cases computers with 4 cores lose in speed to those that have only 2
what is the process technology in the processor
Under the technical process in computer science refers to the size of the transistors used in the computer core. The manufacturing process of the CPU occurs by the method of photo lithography, when transistors are etched from the crystal coated with a dielectric film under the influence of light. The optical equipment used has such an indicator as resolution. This will be the technological process. The higher it is, the more transistors can fit on a single chip.
Reducing the size of the crystal contributes to:
- reduction of heat and energy consumption;
- performance, since while maintaining the physical size of the crystal, it is possible to place more work elements on it.
The technological process unit is a nano meter (10-9). Most modern processors are manufactured using a 22 nm process.
An example is the Intel Core i7 processor, which with a crystal size of 160 mm contains 1.4 billion work elements.
A technological process is an increase in the number of working elements of a processor while maintaining its size.
What is processor virtualization
The basis of the method is to divide the CPU into the guest and monitor part. If switching from the main to the guest OS is required, then the processor automatically performs this operation, keeping visible only those register values that are required for stable operation. Since the guest operating system interacts directly with the processor, the virtual machine will be much faster.
Enabling virtualization is possible in the BIOS settings. Most motherboards and processors from AMD do not support virtual machine technology using hardware methods. Here, software methods come to the aid of the user.
What are processor registers
The processor register is a special set of digital electrical circuits that relate to the ultra fast memory needed by the CPU to store the results of intermediate operations. Each processor contains a great many registers, most of which are inaccessible to the programmer and reserved for the execution of the core functions of the kernel. There are general and special purpose registers. The first group is available for circulation, the second is used by the processor itself. Since the speed of interaction with CPU registers is higher than the memory access, they are actively used by programmers to write software products
What is processor capacity
Each user of Windows OS when installing new programs was faced with the choice of a version for the system capacity. What is the capacity of the CPU? In simple terms, this is an indicator, otherwise called a machine word, showing how many bits of information the CPU processes in one clock cycle. In modern processors, this indicator can be a multiple of 32 or 64.
for a typical user, the bit rate indicator will determine the maximum amount of RAM that is supported by the processor. For 32 bits it is 4 GB, and for 64 bits the upper limit is already 16 TB.
What is processor throttling
Throttling, or throttling, is a protective mechanism that is used to prevent the CPU from overheating or causing hardware malfunctions during operation. The function is active by default and works when the temperature rises to a critical point, which is set for each specific model of CPU by the manufacturer. Protection is achieved by reducing kernel performance. When the temperature returns to normal values, the function is automatically disabled. There is a possibility to force change throttling parameters through BIOS. It is actively used by fans of overclocking the CPU or overclockers, but for a simple user, such changes are fraught with damage to the PC.
what is processor scalping
Processor scalping is the procedure for removing the cover to replace thermal grease. This procedure is one of the components of overclocking or may be required to reduce the load on the hardware of the CPU.
The procedure itself is:
- removing the cover;
- removal of old thermal paste;
- crystal cleaning;
- applying a new layer of thermal paste;
- closing the lid.
During the procedure, one should take into account the fact that one incorrect movement can lead to processor failure. Therefore, it is better to entrust this event to professionals. If the decision to scalp at home is made completely, then we can advise you to purchase a special device in the form of a clamp for the CPU, which will facilitate the removal of the lid without damaging the crystal.
What is turbo boost in the processor
Turbo Boost is Intel’s proprietary technology used in the first three generations of Intel Core i5 and i7 processors. It is used to hardware accelerate the CPU for a certain time. Using technology, the acceleration procedure is carried out taking into account all important parameters – current strength, temperature, voltage, OS state, therefore it is completely safe for the computer.
The increase in processor speed is temporary and will depend on the type of load, the number of cores and platform configuration. In addition, it should be noted that the technology is supported only by the operating systems Windows 7 and 8.
Intel proprietary technology allows you to temporarily improve computer performance
Main processor specifications what is the processor speed
Many users have heard such a thing as clock speed, but not everyone fully understands what it is. In simple terms, this is the number of operations that the CPU can perform in 1 second. Here the rule applies – the higher the measure of tact, the more efficient the computer.
The unit of measurement of the clock frequency is Hertz, which in its physical sense is a reflection of the number of oscillations over a specified period of time. The formation of clock oscillations occurs due to the action of a quartz crystal, which is located in the clock resonator. After the voltage is applied, an electric current oscillation occurs. They are transmitted to a generator, converting them into pulses, which are sent to the data bus. The processor clock speed is not the only characteristic for evaluating the speed of a PC. You also need to consider the number of cores and the amount of buffer memory.
