The computer is made up of system block and peripheral devices (monitor, mouse, keyboard). In this entry, I would like to disassemble the computer in detail to each bolt, consider the computer device as a whole, what it has and why each detail is needed.
System unit
The system unit is the computer itself. The system unit contains: PSU (power supply unit), HDD ( HDD), motherboard, RAM, processor, sound card, video card, LAN card, disk drive and other accessories that are necessary to expand the capabilities. Let's now take a closer look at each device and find out what function it performs.
Case of the system unit
Cases are different: compact, transparent, backlit, but its main task is to fit all the computer devices. Of course, one could do without him, hang motherboard on the wall, and put everything else next to the table, but this is stupid, inconvenient and dangerous.
During the included system unit, in no case should you touch its components. High voltage passes inside, which can even kill. Therefore, the case is always used, it is convenient and safe.
PSU - Power Supply
Almost all the wires that are in the computer come from the power supply. It provides each device in the system unit with electricity, without which nothing will work. The PSU weighs about a kilogram, and is about the size of a .
The power supply outputs: 3.3v, 5v and 12v. For each device a separate voltage. Also, so that the power supply does not overheat, it is equipped with a heatsink and a cooling fan. This is where the sound of a working computer comes from.
Motherboard
The main task of the motherboard is to unite ALL devices of the computer. It will literally unite everything: mouse, keyboard, monitor, USB drives, HDD, processor, video card and everything else. You can find more information about the holes / connectors and ports of the motherboard in the picture above.
CPU - the central processing unit of a computer
The processor provides and calculates all operations on the computer. Compared to human organs, a computer processor can be compared to the brain. The more powerful the chip (CPU), the more calculations it can do, in other words: the computer will run faster. But this is only one of the main devices responsible for the speed of your computer.
RAM - random access memory
RAM is a random access memory. It is also called RAM, random access memory and RAM. This small board is needed to store temporary data. When you copy something, this information is temporarily stored in RAM, it also stores information system files, programs and games. The more tasks you set for your computer, the more RAM it will need. For example, at the same time the PC will download something, play an audio file and the game will be launched, then there will be a large load on the RAM.
The more RAM, the better and faster the computer works (as is the case with the processor).
Video card (video adapter)
A video card, also called a video adapter, is necessary to transfer an image from a computer to a screen / monitor. As mentioned above, it is inserted into the mat. board into your slot.
In general, the computer is designed in such a way that each device has its own hole and even by brute force it is impossible to insert something out of place.
The more complex the image (HD video, game, graphical shell and editor), the more memory the graphics card should have. For example, 4k. the video will not play normally on a weak video card. The video will slow down, and you might think that the Internet is weak.
A modern video card also contains a small cooler (cooling fan) as a PSU and CPU cooling. Under the cooler is a small graphics processor that works like a central processing unit.
HDD (hard disk drive)
HDD - it is also: hard disk, hard, hard drive, screw, drive. No matter how people call him, he has one task. It stores all information and files. Including OS (operating system), programs, browsers, photos, music, etc. In other words, this is the computer's memory (like a flash drive in a phone).
Also there is more SSD. The essence and principle is the same, but the SSD works many times faster and costs an order of magnitude more expensive. If you use an SSD as a system disk for the OS, then your computer will run much faster.
Drive
If you need to view/copy information from a disk, then you will need a disk drive. Nowadays, you rarely see this device in new computers; USB drives (flash drives) have replaced the drive. They take up much less space than discs, are easier to use, and are reusable. Nevertheless, disk drives are still used, and I could not help but write about it.
Sound card
Your computer needs a sound card to play audio files. Without it, there will be no sound in the computer. If you go back to the "motherboard" section for a second, you will see that it is already built into every motherboard.
As you can see in the photo above, there are additional sound cards. They are necessary to connect more powerful speakers and provide better sound, unlike integrated (built-in).
If you are using ordinary small speakers, then the difference will not even be noticeable. If you have a subwoofer or home theater, then of course you need to put a decent sound card.
Computer accessories
Everything I have said above necessary for the operation of the system unit, and now let's look at additional computer devices that expand its capabilities and add functionality.
External hard drive
Unlike an HDD, an external hard drive is portable. If the HDD and SSD need to be installed in the case and fixed there, then the external one is connected with just one USB wire. This is very convenient for all occasions that do not make sense to describe. External HDD It's like a flash drive, only with more memory.
Uninterruptable power source
Absolutely every computer is afraid of power surges, I would even say more than any other technique. Source uninterruptible power supply will provide a stable voltage and save your PSU from surges.
Voltage can jump for various reasons, and it is not always noticeable. For example, if you have weak wiring, then when you turn on other appliances in the house, the voltage may jump. Or the neighbors have something powerful ... In general, I strongly recommend that everyone use an uninterruptible device.
TV tuner
A TV tuner is a special chip that allows you to watch TV on your computer. Here, rather, as in the case of the drive, it still works, but is no longer relevant. To watch TV on a computer, it is not necessary to insert special boards, we now have and on my blog there is a whole section dedicated to this topic.
Computer Peripherals
As wikipedia says:
Peripherals are hardware that allows information to be entered into or output from a computer. Peripherals are not required for the operation of the system and may be disconnected from the computer.
But, I don't agree with her. For example, without a monitor, we don’t even need a computer, and without a keyboard, not everyone can turn on a computer, only the most experienced users can do without a mouse, and you won’t watch or listen to anything without speakers. These are far from all devices, so let's look at each of them separately.
