Ours to you with a brush, dear and not very dear comrades! :)

As you know, there is a project on the site Notes of the System Administrator, which is updated as much as possible, which is not always the case.

Today our hands are free and we, with great pleasure, will once again look under the hood of our iron horse and deal with the motherboard, as well as all its personal belongings. The first part of the article, if you remember, was already "" and today we just have its continuation.

Actually, we think that you all have already clung to the blue screens of monitors (or whatever you have there), and therefore we begin.

Motherboard: what, why and why?

I would like to start the narrative with one philistine conversation between two "systemists". So, somehow two peppers meet and one says to the other: “My mother died yesterday, I took out the brains, replaced them and everything began to fly.” It may seem to a casual listener that people are talking some kind of nonsense and call the police, how can you say such a thing? However, after thinking, you still understand that two admins met and they are talking about the motherboard, which is called “mother” in the common people. Actually, the latter, as you already understood, is the subject of this article.

Motherboard (motherboard / system board), - the alpha and omega of any personal computer. It is on it that all the vital components necessary for “breathing” life into your computer are located. The motherboard is a skeleton to which everything else is attached, and therefore, if it is initially shaky, then the output is a “so-so person” (weak computer). Therefore, if you want to have a competitive car for a long time, it is very important to be able to choose correctly and understand all the insides motherboard. This is what we have to do next.

I think you are aware that a PC is a complex of many components, each with its own roles and functions. So, the mission of the motherboard is to establish interaction (dialogue) between a huge number of different computer modules. It is on its characteristics that the survivability of your iron horse depends, i.e. how long he can adequately (without lags and brakes) pull his strap.

The features of the motherboard (MP) include the fact that it:

• Allows very strong variation of different components (principle of complementation and interchangeability);
• Supports one type of processor and several types of memory;
• To work correctly and together MP, cases and power supplies, they must be compatible.

You also need to know that there are, conditionally, two types of motherboards (although, as a rule, combos of these two have been made for a long time):

• Integrated(integrated motherboard), - most of its components are soldered on board, unlike expansion cards, which are removable. The main advantage of such boards is their portability and cheaper production. The disadvantage is that if one component grunts, you will have to change the entire board (hello laptops / netbooks).
• Non-integrated(non-integrated motherboard), - has expansion slots with some non-removable components (video card, disk controllers). The main plus is the flexibility in relation to the replacement of faulty components. When an expansion board fails, it can be easily replaced.

Note:
For a more powerful assimilation of the material, all further narration will be divided into subchapters.

Motherboard Form Factors
When choosing a motherboard, you need to remember such a parameter as the form factor. This characteristic is responsible for the ability to push the mother into the body of her iron horse. That is, - attention!, - not every motherboard can be installed in your system unit. In order to avoid dancing with a file around the body and MP, it is necessary to understand its anthropometry (sizes). Let's look at this in more detail.

Form factor - the linear dimensions and position of the device components laid down by the manufacturer (during the design process). At the moment, there is the following classification of the main (most popular) form factors.

You don't have to know the specific linear dimensions - just remember when buying that each motherboard has its own form factor and can only be plugged into a certain type of PC case.

The motherboard is made up of Motherboard components.
The main base, foundation, substrate of the MP is a multilayer textolite, on which various capacitors, transistors, data exchange paths and other electrical elements are located. The tracks are located on the textolite layers, and special holes are made in the latter for their communication. Modern motherboards can contain up to 10-15 layers.

Here is what a textolite for the manufacture of motherboards clearly represents:

Despite the similarity of the production process, each manufacturer tries to stand out and release its own unique product. The main players in the “mom market” (an interesting phrase turned out :)) are: ASUS, Gigabyte, MSI, Intel, Biostar.

Now let's move closer to the body and look at the insides of the motherboard.

So, each of you, having opened the cover of your computer case, can make sure that there is a board inside, securely fixed with small screws, through pre-drilled holes. Taking a quick look at the board, we will come to the conclusion that it contains:

• Ports for connecting all internal components (a single socket for the processor and several slots for RAM);
• Ports for attaching floppy/hard drives and optical drives using ribbon cables;
• Fans and dedicated power ports;
• Expansion slots for connecting peripheral cards (video/sound and other cards);
• Ports for connecting I / O devices: monitor, printer, mouse, keyboard, speakers and network cables;
• USB 2.0/3.0 slots.