CPU and graphics card temperature
When the kernel and other CPU elements work, a large amount of heat is released, which is why modern computers use powerful cooling systems, both of the central processor and the main components of the motherboard. Demanding programs that actively use the power of the CPU and video card (usually games) load the processor, which leads to a rapid increase in temperature. In this case, throttling is turned on. Many video card manufacturers claim that their products are able to function normally even at 100 ° C. In reality, the limit temperature will be that specified in the technical documentation.
powerful video cards and processors operate at higher clock frequencies, which leads to greater heat dissipation. Therefore, they require improved cooling
You can independently control the temperature regime through special monitoring software (AIDA64, GPU Temp, Speccy). If there is a slowdown during work or play, it means that it is likely that the temperature has risen to a critical point and the protection has automatically triggered.
You can independently monitor the temperature of the CPU and video card through special software
Types of processors
In total, it is customary to distinguish 5 main types of processors in a computer:
- Buffer . This is the coprocessor that is required for preprocessing information between peripherals and the CPU.
- Preprocessor . At its core, it is similar to the previous processor, the purpose of which is intermediate data processing.
- CISC . CPU manufactured by Intel, which differs from the usual in an increased set of instructions.
- RISC . An alternative version of CISC with a reduced number of teams. Most large processor manufacturers work on a combination of two varieties (CISC and RISC), which will increase the power and speed of the kernel.
- Clones . These are processors that are produced by small manufacturers under license or in a completely pirated way.
The most popular CPU models and manufacturers
The market of microprocessors is divided by two large manufacturers – Intel and AMD, which have been fighting an irreconcilable struggle throughout their entire existence. Each company offers its own turnkey solutions. The choice of a specific model is the subjective decision of the end user, since each manufacturer offers a wide range of models that have both budget options and top-end gaming CPUs.
The most popular in the line of processors from Intel are Intel Core i3, i5 and i7 models. Depending on the modification, they can be used both in gaming PCs and in office machines. At AMD, Ryzen series processors are considered to be one of the best, demonstrating good performance indicators. Athlon series is still found, but refers to the archival. For an undemanding user, AMD A series processors are suitable. AMD and Intel are the two largest processor companies
How to overclock the processor
Overclocking, or overclocking the central processor, may be advisable in the presence of outdated equipment and the lack of funds to buy a new stone. Typically, the procedure allows you to get a performance increase of 10 to 20%. There are two methods for overclocking – by increasing the FSB frequency or increasing the processor multiplier. Modern computers, as a general rule, come with a locked multiplier, so the most affordable way will be to change the frequency of the system bus.
Overclocking the processor by increasing the frequency of the bus or processor multiplier
Basic overclocking tips:
- Touching the core nutrition in the absence of experience is not recommended.
- The increase in the frequency indicator should be carried out in stages, increasing at a time by no more than 100 MHz.
- Monitor the temperature, as heat increases as the frequency increases.
- When deciding to increase the core power, the step is 0.05V, while the maximum limit should not exceed 0.3V, otherwise the CPU is likely to fail.
- After each increase, it is required to test stability. At the first failures, overclocking must be stopped.
if at reaching the maximum frequency there is stable operation, but excessive heating, in this case it is necessary to fully study the operation of the PC cooling system.
The overclocking process can be simplified through the use of special programs that independently control the main parameters that are affected during overclocking.
The processor is the heart of your PC. This is where the administration of all the processes of the machine. The quality of the entire computer depends on how efficiently this unit works. And that means that your confidence and calm completely depend on the choice of high-quality filling of a hardware-computer machine.
Almost everyone knows that in the computer, the main element among all the “hardware” components is the central processor. But the circle of people who imagine how the processor works is very limited. Most users have no idea about this. And even when the system suddenly starts to “slow down”, many people think that this processor does not work well and do not attach importance to other factors. To fully understand the situation, consider some aspects of the CPU.
how the processor works: command processing
Now a little about the structure of executable commands. If you look at how the processor works, you need to clearly imagine that any command has two components – operational and operand.
The operating part indicates what the computer system should perform at the moment, the operand determines what the processor should work on. In addition, the processor core may contain two computing centers (containers, streams) that divide the execution of the command into several stages:
- command execution;
- memory access to the processor itself
- saving the result.
Today, separate caching is used in the form of using two levels of cache memory, which helps to avoid interception by two or more teams of access to one of the memory blocks.
Processors according to the type of instruction processing are divided into linear (execution of instructions in the order of their writing), cyclic and branching (execution of instructions after processing branch conditions).
Operations in progress
Among the main functions assigned to the processor, in the sense of executed commands or instructions, three main tasks are distinguished:
- mathematical operations based on arithmetic logic device;
- moving data (information) from one type of memory to another;
- making decisions on the execution of the command, and on its basis – the choice of switching to the execution of other sets of commands.