Personal computer monitor
I repeat a little - we do not need a computer without a monitor, otherwise we will not see what is happening there. Perhaps in the future they will come up with some kind of hologram or special glasses, but so far this is just my sick fantasy).
The monitor is connected to the video card with a special cable, of which there are 2 types of VGA (an obsolete connector) and HDMI. HDMI provides best picture, and also transmits sound parallel to the image. So, if your monitor has built-in speakers and has a high resolution, you definitely need to use an HDMI cable.
Keyboard
The keyboard is needed to enter information, call commands and perform actions. Keyboards are different: regular, silent, multimedia and gaming.
- Ordinary - the simplest keyboard, on which there are only standard buttons.
- Silent - rubber / silicone keyboards, when working with which no sound is heard.
- Multimedia. In addition to the standard buttons, the keyboard has additional keys for controlling audio / video files, volume, touchpad (possibly), and the rest.
- Gamer - Additional buttons for different games, the main buttons for the game have a different color and other goodies.
Mouse
The main task of a computer mouse is to control / move the cursor on the screen. Also select and open files / folders and call the menu with the right button.
Now there are many different mice for the computer. There are wireless, small, large, with additional buttons for convenience, but its main function has remained the same after decades.
Acoustic system
As mentioned above, the speaker system is connected to the sound card. A signal is transmitted to the speakers through the audio, and you hear what they say in the video and sing in the song. Acoustics can be different, but without any, a computer with all its capabilities becomes an ordinary working tool, in front of which it is boring to spend time.
MFP - Multifunction devices
The MFP is more necessary for the office and study. Usually contains: scanner, printer, copier. Although this is all in one device, they perform completely different tasks:
- Scanner - makes an exact copy of a photograph / document in electronic form.
- Printer - prints an electronic version of the document, photos, pictures on paper.
- Xerox - Makes an exact copy from one paper to another.
Gamepad or joystick
The gamepad is also a joystick in the past. Needed only for comfort in some games. There are wireless and vice versa. Usually they contain no more than 15 buttons, and it makes no sense to use them in non-games.
Every more or less experienced user knows what is different types computers. In particular, they can be divided into stationary computers, nettops, all-in-ones, laptops, netbooks, tablet computers and even PDAs, although these are gradually disappearing from the market and giving way to tablets and smartphones. Let's define what types of computers exist and what are their main differences.
Personal Computer
This is a classic version of a modern PC, which consists of a system unit and a monitor. Mouse, keyboard, speakers are connected to the block itself. Conventionally, such systems are divided into office, home, gaming. Of course, such a division is very inaccurate, so you need to try to understand this in more detail.
office computers
Compile a document, edit a file, keep accounting records - approximately these types of work are performed by a computer in the office, therefore its components must be appropriate. For offices, the cheapest and weakest systems are selected, which are suitable only for working with office programs. However, if the company is engaged in drawing in programs like Autocad, then more powerful systems can be used in offices.
Homemade
When choosing a PC for the home, users try to choose the most advanced systems and powerful components, good monitors. Most do not want to buy processors with integrated video cards, but prefer discrete cards. home computer should be able to not only play movies and open documents, but even games. Such a system should also be equipped with a large monitor - spending time at such a computer at home is much more pleasant.
Gaming
These are the most powerful systems with a huge amount of RAM, a very powerful CPU and an expensive graphics card. Such instances may be water-cooled (rather than conventional air-cooled), since the components of such a system quickly heat up to high temperatures.
In some variants, several powerful video cards are used, which, thanks to Crossfire and SLI technologies, work together. Also, in such systems, new types of disks (SSD) are necessarily installed, which provide a higher speed of data access. Moreover, special types of screens are even used for them. Computers for the game are equipped with cool monitors with a wide diagonal and a minimum pixel response time. The most innovative to date is Samsung model CHG90 GLED with a 49-inch diagonal and a unique resolution of 3840x1080.
As for the amount of RAM, gaming systems can use 16 or even 32 GB of RAM, but this is not the limit. Also, in a gaming personal computer, the types of memory should be the most modern. Today it is DDR4.
And all this only applies personal computers. Different types of platforms can be used in this case. They can be based on AMD, Intel, Nvidia, Radeon components, and sometimes they can be combined with each other.
Nettops
This type of computer is distinguished by its compactness. Nettops are designed for work, ill-suited for home use and completely unsuitable for games. In general, the term "Nettop" was introduced by Intel when demonstrating its new processors. Intel Atom, which, as the representatives of the company believed, should become the basis and basis for creating nettops.
If we give an analogy, then this type of computer is a stationary analogue of a laptop or netbook. These computers have traditional monitors, a mouse and keyboard, but the system unit used is so small that it can be easily attached to back panel monitor. As a result, there is no huge box, which saves space.
Nettops are very weak computers, which are equipped with budget hardware. Due to the low performance of the components, they heat up very little, which makes it possible to place them in a small box without effective cooling. This box is carefully attached to the monitor. Due to the use of weak components, such systems are very cheap, so they are often bought for use in offices. They enable users to work with office programs, browsers, etc. It is definitely not worth expecting high performance from them. Their main task is to ensure the possibility of staff work and at the same time save the company's budget. They are doing great with her.
Good examples of the implementation of these types of computers are the following models: ASUS Eee Box, Acer AspireRevo AR1600. These systems are based on an Intel Atom chip and an Nvidia graphics card.