If we omit some details, then the general scheme of any motherboard can be described as follows.

I am sure that many of you have not the latest motherboards under the hood, and therefore it would be most expedient to consider their insides, because then questions like: “But I don’t have this” and others like them will be an order of magnitude smaller.

Actually, let's, for example, take the Asus p8h67-V motherboard and describe all its visible components (see image, clickable).

It was a superficial look at the motherboard, half an eye, so to speak. Now (for especially curious and inquisitive minds) we will analyze all the insides thoroughly. Also, for example, let's take the board (though already older) ASUS P5AD2-E (2006 release) in order to know not only what we have now, but also from what we came to this.

This is what the mother looks like:

Agree, it’s quite nice when you yourself understand all your hardware and can tell your mini-story about every moment. This is not only a huge plus in the direction of the thriftiness of the PC owner, but also a guarantee that you can explain in adequate language at the service center what happened to the motherboard if it fails.

Actually, now let's go through each component separately, savoring all its details (the listing goes clockwise from the top corner).

No. 1. Expansion slots
Expansion slots are buses on the motherboard designed to connect additional boards to it. Examples are:

• PCI, - 32-bit (133 Mbit) bus (also available in 64-bit version), used in PCs of the late 90s and early 2000s. It complies with the PnP (plug and play) standard and does not require additional jumpers and microswitches. The boards are often described as PCI4, PCI5 and PCI6.
• AGP, - Accelerated Graphics Port, is a dedicated point-to-point channel that allows the graphics controller to directly access system memory. The AGP channel is 32-bit and operates at 66 MHz. The total throughput is 266 Mbit, which is significantly more than the PCI bandwidth;
• PCI Express is a serial bus that replaced PCI and AGP. Available in various formats: x1, x2, x4, x8, x12, x16 and x32. Data transmitted by PCI-Express is sent over wires called lanes in full duplex mode (in both directions at the same time). Each lane has a capacity of about 250 MBps and specifications can scale from 1 to 32 lanes.

All these slots look like this.

No. 2. 3-pin fan power connector
Case (system) fan - helps to bring air inside, as well as take hot air out of the case. Case fan (fan) most often has dimensions of 80 mm, 92 mm, 120 mm and a width of 25 mm.

Number 3. Rear connector block (back pane connectors)
Connection (connect) is a m / y connection with a plug and a socket. All peripheral devices (for example, mouse, keyboard, monitor) are connected to the computer in this way. This is what a standard back wall with a PC case connector block looks like.

No. 4. Radiator (heatsink)
A heat sink, a heat dissipator, is designed to keep a hot component (such as a CPU) cool. There are two types of radiators: active and passive. The active ones use the power of the air and these are the usual cooling devices in the form of a ball-bearing fan and the radiator itself. Passive radiators, on the other hand, have no mechanical components at all and dissipate heat through convection. This is how they look different types radiators (more correctly, we are talking about cooling systems).

No. 5. 4-pin (P4) power connector
P4 cable connector - 12V the power cable has 2 black wires (ground) and two yellow +12 VDC.

No. 6. Inductor
An electromagnetic coil is copper in a cylindrical shape around an iron core to store magnetic energy (choke). Used to remove voltage spikes and power dips.

No. 7. Capacitor
This component consists of 2 (or a set of 2) conductive plates with a thin insulator and wrapped in a plastic/ceramic container. When the capacitor gets D.C.(DC), a positive charge accumulates on one of the plates (or a set of plates) and a negative charge accumulates on the other. This charge remains in the capacitor until it is discharged.

The electrolytic capacitor, larger in capacity but in a smaller package, is the other most common type of capacitor. Like any PC component, it can fail (the expression capacitor is flashed) and the computer will no longer be bootable. In this case, it must be replaced, although only a few can do this with their own handles. Therefore, it is better to trust the electronic hands of the master.