Memory interaction (ROM and RAM)
In this process, components such as a bus and a read and write channel that are connected to the storage devices should be noted. ROM contains a constant set of bytes. First, the address bus requests a specific byte from the ROM, then transfers it to the data bus, after which the read channel changes its state and the ROM provides the requested byte.
But processors can not only read data from RAM, but also write them. In this case, the recording channel is used. But, if you look, by and large, modern computers could theoretically do without RAM, since modern microcontrollers are able to place the necessary data bytes directly in the memory of the processor chip itself. But there is no way to do without ROM.
Among other things, the start of the system is started from the equipment testing mode (BIOS command), and only then control is transferred to the loaded operating system.
CPU possible problems
Finally, a few words about the problems. Here, many users often ask, they say, why does the processor work, but the monitor does not turn on? This situation has nothing to do with the central processor. The fact is that when you turn on any computer, the graphics adapter is tested first, and only then everything else. Perhaps the problem lies precisely in the processor of the graphics chip (all modern video accelerators have their own graphical processors).
But on the example of the functioning of the human body, one must understand that in the event of a cardiac arrest, the whole organism dies. So with computers. The processor does not work – the whole computer system “dies”.
The central processor ( CPU ) – the executor of machine instructions, part of the hardware of a computer or programmable logic controller, responsible for performing operations specified by programs.
Modern CPUs, executed in the form of separate microcircuits (chips) that implement all the features inherent in this kind of devices, are called microprocessors. Since the mid-1980s, the latter have virtually supplanted other types of CPUs, as a result of which the term has become more and more often perceived as an ordinary synonym for the word “microprocessor”. However, this is not so: the central processing units of some supercomputers even today are complex complexes of large (LSI) and super-large (VLSI) integrated circuits.
Initially, the term Central Processing Unit described a specialized class of logical machines designed to execute complex computer programs. Due to the rather exact correspondence of this purpose to the functions of computer processors existing at that time, it was naturally transferred to the computers themselves. The beginning of the use of the term and its abbreviation in relation to computer systems was laid in the 1960s. The device, architecture, and implementation of processors have since changed repeatedly, however, their main functions are the same as before.
Early CPUs were created as unique components for unique, and even one-of-a-kind, computer systems.
Later, from an expensive way to develop processors designed to run one single or several highly specialized programs, computer manufacturers switched to serial production of typical classes of multipurpose processor devices.
The trend towards standardization of computer components originated in the era of rapid development of semiconductor elements, mainframes and minicomputers, and with the advent of integrated circuits, it became even more popular.
The creation of microcircuits allowed us to further increase the complexity of the CPU while reducing their physical size.
The standardization and miniaturization of processors has led to the deep penetration of digital devices based on them into everyday life.
Modern processors can be found not only in high-tech devices such as computers, but also in cars, calculators, mobile phones, and even in children’s toys.
Most often they are represented by micro controllers, where in addition to the computing device, additional components are located on the chip (interfaces, input / output ports, timers, etc.).
The modern computing capabilities of the micro controller are comparable to the processors of personal computers of a decade ago, and often even significantly exceed their performance. mobile phones and even in children’s toys.
Most often they are represented by microcontrollers, where in addition to the computing device, additional components are located on the chip (interfaces, input / output ports, timers, etc.).
von neumann architecture
Most modern processors for personal computers are generally based on a particular version of the cyclic process of sequential information processing, invented by John von Neumann.
D. von Neumann came up with a scheme for building a computer in 1946.
The most important steps in this process are listed below. In different architectures and for different teams, additional steps may be required. For example, arithmetic instructions may require additional memory access, during which the operands are read and the results written. A distinctive feature of von Neumann architecture is that instructions and data are stored in the same memory.
Stages of the execution cycle:
- The processor sets the number stored in the register of the command counter to the address bus, and gives the read command to the memory;
- The set number is the memory address; the memory, having received the address and the read command, sets the contents stored at this address to the data bus, and reports readiness;
- The processor receives the number from the data bus, interprets it as a command (machine instruction) from its command system and executes it;
- If the last command is not a jump instruction, the processor increases by one (assuming that the length of each instruction is equal to one) the number stored in the instruction counter; as a result, the address of the next command is formed there;
- Again, item 1 is satisfied.
This cycle is carried out invariably, and it is called the process (where the name of the device came from).
During the process, the processor reads the sequence of instructions contained in the memory and executes them. Such a sequence of commands is called a program and represents an algorithm of useful processor operation. The order of reading commands changes if the processor reads a jump command – then the address of the next command may turn out to be different. Another example of a process change is when a stop command is received or when a hardware interrupt is processed.