Note that although nettops are convenient solution for offices, they practically did not take root. Most often, even in small companies, cheap desktop computers with classic system blocks are purchased for the needs of staff.
Monoblocks
This type of computer is very similar to a nettop, only in this case in a single case there is a screen, components, speakers, a webcam, a microphone. Such a computer is ergonomic, takes up little space (at least there is no clumsy system unit), and looks aesthetically pleasing. It is also more portable than a conventional desktop PC.
However, there are also disadvantages of such a device. At a minimum, it is more difficult to repair and upgrade. And if something breaks inside, then it will be very difficult to replace and even more so repair the component. If the monoblock is not under warranty, then you will have to pay for the repair service yourself, and it will cost more than repairing a classic desktop computer.
Given the fact that such computers are most often bought for the home, they have recently begun to integrate TV tuners that allow you to watch TV. That is, such a device combines a computer and a TV, which is convenient. More advanced computers are equipped with touch displays, which generally eliminates the keyboard and mouse. Well-known candy bars from Apple are popular, however, they are extremely expensive. By the way, the price is the main disadvantage of such systems. At a high cost, they use weak components, which, if they provide high performance, only when performing template tasks. You can't play games on these computers.
tablet computers
Tablets are very popular today and are actively sold in the respective stores. Initially, it was thought that they would be used as a working tool, although in fact, users buy them as multimedia devices. Tablets are comfortable to sit in social networks, Internet, watch movies, read books. It may seem that a modern tablet is a reduced monoblock, but, in fact, it is not. In a monoblock, it is possible to implement air cooling by installing fans. There is no such possibility in the tablet, therefore, a priori, weak hardware is used here. And although modern mobile processors are powerful, they are still inferior in performance to full-fledged ones.
laptops
Most citizens have these portable personal computers. This is one of the most practical types of PC, which is very popular. There are many models on the market from different manufacturers.
A feature of the laptop is its portable case, which is divided into two parts: in one part there are components (it can be both powerful hardware and budget), in the other - the screen. Moreover, the type of computer screens can be any: with IPS, PVA, TN, MVA matrix, with large or narrow viewing angles, etc.
As for accessories, there is also room for choice. For work or study, you can pick up a weak laptop with budget hardware, and for games, some manufacturers create quite expensive gaming platforms with efficient cooling and powerful components.
The difference between a laptop and a monoblock or nettop is not only its physical design, but also offline work. Thanks to the use of the battery, the laptop can be used on the street, in a cafe, at the institute. Truth, modern models Without recharging, they can work for three to four hours, but this is already quite good. Some standalone laptops at a low brightness setting can last 15 hours.
By the way, laptops in the West (and in our country too) are called laptops (laptop). They have certain advantages over desktop computers in the form of classic systems, monoblocks and even nettops:
- Light weight.
- Compactness and possibility of transformation.
- Autonomy.
At the same time, laptops have the same capabilities as conventional stationary models. They are initially equipped with adapters for receiving wifi signal, webcam, keyboard (built into the case). The touchpad serves as a mouse, although a full-fledged mouse can be connected via the USB interface.
On the this moment many manufacturers produce laptops. Samsung, Acer, Asus, Lenovo products are very popular. These companies offer a fairly large selection of laptops in the middle price range. Manufacturers such as MSI are introducing high-end laptops. They specialize in the implementation of gaming platforms with efficient cooling systems and the best hardware. Naturally, a computer with productive components will be able to process any kind of information. And just because it was designed for games doesn't mean it can't work.
Netbooks
Once laptops became very popular, some manufacturers took a bold step towards reducing the already compact devices. As a result, netbooks appeared - smaller analogues of laptops that had 10-inch displays (most often the screen diagonal was just that). It is difficult to say what kinds of work a computer of this type performs. Most likely, they were intended for accessing the Internet, working with office applications, although their hardware was so weak that it was not possible to launch a couple of extra processes. Typically, netbooks used Intel Atom processors, which Intel previously made for nettops, they found their way into netbooks.
And although such models were compact and very light, they very quickly disappeared from the market due to low demand. Today it is difficult to find a netbook in a store, as it is unprofitable to sell them. Everyone prefers to use classic laptops, despite the fact that they are bigger and heavier.
Smartphones or PDAs
Previously, PDAs (personal pocket computers) were in units. However, this gadget did not catch on, as soon after its introduction, ordinary mobile phones were transformed into smartphones. They improved, became affordable, so the need for a PDA has completely disappeared. In their device, smartphones are very close to tablet computers and differ from them only in a smaller screen and the presence of slots for SIM cards, which allows you to make calls.
Finally
The personal computer and its types are constantly changing. It is possible that in the near future there will be some new type of PC that will revolutionize the field of digital technology. Sooner or later, this will definitely happen, because every year the components become more powerful and productive.
A personal computer is a universal technical system.
Its configuration (composition of equipment) can be flexibly changed as needed.
However, there is the concept of a basic configuration, which is considered typical. In such a kit, the computer is usually supplied.
The concept of a basic configuration may change.
Currently, four devices are considered in the basic configuration:
- system unit;
- monitor;
- keyboard
- mouse.
In addition to computers with a basic configuration, multimedia computers equipped with a CD drive, speakers and a microphone are becoming more common.
Reference: "Yulmart", by far the best and most convenient online store where for free you will be advised when buying a computer of any configuration.
The system unit is the main node inside which the most important components are installed.