No. 8. CPU socket
Socket - a socket for connecting the processor to the motherboard. It contains a certain number of legs, which allows you to install only a “stone” of a certain format into the motherboard (the number of legs corresponds to the number of socket holes). I must say that as the PC evolved, sockets changed quite often. Here are just a small part of them:

No. 9. Northbridge (north bridge)
Bridges - this specific term refers to a set of chips that are responsible for the operation of all components of the board, including their effective connection with the processor. North + south bridges form a chipset. These are two separate units that are responsible for many functions, such as managing the operation of the cache memory, the system bus, and loading many peripheral components / devices. Without bridges, a personal computer would be a mere pile of iron, unable to perform any action. Northbridge provides the operation of faster devices, and its counterpart, the southbridge, less high-speed ones.

For a better understanding, here is a diagram of the placement of both bridges relative to the components of the motherboard.

Bridges got their name because of their geographical location on the motherboard. The north one lies under the processor at the top of the board and, as a rule, uses additional cooling. South, respectively, below (to the south of the PCI bus) and does without cooling. The Northbridge is larger than its sibling and is the closest to CPU and memory. The Northbridge CPU can communicate via the following interfaces: FSB, DMI, HyperTransport, QPI.

It is worth saying that manufacturers are constantly looking for new ways to improve performance and reduce overall cost, and, as an option, they eventually began to transfer the memory controller from the north bridge to the processor die. In modern processors (in particular Core i7), the graphics controller is also sewn into the stone itself. Such technologies made it possible to abandon the use of the north bridge in principle, and it will gradually sink into oblivion, remaining only in our memories :).

No. 10. Screw holes
Metal (rarely plastic) screws that secure the motherboard to the case. In the process of installing the board in the case, it is installed in place (holes on the board to the holes in the case) and screwed on. Each motherboard has multiple holes that hold it securely in place.

No. 11. Memory slots
RAM slots are used to connect RAM, i.e. modules that store the operations performed by the computer. On average, the number of memory slots can reach from 2 to (sometimes more in high-end motherboards). In addition to the number of slots, there are types of memory. The most common type of desktop memory currently available is DDR 2, 3, and 4.

When buying a new computer or motherboard, you need to pay close attention to the types of memory it supports. Otherwise, even a file will not help you stick the memory into the “wrong” type of connectors (although a hammer and tape can help). The available number of motherboard memory slots indicates the possibility of increasing the operational potential of the PC. Therefore, the more slots and the fresher the standard they support, the longer the power of your iron horse will last.

They look different, in our case like this:

No. 12. Super I/O (SIO)
The integrated circuit on the motherboard that is responsible for handling the slower and less visible I/O devices. PCs are still used today to support older legacy devices.

Devices processed by the scheme include:

• Floppy disk controllers;
• Game / infrared ports;
• Keyboard and mouse (not USB);
• Parallel/serial ports;
• Real time clock;
• Temperature and fan speed sensor.

You can find it on the motherboard by the name of the manufacturer, in particular: Fintek, ITE, National Semiconductor, Nuvoton, SMSC, VIA, and Winbond.

No. 13. Connector for connecting floppy disks
A rather rare, but still (just some kind of miracle) component of the motherboard found in our time. A flexible flat cable that allows you to hook one or more floppy disks. The floppy disk drive is identified on the computer as drive A. The standard floppy connector contains 34 pins.

No. 14. ATA (IDE) connector
Already outdated standard interface for connecting hard drives to the motherboard. It happens primary / secondary and allows using a jumper to set the master and slave hard drives. It has long been replaced by a SATA connector.

No. 15. 24-pin ATX power connector
The largest of the connectors that powers the motherboard (connects it to the power supply). Previously, such a cable had 20 holes, now, as a rule, 24. A 24-pin power supply can be used on a 20-pin motherboard, leaving the four extra pins unconnected. If you are using a power supply that does not have a 24-pin connector, then you will need to purchase a new one.