Central processor commands are the lowest level of computer control, so the execution of each command is inevitable and unconditional. No check is made on the admissibility of the performed actions, in particular, the possible loss of valuable data is not checked. In order for the computer to perform only permissible actions, the commands must be properly organized in the form of the necessary program.
The rate of transition from one stage of the cycle to another is determined by the clock. The clock generates pulses that serve as the rhythm for the central processor. The frequency of clock pulses is called the clock frequency.
Pipelined architecture ( pipelining ) was introduced in the CPU to improve performance. Typically, to execute each command, it is necessary to carry out a certain number of operations of the same type, for example: fetching a command from RAM, decrypting a command, addressing an operand in RAM, fetching an operand from RAM, executing a command, writing the result to RAM. Each of these operations is associated with a single conveyor stage. For example, a microprocessor pipeline with MIPS-I architecture contains four stages:
- receiving and decoding instructions (Fetch)
- addressing and fetching operand from RAM (Memory access)
- Arithmetic Operation
- saving the result of an operation (Store)
After releasing the k- th stage of the conveyor, she immediately begins work on the next team. If we assume that each stage of the pipeline spends a unit of time on its work, then executing a command on a pipeline of length n steps will take n units of time, however, in the most optimistic case, the result of each next command will be obtained every unit of time.
Indeed, in the absence of a pipeline, the execution of a command will take n units of time (since to execute a command, it is still necessary to perform sampling, decryption, etc.), and to execute m commands, it will take units of time; when using the pipeline (in the most optimistic case), to execute m commands, it will take only n + m units of time.
Factors that reduce conveyor efficiency:
- a simple conveyor, when some steps are not used (for example, addressing and selecting an operand from RAM are not needed if the command works with registers);
- expectation: if the next command uses the result of the previous one, then the last one cannot start executing before the first one is executed (this is overcome when using extraordinary execution of commands, out-of-order execution);
- cleaning the pipeline when a transition command gets into it (this problem can be smoothed out using transition prediction).
Some modern processors have more than 30 steps in the pipeline, which increases processor performance, but leads to a large downtime (for example, in case of an error in predicting a conditional transition.)
Now you know what the processor consists of and which modules are the main ones. A similar composition of the chips is not constant, as they are gradually being improved, new modules are added, old ones are improved. However, today what the processor consists of, its purpose and functionality are exactly as described above.
The composition and approximate principle of operation of processor systems described above are simplified to a minimum. In fact, the whole process is more complex, but to understand it you need to get the appropriate education.
An important question from users, which I put off for later, what is the processor in the computer? Central processing unit (CPU) is the most important part of the hardware of any computer, responsible for performing the necessary arithmetic operations specified by programs, coordinating the work of all, without exception,.
Of course, the processor is the heart of every computer. It is the processor that executes the instructions of the software used on the personal computer, processes the data set, and performs complex computational operations. The main characteristics of the processor are: performance, clock speed, power consumption, architecture and cache.
So, you and I understood what a processor is, but what are the types and what is the purpose of a processor in a computer? Let’s, first things first. It is known that processors are single-core and multi-core . A multi-core processor is a central processor that contains two (or more) processing cores located on one small processor chip or in one common package. A regular processor has only one core. The era of single-core processors is gradually becoming a thing of the past. By their characteristics, they, in general, lose to multi-core processors.
For example, the clock speed of a mediocre dual-core processor can often be much lower than the frequency of a good single-core processor, but due to the division of tasks into “both heads”, the difference in results becomes insignificant. The dual-core Core 2 Duo processor with a clock frequency of 1.7 GHz can easily outperform a single-core Celeron with a clock frequency of 2.8 GHz, because the performance depends not only on the frequency, but also on the number of cores, cache and other factors.
At present, two major processor manufacturers are leading the world computer market – Intel Corporation (its share today is about 84%) and AMD (about 10%). If you look at the history of the development of central processors, you can see quite a lot of interesting things. Since the advent of the first desktop computers, the main way to improve performance has been to systematically increase the clock speed.
This is very obvious and logical. However, there is a limit to everything and the frequency cannot be increased indefinitely. Unfortunately, with an increase in frequency, heat release begins to increase nonlinearly, reaching ultimately critically high values. So far, even the use of more subtle technical processes in the creation of transistors does not help to solve this problem.
Is there a way out of this very difficult situation? Soon, a solution was found in the use of several nuclei in one crystal. It was decided to apply the “2 in 1” processor option. The appearance on the market of computers with such processors has caused a number of disputes. Do I need multi-core processors? Why are they better than conventional processors with a single core? Maybe manufacturing companies just want to get extra profit? Now we can confidently answer: multi-core processors are needed, the future lies with them. In the coming decades, it is impossible to imagine progress in this industry without the use of multi-core processors.