Devices that are inside the system unit are called internal, and devices connected to it from the outside are called external.
External additional devices designed for input, output and long-term storage of data are also called peripheral.
How the system unit is arranged
By appearance system blocks differ in the shape of the case.
Personal computer cases are produced in horizontal (desktop) and vertical (tower) versions.
Cases having a vertical design are distinguished by dimensions:
- full-size (big tower);
- mid-sized (midi tower);
- small size (mini tower).
Among cases that have a horizontal design, there are flat and extra flat (slim).
The choice of one or another type of case is determined by the taste and needs of upgrading the computer.
The most optimal case type for most users is the mini tower case.
It has small dimensions, it is convenient to place it both on the desktop and on the bedside table near the desktop or on a special holder.
It has enough space to accommodate five to seven expansion boards.
In addition to the form, a parameter called the form factor is important for the case. The requirements for placed devices depend on it.
Currently, two form factors are mainly used: AT and ATX.
The form factor of the case must necessarily be consistent with the form factor of the main (system) board of the computer, the so-called motherboard.
Personal computer cases are supplied with a power supply, and thus the power of the power supply is also one of the parameters of the case.
For mass models, the power supply of 200-250 W is sufficient.
The system unit includes (fits):
- Motherboard
- ROM chip and BIOS
- Non-volatile CMOS memory
- HDD
Motherboard
Motherboard (mother board) - the main board of a personal computer, which is a sheet of fiberglass covered with copper foil.
By etching the foil, thin copper conductors are obtained that connect electronic components.
The motherboard contains:
- processor - the main microcircuit that performs most of the mathematical and logical operations;
- tires - sets of conductors through which signals are exchanged between the internal devices of a computer;
- random access memory (random access memory, RAM) - a set of chips designed for temporary storage of data when the computer is turned on;
- ROM (read-only memory) - a microcircuit designed for long-term storage of data, including when the computer is turned off;
- microprocessor set (chipset) - a set of microcircuits that control the operation of the internal devices of a computer and determine the main functionality motherboard;
- connectors for connecting additional devices (slots).
(microprocessor, CPU, CPU) - the main microcircuit of the computer, in which all calculations are performed.
It is a large chip that can be easily found on the motherboard.
The processor has a large copper finned heatsink cooled by a fan.
Structurally, the processor consists of cells in which data can not only be stored, but also changed.
The internal cells of the processor are called registers.
It is also important to note that data in some registers is considered not as data, but as commands that control the processing of data in other registers.
Among the processor registers there are those that, depending on their content, are able to modify the execution of commands. Thus, by controlling the sending of data to different registers of the processor, it is possible to control the processing of data.
This is what programs are based on.
With the rest of the computer devices, and primarily with RAM, the processor is connected by several groups of conductors called buses.
There are three main buses: data bus, address bus and command bus.
address bus
Intel Pentium processors (namely, they are most common in personal computers) have a 32-bit address bus, that is, it consists of 32 parallel lines. Depending on whether there is voltage on one of the lines or not, they say that one or zero is set on this line. The combination of 32 zeros and ones forms a 32-bit address pointing to one of the RAM cells. The processor is connected to it to copy data from the cell to one of its registers.
Data bus
This bus is used to copy data from RAM to processor registers and vice versa. In computers assembled on the basis of Intel Pentium processors, the data bus is 64-bit, that is, it consists of 64 lines, along which 8 bytes are sent for processing at once.
Command bus
In order for the processor to process data, it needs instructions. It must know what to do with those bytes that are stored in its registers. These commands come to the processor also from RAM, but not from those areas where data arrays are stored, but from where programs are stored. Commands are also represented as bytes. The simplest commands fit into one byte, but there are also those that require two, three or more bytes. Most modern processors command bus 32-bit (for example, in Intel processor Pentium), although there are 64-bit processors and even 128-bit ones.
During operation, the processor serves the data in its registers, in the RAM field, as well as the data in the external ports of the processor.
It interprets part of the data directly as data, part of the data as address data, and part as commands.
The set of all possible instructions that the processor can execute on data forms the so-called processor instruction set.
The main parameters of the processors are:
- operating voltage
- bit depth
- operating clock frequency
- internal clock multiplier
- cache size
The operating voltage of the processor is provided by the motherboard, so different brands processors correspond to different motherboards (they must be selected together). With the development of processor technology, a gradual decrease in the operating voltage occurs.
The processor capacity indicates how many bits of data it can receive and process in its registers at a time (per clock cycle).
The processor is based on the same clock principle as in conventional clocks. The execution of each command takes a certain number of cycles.
AT wall clock the oscillation cycles are set by the pendulum; in manual mechanical watch they are set by a spring pendulum; in an electronic clock, for this there is an oscillatory circuit that sets the cycles of a strictly defined frequency.
In a personal computer, clock pulses are set by one of the microcircuits included in the microprocessor kit (chipset) located on the motherboard.
The higher the frequency of clocks received by the processor, the more commands it can execute per unit of time, the higher its performance.
The exchange of data within the processor is several times faster than the exchange with other devices, such as RAM.
In order to reduce the number of accesses to RAM, a buffer area is created inside the processor - the so-called cache memory. This is, as it were, "super-RAM".
When the processor needs data, it first goes to the cache memory, and only if the necessary data is not there, it goes to RAM.
Receiving a block of data from RAM, the processor enters it at the same time into the cache memory.
"Successful" cache accesses are called cache hits.