No. 16. SATA
Serial ATA is a replacement for the parallel ATA interface (aka the aforementioned IDE). The SATA (Revision 1.0) interface has a bandwidth of 150 MB/s and offers backward compatibility for existing ATA devices. Distinctive feature is the absence of bulky cable bands (replaced by thin cables), which provides, in addition to greater throughput, also better air circulation in the case. New revisions of SATA provide bandwidth up to 800 MB / s. In addition to the internal SATA solution, it supports the connection of external SATA drives via the eSATA interface. The latter is very convenient and allows you to pick up a third-party screw without opening the case and transfer the necessary information at high speed.

Real time clock, non-volatile memory or CMOS RAM. CMOS (Complementary Metal Oxide Semiconductor) is a semiconductor chip powered by a round CMOS battery. It stores information such as the system date and time, as well as system settings for the computer's hardware components. To perform a full BIOS reset with restoring all factory settings, you must either remove the battery (and then put it back) or use the special ClearCMOS jumper. The average life of a CMOS battery is 10 years.

No. 18. -array
Special redundant controller-managed array of multiple disks designed to accelerate disk memory performance. Commonly used in servers and high performance PCs. Exists a large number of versions of RAID, each of which is designed to solve problems of increasing performance with its own methods. To take advantage of the increased disk performance, you must have at least two disks available.

No. 19. System panel connectors
FPanel or front panel connectors. This is what controls the operation of the power buttons, reset, LED "s (hard drive and power activity indicators), internal speaker. Front panel cables are systems of colored and b / w wires (black and white ground wires, color - power) .

No. 20. FWH (FirmWare Hub)
Is part of the architecture Intel Accelerated Hub Architecture, which contains the system BIOS and the integrated video BIOS (dedicated BIOS of the computer's video card) in one component. The hub connects directly to the I/O Controller Hub .

No. 21. Southbridge (southbridge)
The Southbridge (I/O Hub, ICH) is an integrated circuit that is responsible for managing hard drives, communicating with slow devices, expansion cards, and communicating with the Northbridge. The north and south bridges communicate with themselves via DMI, HyperTransport buses (which replaced PCI).

Most often, it is the south bridge that fails, taking all the blows (including thermal ones) of peripheral components first. If the “southerner” fails, then, as a rule, you will have to change the entire motherboard.

No. 22. Serial (COM) ports
An asynchronous port used to connect serial devices to a computer. Transmits one bit at a time.

The most common devices that can be connected to serial ports include:

• A mouse that does not have a PS/2 or USB connector;
• Modem;
• Network - which allows you to connect two computers together to transfer data m / a;
• Old printers and plotters.

No. 23. Port 1394 and USB port. 1394 header and USB header.
The FireWare port is designed to exchange digital information between PCs and other electronic devices. An important port for people who are fond of video filming, which allows you to transfer footage captured on the camera to a PC. Also port 1394 is used for video capture. It can be produced as a separate PCI IEEE1394 controller, or it can be integrated into the motherboard.

USB (universal serial bus) port - universal serial data bus for medium/low speed peripherals. This port allows you to connect peripherals without their own power source. In a modern PC, there can be up to 10-15 of them.

The 1394 header and USB header are the "pins" in older motherboards that were meant to connect additional ports, be it 1394 or USB. On the motherboard they look like this.

No. 24. Jumpers
Jumpers allow the computer to complete an electrical circuit and allow electricity to flow only to certain sections of the board. They consist of many small pins that can be wrapped in a plastic case. Jumpers are also used to configure the parameters of peripheral devices (hard drives, sound cards, etc.). Today, most users no longer need to manage jumpers on the motherboard, they are increasingly being used to set the primary (master) and secondary (slave) drive.

No. 25. Integrated circuit (integrated circuit)
A microchip is a pad containing many circuits, paths, transistors, and other electronic components that work together to perform a particular function or set of functions. Integrated circuits are the building blocks of computer hardware. This is what a microchip looks like on a printed circuit board.

No. 26. SPDIF
Digital Interconnect Format– an interface for transmitting compressed digital audio to audio equipment and home theater systems. The interface for audio transmission can use coaxial cable or fiber optic cable. Laptops and high-quality sound cards have this connector as a separate input / output. On the motherboard, it is signed as SPDIF_IO .