The percentage of hits is higher, the larger the cache memory, so high-performance processors are equipped with an increased amount of cache memory.
Often cache memory is distributed over several levels.
The cache of the first level is executed in the same chip as the processor itself, and has a size of the order of tens of kilobytes.
The L2 cache resides either on the processor die or on the same node as the processor, although it runs on a separate die.
The cache memory of the first and second levels operates at a frequency consistent with the frequency of the processor core.
The third-level cache is made on high-speed chips such as SRAM and is placed on the motherboard near the processor. Its volumes can reach several MB, but it works at the frequency of the motherboard.
Bus interfaces of the motherboard
Communication between all own and connected devices of the motherboard is carried out by its buses and logical devices located in microprocessor chips (chipset).
The performance of the computer largely depends on the architecture of these elements.
Bus interfaces
ISA(Industry Standard Architecture) is an obsolete system bus for IBM PC-compatible computers.
EISA(Extended Industry Standard Architecture) - An extension of the ISA standard. Features a larger connector and increased performance (up to 32 MB/s). Like ISA, currently this standard considered obsolete.
PCI(Peripheral Component Interconnect - literally: the relationship of peripheral components) - an input / output bus for connecting peripheral devices to the computer motherboard.
AGP(Accelerated Graphics Port - accelerated graphics port) - developed in 1997 by Intel, a specialized 32-bit system bus for a video card. The main task of the developers was to increase the performance and reduce the cost of the video card by reducing the amount of built-in video memory.
USB(Universal Serial Bus - universal serial bus) - This standard defines the way the computer interacts with peripheral equipment. It allows you to connect up to 256 various devices having a serial interface. Devices can be switched on in chains (each next device is connected to the previous one). The performance of the USB bus is relatively low and is up to 1.5 Mbps, but for devices such as a keyboard, mouse, modem, joystick, and the like, this is enough. The convenience of the bus lies in the fact that it virtually eliminates conflicts between different equipment, allows you to connect and disconnect devices in "hot mode" (without turning off the computer), and allows you to combine several computers into the simplest local network without the use of special equipment and software.
The parameters of the microprocessor kit (chipset) determine the properties and functions of the motherboard to the greatest extent.
Currently, most motherboard chipsets are based on two chips, called the "north bridge" and "south bridge".
The "Northbridge" controls the interconnection of four devices: processor, RAM, AGP port and PCI bus. Therefore, it is also called a four-port controller.
The "south bridge" is also called the functional controller. It performs the functions of a controller for hard and floppy disks, the functions of an ISA-PCI bridge, a keyboard controller, a mouse, a USB bus, and the like.
(RAM - Random Access Memory) is an array of crystalline cells capable of storing data.
There are many different types of RAM, but in terms of the physical principle of operation, a distinction is made between dynamic memory (DRAM) and static memory (SRAM).
Dynamic memory cells (DRAM) can be represented as microcapacitors capable of accumulating charge on their plates.
This is the most common and economically available type of memory.
The disadvantages of this type are connected, firstly, with the fact that both when charging and discharging capacitors, transient processes are inevitable, that is, data recording is relatively slow.
Second important disadvantage due to the fact that the charges of the cells tend to dissipate in space, and very quickly.
If the RAM is not constantly “recharged”, data loss occurs after a few hundredths of a second.
To combat this phenomenon, the computer is constantly regenerating (refreshing, recharging) RAM cells.
Regeneration is carried out several tens of times per second and causes waste of computing system resources.
Static memory cells (SRAM) can be thought of as electronic microelements - triggers, consisting of several transistors.
The trigger does not store the charge, but the state (on / off), so this type of memory provides more high performance, although technologically it is more complicated and, accordingly, more expensive.
Dynamic memory chips are used as the main RAM of a computer.
Static memory chips are used as an auxiliary memory (the so-called cache memory) designed to optimize the performance of the processor.
Each memory cell has its own address, which is expressed as a number.
One addressable cell contains eight binary cells in which 8 bits can be stored, i.e. one byte of data.
Thus, the address of any memory cell can be expressed in four bytes.
RAM in a computer is located on standard sockets called modules.
RAM modules are inserted into the appropriate slots on the motherboard.
Structurally, memory modules have two versions - single-row (SIMM-modules) and double-row (DIMM-modules).
The main characteristics of RAM modules are the amount of memory and the access time.
Access time indicates how long it takes to access memory locations - the smaller it is, the better. Access time is measured in billionths of a second (nanoseconds, ns).
ROM chip and BIOS
At the moment the computer is turned on, there is nothing in its RAM - no data, no programs, since RAM cannot store anything without recharging cells for more than hundredths of a second, but the processor needs commands, including at the first moment after turning on.
Therefore, immediately after switching on, the starting address is set on the address bus of the processor.
This happens in hardware, without the participation of programs (always the same).
The processor turns to the exposed address for its first command and then starts working on programs.
This source address cannot point to RAM, which has nothing in it yet.
It points to another type of memory - Read Only Memory (ROM).
The ROM chip is capable of storing information for a long time, even when the computer is turned off.
Programs in ROM are called "hardwired" - they are written there at the stage of manufacturing the microcircuit.
A set of programs located in ROM forms a basic input-output system (BIOS - Basic Input Output System).
The main purpose of the programs in this package is to check the composition and performance of computer system and provide interaction with the keyboard, monitor, hard drive and a floppy disk drive.
The programs included in the BIOS allow us to observe diagnostic messages on the screen that accompany the computer startup, as well as interfere with the startup process using the keyboard.
Non-volatile CMOS memory
The work of such standard devices as a keyboard can be serviced by programs included in the BIOS, but such means cannot ensure work with all possible devices.
So, for example, BIOS manufacturers know absolutely nothing about the parameters of our hard and floppy disks, they do not know either the composition or properties of an arbitrary computer system.
In order to get started with other hardware, the programs included with the BIOS must know where to find the settings you need.
For obvious reasons, they cannot be stored in either RAM or ROM.
Especially for this, the motherboard has a “non-volatile memory” microcircuit, which is called CMOS according to manufacturing technology.
It differs from RAM in that its contents are not erased when the computer is turned off, and it differs from ROM in that data can be entered and changed in it independently, in accordance with what equipment is included in the system.
This chip is constantly powered by a small battery located on the motherboard.
The charge of this battery is enough to ensure that the microcircuit does not lose data, even if the computer is not turned on for several years.
The CMOS chip stores flex and hard drives, about the processor, about some other devices on the motherboard.
The fact that the computer clearly keeps track of the time and calendar (even when turned off) is also due to the fact that the system clock is constantly stored (and changed) in CMOS.
Thus, the programs written in the BIOS read data on the composition of the computer hardware from the CMOS chip, after which they can access the hard disk, and, if necessary, the flexible one, and transfer control to those programs that are written there.
HDD
HDD- the main device for long-term storage of large amounts of data and programs.
In fact, this is not one disk, but a group of coaxial disks that have a magnetic coating and rotate at high speed.
Thus, this "disk" does not have two surfaces, as an ordinary flat disk should have, but 2n surfaces, where n is the number individual disks in a group.
Above each surface is a head for reading and writing data.
At high disk rotation speeds (90 rpm), an aerodynamic cushion is formed in the gap between the head and the surface, and the head hovers above the magnetic surface at a height of several thousandths of a millimeter.
When changing the strength of the current flowing through the head, there is a change in the intensity of the dynamic magnetic field in the gap, which causes changes in the stationary magnetic field of ferromagnetic particles that form the coating of the disk. This is how data is written to the magnetic disk.
The read operation occurs in reverse order.
Magnetized coating particles moving at high speed near the head induce self-induction EMF in it.
The electromagnetic signals that arise in this case are amplified and transmitted for processing.
Work management hard drive performs a special hardware-logical device - the hard disk controller.
Currently, the functions of disk controllers are performed by microcircuits included in the microprocessor kit (chipset), although some types of high-performance controllers hard drives are still supplied on a separate board.
The main parameters of hard drives are capacity and performance.
It can be stored on a hard drive for years, but sometimes it needs to be transferred from one computer to another.
Despite its name, a hard drive is a very fragile device that is sensitive to overloads, shocks and shocks.
Theoretically, it is possible to transfer information from one workplace to another by transferring a hard drive, and in some cases they do, but still this technique is considered low-tech, since it requires special care and certain qualifications.
For the rapid transfer of small amounts of information, so-called floppy magnetic disks (floppy disks) are used, which are inserted into a special drive - a disk drive.
The drive inlet is located on the front panel of the system unit.
Starting in 1984, high-density 5.25-inch (1.2 MB) floppy disks were produced.
Today, 5.25-inch drives are not used, and the corresponding drives are not supplied in the basic configuration of personal computers after 1994.
3.5" floppy disks have been produced since 1980.
High-density 3.5-inch drives are now considered standard. They have a capacity of 1440 KB (1.4 MB) and are marked with the letters HD (high density - high density).
On the underside, the floppy disk has a central sleeve, which is captured by the disk drive spindle and rotated.
The magnetic surface is covered with a sliding shutter to protect it from moisture, dirt and dust.
If valuable data is recorded on a floppy disk, it can be protected from being erased and overwritten by sliding the protective slide so that an open hole is formed.
Floppy disks are considered unreliable storage media.
Dust, dirt, moisture, temperature fluctuations and external electromagnetic fields very often cause partial or complete loss of data stored on a floppy disk.
Therefore, using floppy disks as the main means of storing information is unacceptable.
They are used only for transporting information or as an additional (backup) storage medium.
CD-ROM drive
The abbreviation CD-ROM (Compact Disc Read-Only Memory) is translated into Russian as a read-only memory device based on a compact disc.
The principle of operation of this device is to read numerical data using a laser beam reflected from the surface of the disk.
Digital recording on a CD differs from recording on magnetic discs in a very high density, and a standard CD can store approximately 650 MB of data.
Large amounts of data are typical for multimedia information (graphics, music, video), so CD-ROM drives are classified as multimedia hardware.
Software products distributed on laser discs are called multimedia publications.
Today, multimedia publications are gaining a stronger place among other traditional types of publications.
So, for example, there are books, albums, encyclopedias and even periodicals ( electronic journals) released on CD-ROM.
The main disadvantage of standard CD-ROM drives is the impossibility of writing data, but in parallel with them, there are also one-time devices. CD-R recordings(Compact Disk Recorder), and CD-RW recorders.
The main parameter of CD-ROM drives is the data reading speed.
Currently, CD-ROM readers with a performance of 32x-50x are most widely used. Modern samples of write-once devices have a capacity of 4x-8x, and multiple-write devices - up to 4x.
Good day to you and thank you very much for your interest in our materials. Today we will talk about what a computer consists of. You probably know most of what will be discussed in this lesson, however, if you missed something, then when studying further lessons, you may simply not understand everything.