No. 27. CD IN
4 pin optical drive audio connector. CD-IN allows you to output sound directly from conventional CD-disks, drive.

Well, how do you like our voluminous manual on the stuffing of the motherboard? Impressive in my opinion. It is worth saying that many connectors and board components are already outdated and are now rarely found in modern motherboards, but it will be useful to know them at least.

SSD (and not only). Quite intelligible prices, although the range is not always ideal in terms of variety. The key advantage is the guarantee, which really allows you to change the goods within 14 days without any questions, and in case of warranty problems, the store will take your side and help solve any problems. The author of the site has been using it for at least 10 years (since the time when they were part of Ultra Electoronics), which he advises you;

, - one of the oldest stores on the market, as a company has been around for about 20 years. Decent selection, average prices and one of the most user friendly sites. In general, a pleasure to work with.

The choice is traditionally yours. Of course, no one canceled all sorts of Yandex.Market there, but from good stores, I would recommend these, and not some MVideo and other large networks there (which are often not just expensive, but flawed in terms of quality of service, warranty work etc.).

Afterword

Another technical note is ready and we hope that it will be really useful to someone. The cycle about motherboards does not end there yet, as well as articles on hardware in general.

Now you know what lives under the hood and you can quite quickly name any component located there, and this will greatly help your communication with the PC and make it truly personal.

Everything on the sim. Stay with us! ;)

PS: As always, we unsubscribe comments, questions and other miscellaneous things, then welcome to the comments.
PS2: For the existence of this article, thanks to a member of the 25 FRAME team.

The motherboard is the core of the computer. It contains the main electronic elements: processor, memory, BIOS, chipset, etc.

Motherboard types

All-In-One is a board that contains all the elements necessary for the operation of a computer. Motherboard (motherboard) - a board containing the main nodes and expansion connectors for installing daughter boards.

Motherboard Composition

On the motherboard are:

1. Sets of large single-chip electronic microcircuits - chips (central processing unit, other processors, integrated device controllers and their interfaces)

2. RAM chips and connectors of their boards

3. Electronic logic chips

4. Simple radio elements (transistors, capacitors, resistances, etc.)

5. System bus connectors (ISA, EISA, VESA, PCI, etc.)

6. Slots for connecting expansion cards (video cards or video adapters, sound cards, network cards, interfaces for peripheral devices IDE, EIDE, SCSI ...)

7. I/O port connectors (COM, LPT)

general characteristics

The motherboard is designed to accommodate or connect all other internal devices of the computer - it serves as a kind of platform on the basis of which the configuration of the entire system is built.

The type and characteristics of various elements and devices of the motherboard, as a rule, is determined by the type and architecture of the central processor (motherboards based on processors from Intel, AMD, Cyrix, etc. - 8086/8088/80188, 286, 386, 486/586/686 , Pentium, Pentium II-V As a rule, it is the central processor or processors, their family, type, architecture and performance that determine one or another architectural version of the motherboard.

According to the number of processors that make up the central processor, single-processor and multiprocessor (multiprocessor) motherboards are distinguished. Most personal computers are single-processor systems and come with single-processor motherboards.

Setting the motherboard to specific electronic components is carried out using jumpers (jumpers). In particular, these jumpers set the setting for a specific processor model - the clock frequency and supply voltage are regulated.

The motherboard is attached to the chassis of the system unit case, as a rule, with two screws with insulating plastic fasteners.

Modern requirements for motherboards

Modern motherboards are Energy Star compliant. This is an energy saving program introduced by the US Environmental Protection Agency (EPA - Environment Protection Agency). According to these requirements, the board is classified as "green" (green motherboard), if its power consumption in idle mode is not more than 30 W, it does not use toxic materials, 100% recycling is allowed after the expiration of its service life.

Consider the device of a typical Pentium-class motherboard with a 430HX chipset (ASUS P55T2P4 board).