First, let's talk a little about the terminology that is used by users and specialists. We have created a separate section called . Quite often, when people hear a conversation between two computer specialists, their reaction is most often this: "They are talking in an unfamiliar language, nothing is clear!" - so there is a certain kind of language barrier between specialists, advanced users and beginner users. When I first entered a technical school for a computer specialty, I myself was initially struck by the vocabulary of my classmates, who already had computers at that time and even shocked me a little and began to evoke such thoughts in my head: "And how are they in this do they understand everything?”, “How can I manage to master all this?”, “I don’t understand anything, am I the only one here such a fool?” - therefore, this feeling is familiar to me, and not only familiar, but also tried on my own experience. So, to overcome this "language barrier" a small glossary has been created. It is still quite small, but from lesson to lesson we will expand it with new words. In general, speaking to the point, a normal specialist will never shower a beginner with a bunch of slang and special terms, so as not to confuse a person, but if you come across such a "specialist", then you should know that he is most likely also a teapot, he just learned a few smart words, or just does not want to make contact. At the beginning and at the end of the lesson, I will provide a dictionary with new words, but you can always refer to the link "Dictionary of the most popular computer technical terms and professional slang". I will also include the names of the system and peripheral equipment of a personal computer.
Main computer components
System unit
The system unit is the computer itself. Some incorrectly call the system unit "processor", however, this is a gross mistake, because. The processor is the heart of the computer, which is located inside the system unit. We will talk about what is inside the system unit in the next lessons - there are a lot of interesting things besides the processor.
Monitor
Monitor (display) - used to display information from a computer. They are divided into CRT (based on a cathode ray tube) and LCD (liquid crystal). The first type continues to slowly but surely leave our homes and workplaces, but there are still workplaces that have high-quality "tube" monitors with a large screen diagonal. Usually these are the workplaces of designers who care about high quality color reproduction.
Keyboard
The keyboard (clave, keyboard, keyboard) is the most basic and, by the nature of the service, the most enduring computer device, the main purpose of which is to enter information into the computer, and the secondary purpose is to resist crawling cockroaches, spilled coffee, compote, tea and other drinks and food that like to eat and drink people sitting at the computer. Moreover, in accordance with the law of meanness, the more expensive the keyboard, the worse it resists "non-primary" factors.
Manipulator "Computer mouse"
Mouse (mouse, tailed, mouse) - a manipulator that makes it easier for the user to work in the graphical environment of the operating room Windows systems, regardless of version. This small peripheral is significantly more common than others:
- falls to the floor
- remains without a tail;
- most often fails.
In relation to the mouse, terms such as "click" or "click" (from the English click - click) are used - these words indicate pressing the right or left mouse button. "Double click" or "Double click" means two clicks on the mouse button with a minimum time interval between clicks, i.e. if you are told that you need to "Double click" or "Double click" with the left mouse button, then this means that you need to double-click the left mouse button with a minimum time interval.
Printer
A printer is a device that allows you to print text, pictures, photographs on paper, and on copies equipped with specialized trays, it is possible to print on disks and plastic cards. They are divided into four types:
- matrix - this is such a disgustingly squealing unit that prints slowly, in one color and noisily. Such printers are used mainly in METRO supermarkets, well, and in some other places. This printer differs in truth by the penny cost of consumables. The principle of operation is very similar to a typewriter - the small needles of the print head hit the ink ribbon and, thus, the image is transferred to the paper. These printers are only suitable for printing text on paper.
- inkjet (pictured) - these printers use liquid ink, which is applied to paper through the nozzles of piezoelectric heads. They differ in the number of colors in the cartridges, the number of cartridges used at the same time, the speed and quality of printing. Suitable for printing on paper and on a specialized film of text, pictures, photographs, as well as disks and plastic cards (depending on the printer model). They are distinguished by the low cost of the printers themselves and the high cost of consumables.
- laser - the image is applied to the paper by transferring the toner from the photodrum shaft and cauterized by the stove. A distinctive feature of these printers is the high speed and quality of printing, the high cost of the printers themselves, which is compensated for large print volumes by the ratio of the cost of consumables to the number of printed sheets at 5% coverage. Suitable for printing on paper and specialized film.
- thermal printer - these printers surround us everywhere, from cash registers to fax machines and label printers. In this model of printers, either thermal transfer of ink from an ink ribbon (thermal transfer printer) is used, or paper with a special coating is used, which darkens when heated.
Scanner
Scanner (how to choose a scanner - soon on our website) - a device that allows you to transfer information from paper or film to the computer's memory in electronic form. Scanners are divided into five types:
- manual (aka "rake") - you hold this scanner in your hands and run it over the surface of the scanned page of text. Very impractical devices - are used only where they are really indispensable.
- flatbed (pictured) - the most common scanner for home and office. There is a glass slide on which the original is placed, there is a cover with which this original is closed and thus pressed against the glass for better scanning. There are instances with the so-called slide modules - they allow you to scan photographic films or slides.
- slide scanner - from the name it is already clear that this scanner is used exclusively for scanning films and slides. At the same time, the scanning quality of a slide scanner is certainly higher than that of a flatbed with a slide module.
- industrial - these scanners, as the name implies, are used only for professional purposes, they are very expensive and no one definitely needs them at home. They can usually scan originals that are larger than regular A1 size student papers.
- Barcode Scanner- we encounter this kind of scanner every time we get into a self-service store. Specialized scanners designed exclusively for barcode recognition.