1 – USB connector (USB header), 2 - mounting hole 3 – keyboard controller (keyboard controller), 4 - BIOS chip (flash BIOS ROM), 5 – ISA bus slot (ISA bus slot), 6 – PCI bus slot (PCI bus slot), 7 – multimedia expansion connector (mediabus slot), 8 - mounting hole 9 - a clock chip with a battery (real-time clock / CMOS), 10 – processor socket (CPU socket),

11 - voltage regulator, 12 – connectors for connecting housing indicators,

13 - capacitors, 14 – antistatic coating, 15 – switches (jumpers),

16 - Level 2 cache chips (cache chips), 17 – Cache expansion slot, 18 – Tag RAM expansion socket, 19 – Intel 430 HX chipset (chipset chips), 20 – memory module connectors (SIMM sockets), 21 - drive connector (floppy header), 22 – connector of the first IDE device (primary IDE header), 23 – connector of the second IDE device (secondary IDE header), 24 – power connector (power connector), 25 – I/O controller, 26 – parallel port connector (LPT header), 27 – 1 serial port connector (COM1 header), 28 – 2 serial port connector (COM2 header), 29 – PS2 port connector (PS2 mouse header), 30 – keyboard connector

The device and purpose of the motherboard

The motherboard or system board is a multilayer printed circuit board, which is the basis of a computer, which determines its architecture, performance and communicates between all elements connected to it and coordinates their work.

1. Introduction.

The motherboard is one of the most important elements of a computer, which determines its appearance and ensures the interaction of all devices connected to the motherboard.

The motherboard contains all the main elements of the computer, such as:

The system logic set or chipset is the main component of the motherboard, which determines what type of processor, type of RAM, type of system bus can be used;

Slot for installing the processor. Determines which type of processors can be connected to the motherboard. The processors may use different system bus interfaces (for example, FSB, DMI, QPI, etc.), some processors may have an integrated graphics system or memory controller, the number of "legs" may differ, and so on. Accordingly, for each type of processor, it is necessary to use its own slot for installation. Often, processor and motherboard manufacturers abuse this, chasing additional benefits, and create new processors that are not compatible with existing slot types, even if this could have been avoided. As a result, when updating a computer, it is necessary to change not only the processor, but also the motherboard, with all the ensuing consequences.

- central processing unit - the main computer device that performs mathematical, logical operations and control operations for all other elements of the computer;

RAM controller (random access memory). Previously, the RAM controller was built into the chipset, but now most processors have an integrated RAM controller, which allows you to increase overall performance and offload the chipset.

RAM is a set of chips for temporary storage of data. In modern motherboards, it is possible to connect several RAM chips at the same time, usually four or more.

PROM (BIOS) containing software, which tests the main components of the computer and configures the motherboard. And CMOS memory that stores BIOS settings. Often, several CMOS memory chips are installed to enable quick recovery of the computer in an emergency, for example, an unsuccessful overclocking attempt;

Rechargeable battery or battery that powers the CMOS memory;

I/O channel controllers: USB, COM, LPT, ATA, SATA, SCSI, FireWire, Ethernet, etc. Which I/O channels will be supported depends on the type of motherboard used. If necessary, additional I / O controllers can be installed in the form of expansion boards;

A quartz oscillator that generates signals by which the operation of all computer elements is synchronized;

Timers;

Interrupt controller. Interrupt signals from various devices do not go directly to the processor, but to the interrupt controller, which sets the interrupt signal with the appropriate priority to the active state;

Connectors for installing expansion cards: video cards, sound cards, etc.;

Voltage regulators that convert the source voltage into the required voltage to power the components installed on the motherboard;

Monitoring tools that measure the speed of rotation of fans, the temperature of the main elements of the computer, the supply voltage, etc.;

Sound card. Almost all motherboards contain built-in sound cards that allow you to get decent sound quality. If necessary, you can install an additional discrete sound card that provides better sound, but in most cases this is not required;

Built-in speaker. Mainly used to diagnose system health. So, by the duration and sequence of sound signals when the computer is turned on, most equipment malfunctions can be determined;

Tires are conductors for the exchange of signals between computer components.

2. PCB.

The basis of the motherboard is the printed circuit board. On the printed circuit board are signal lines, often called signal tracks, interconnecting all elements of the motherboard. If the signal paths are too close to each other, then the signals transmitted along them will interfere with each other. The longer the track and the higher the data rate on it, the more it interferes with neighboring tracks and the more it is vulnerable to such interference.

As a result, there may be failures in the operation of even ultra-reliable and expensive computer components. Therefore, the main task in the production of a printed circuit board is to place the signal tracks in such a way as to minimize the effect of interference on the transmitted signals. To do this, the printed circuit board is made multilayer, multiplying the useful area of ​​the printed circuit board and the distance between the tracks.

Typically, modern motherboards have six layers: three signal layers, a ground layer, and two power plates.

However, the number of power layers and signal layers can vary depending on the features of motherboards.

The layout and length of the tracks is extremely important for normal operation of all computer components, therefore, when choosing a motherboard, special attention should be paid to the quality of the printed circuit board and the layout of the tracks. This is especially important if you are going to use computer components with non-standard settings and operation parameters. For example, overclock the processor or memory.

The printed circuit board contains all the components of the motherboard and connectors for connecting expansion cards and peripherals. The figure below shows a block diagram of the location of components on a printed circuit board.

Let's take a closer look at all the components of the motherboard and start with the main component - the chipset.

3. Chipset.

A chipset or system logic set is the main motherboard chipset that provides the combined operation of the central processor, RAM, video card, peripheral controllers and other components connected to the motherboard. It is he who determines the main parameters of the motherboard: the type of supported processor, the volume, channel and type of RAM, the frequency and type of the system bus and memory bus, sets of peripheral device controllers, and so on.

As a rule, modern chipsets are built on the basis of two components, which are separate chipsets connected to each other by a high-speed bus.

However recent times there has been a tendency to combine the north and south bridges into a single component, as the memory controller is increasingly built directly into the processor, thereby unloading the north bridge, and faster and faster communication channels with peripherals and expansion cards appear. And the technology of manufacturing integrated circuits is also developing, allowing them to be made smaller, cheaper and consuming less energy.

Combining the northbridge and southbridge into one chipset improves system performance by reducing the interaction time with peripherals and internal components previously connected to the southbridge, but significantly complicates the design of the chipset, makes it more difficult to upgrade and slightly increases the cost of the motherboard.

But so far, most motherboards are made on the basis of a chipset divided into two components. These components are called the North and South Bridge.

The names North and South are historical. They indicate the location of the chipset components relative to the PCI bus: North is higher, and South is lower. Why a bridge? This name was given to the chipsets for the functions they perform: they serve to connect various buses and interfaces.

The reasons for splitting the chipset into two parts are as follows:

1. Differences in high-speed modes of operation.

The northbridge handles the fastest and busiest components. These components include the graphics card and memory. However, today most processors have an integrated memory controller, and many also have an integrated graphics system, although it is much inferior to discrete video cards, but still often used in budget personal computers, laptops and netbooks. Therefore, every year the load on the northbridge is reduced, which reduces the need to split the chipset into two parts.

2. More frequent updating of the standards of the periphery than the main parts of the computer.

The standards for communication buses with memory, video card and processor change much less often than the standards for communication with expansion cards and peripherals. This allows, in case of a change in the communication interface with peripheral devices or the development of a new communication channel, not to change the entire chipset, but to replace only the south bridge. In addition, the northbridge works with faster devices and is more complex than the southbridge, since the overall performance of the system largely depends on its operation. So changing it is expensive and hard work. But, despite this, there is a tendency to combine the north and south bridges into one integrated circuit.

3.1. Main functions of the North Bridge.

The Northbridge, as its name implies, performs the functions of controlling and directing the data flow from 4 buses:

1. Bus communication with the processor or system bus.
2. Buses of communication with memory.
3. Communication buses with the graphics adapter.
4. Communication buses with the south bridge.

In accordance with the functions performed, the north bridge was arranged. It consists of system bus interface, southbridge communication bus interface, memory controller, graphics card communication bus interface.

At the moment, most processors have an integrated memory controller, so the memory controller function can be considered obsolete for the northbridge. And given that there are many types of RAM, we will single out a separate article to describe the memory and the technology of its interaction with the processor.