Of course, these are far from all devices that can be connected to a computer, because there are also external drives information, devices that can be controlled using a computer, etc., but we will talk about this in the next lessons so as not to overload you with information.
In the next lesson, we will look at the basic principles of working in the operating system. Microsoft Windows. Due to the fact that you are reading this information from a computer screen, I can assume that you yourself know most of these tricks, however, you might have missed something or simply no one told you all the points - I recommend reading, because. to. We will also talk about ways to make work easier.
The main devices of the computer "live" in the system unit. These include: motherboard, processor, video card, RAM, hard drive. But outside of it, usually on the table, no less important computer devices also “live”. Such as: monitor, mouse, keyboard, speakers, printer.
In this article, we will look at What does computer consist of what these devices look like, what function they perform and where they are located.
System unit.
In the first category, we will analyze those devices, or they are also called components that “hide” in the system unit. They are the most important for his work. By the way, you can immediately look into the system unit. It's not hard. It is enough to unscrew the two bolts at the back of the system unit and move the cover to the side, and then we will see a view of the most important computer devices, in order, which we will now consider.
The motherboard is printed circuit board, which is designed to connect the main components of the computer. Some of them, for example, a processor or a video card, are installed directly on the motherboard itself in a slot designed for this. And the other part of the components, for example, a hard drive or a power supply, is connected to the motherboard using special cables.
The processor is a microchip and at the same time the "brain" of the computer. Why? Because he is responsible for the execution of all operations. How better processor the faster it will perform these very operations, respectively, the computer will work faster. The processor of course affects the speed of the computer, and even very strongly, but the speed of the PC will also depend on your hard drive, video card and RAM. So the most powerful processor does not guarantee a high speed of the computer if the other components have long been outdated.
3. Video card.
A video card, or otherwise a graphics card, is designed to display images on a monitor screen. It is also installed in the motherboard, in a special connector PSI-Express. Less commonly, a video card can be built into the motherboard itself, but its power is most often enough only for office applications and browsing the Internet.
RAM is such a rectangular bar, similar to a cartridge from old game consoles. It is intended for temporary data storage. For example, it stores the clipboard. We copied some text on the site, and immediately it got into the RAM. Information about running programs, computer sleep mode and other temporary data is stored in RAM. A feature of the RAM is that the data from it is completely deleted after the computer is turned off.
A hard drive, unlike RAM, is designed for long-term storage of files. In another way it is called Winchester. It stores data on special plates. Also recently there has been a proliferation SSD drive and.
Their features include high speed, but there is immediately a minus - they are expensive. A 64 GB SSD drive will cost you the same price as a 750 GB hard drive. Imagine how much an SSD for several hundred gigabytes will cost. Wo, woo! But do not be upset, you can buy a 64 GB SSD drive and use it in the form system disk, that is, install Windows on it. They say that the speed of work increases several times. The system starts very quickly, programs fly. I'm planning to switch to an SSD and keep my regular files on a traditional hard drive.
A disk drive is needed to work with disks. Although it is already much less often used, nevertheless, on stationary computers he hasn't interfered yet. At a minimum, a drive will come in handy for installing the system.
6. Cooling systems.
The cooling system is the fans that cool the components. Usually three or more coolers are installed. Be sure to have one on the processor, one on the video card, and one on the power supply, and then on request. If something is warm, then it is desirable to cool. Fans are also installed on hard drives and in the case itself. If the cooler in the case is installed on the front panel, then it takes heat, and the coolers installed on the rear compartment supply cold air to the system.
The sound card outputs sound to the speakers. It is usually built into the motherboard. But it happens that it either breaks down, and therefore is bought separately, or initially the quality of the standard PC owner is not satisfied and he buys another sound system. In general, the sound card also has the right to be in this list of PC devices.
The power supply is needed in order for all the above computer devices to work. It provides all components with the necessary amount of electricity.
8. Housing
And in order to put the motherboard, processor, video card, RAM, hard drive, floppy drive, sound card, power supply and possibly some additional components somewhere, we need a case. There, everything is neatly installed, twisted, connected and begins daily life, from switching on to switching off. The required temperature is maintained in the case, and everything is protected from damage.
As a result, we get a full-fledged system unit, with all essential devices computer required for its operation.
Peripherals.
Well, in order to fully start working on a computer, and not look at the “buzzing” system unit, we need Peripherals. These include those computer components that are outside the system unit.
The monitor itself is needed to see what we are working with. The video card sends the image to the monitor. They are connected to each other with a VGA or HDMI cable.
The keyboard is designed to enter information, well, of course, what kind of work without a full-fledged keyboard. Type text, play games, surf the Internet, and everywhere you need a keyboard.
3. Mouse.
The mouse is needed to control the cursor on the screen. Move it in different directions, click, open files and folders, call various functions and much more. Just like without a keyboard, without a mouse, nowhere.
4. Speakers.
Speakers are needed mainly for listening to music, watching movies and playing games. Who else uses speakers today more than they are played daily ordinary users in these tasks.
A printer and a scanner are needed to print and scan documents and everything that is needed in the field of printing. Or MFP, multifunctional device. It will come in handy for all those who often print, scan, make photocopies and do many other tasks with this device.
In this article, we only briefly reviewed the main computer devices, and in others, the links to which you see below, we will consider in detail all the most popular peripherals, as well as components that are part of the system unit, that is, components.
Enjoy reading!