In budget computers, a graphics system is sometimes built into the north bridge. However, at the moment, it is more common practice to install a graphics system directly into the processor, so we will also consider this northbridge function obsolete.

Thus, the main task of the chipset is to competently and quickly distribute all requests from the processor, video card and southbridge, set priorities and create, if necessary, a queue. Moreover, it should be so balanced as to reduce downtime as much as possible when trying to access computer components to certain resources.

Let's consider in more detail the existing communication interfaces with the processor, graphics adapter and south bridge.

3.1.1. Communication interfaces with the processor.

At the moment, there are the following interfaces for connecting the processor with the northbridge: FSB, DMI, HyperTransport, QPI.

FSB (Front Site Bus)- the system bus used to connect the CPU to the northbridge in the 1990s and 2000s. FSB was developed by Intel and was first used in computers based on Pentium processors.

The frequency of the FSB bus is one of the most important parameters of the computer and largely determines the performance of the entire system. Usually it is several times less than the frequency of the processor.

The frequencies at which the central processor and the system bus operate have a common reference frequency and are calculated in a simplified form as Vp = Vo*k, where Vp is the processor operating frequency, Vo is the reference frequency, k is the multiplier. Usually in modern systems the reference frequency is equal to the FSB frequency.

Most motherboards allow you to manually increase the system bus frequency or multiplier by changing settings in the BIOS. In older motherboards, these settings were changed by swapping jumpers. Increasing the system bus frequency or multiplier increases the performance of the computer. However, in most modern processors of the middle price category, the multiplier is locked, and the only way to improve the performance of a computing system is to increase the frequency of the system bus.

The FSB frequency gradually increased from 50 MHz for Intel Pentium and AMD K5 class processors in the early 1990s to 400 MHz for Xeon and Core 2 class processors in the late 2000s. At the same time, the bandwidth increased from 400 Mbps to 12800 Mbps.

The FSB was used in Atom, Celeron, Pentium, Core 2, and Xeon processors until 2008. At the moment, this bus has been superseded by the DMI, QPI, and Hyper Transport system buses.

HyperTransport– a universal high-speed point-to-point bus with low latency, used to connect the processor with the northbridge. The HyperTransport bus is bidirectional, that is, its own communication line is allocated for the exchange in each direction. In addition, it works on DDR (Double Data Rate) technology, transmitting data both on the front and on the fall of the clock pulse.

The technology was developed by the HyperTransport Technology consortium led by AMD. It is worth noting that the HyperTransport standard is open, which allows various companies to use it in their devices.

The first version of HyperTransport was introduced in 2001, and allowed to exchange at a speed of 800 MTP / s (800 Mega Transactions per second or 838860800 exchanges per second) with a maximum throughput of 12.8 GB / s. But already in 2004, a new modification of the HyperTransport bus (v.2.0) was released, providing 1.4 GTr/s with a maximum throughput of 22.4 GB/s, which was almost 14 times higher than the capabilities of the FSB bus.

On August 18, 2008, modification 3.1 was released, operating at a speed of 3.2 GTr / s, with a throughput of 51.6 GB / s. This is currently the fastest version of the HyperTransport bus.

HyperTransport technology is very flexible and allows you to vary both the bus frequency and its bit depth. This allows you to use it not only to connect the processor with the north bridge and RAM, but also in slow devices. At the same time, the possibility of reducing the bit depth and frequency leads to energy savings.

The minimum bus clock frequency is 200 MHz, while data will be transferred at a speed of 400 MTP / s, due to DDR technology, and the minimum bit depth is 2 bits. With the minimum settings, the maximum throughput will be 100 MB/s. All the following supported frequencies and bit depths are multiples of the minimum clock frequency and bit depth up to speed - 3.2 GTr/s, and bit depth - 32 bits, for HyperTransport v 3.1 revision.

DMI (Direct Media Interface)– a point-to-point serial bus used to connect the processor to the chipset and to connect the southbridge of the chipset with the northbridge. Developed by Intel in 2004.

4 DMI channels are usually used to communicate with the chipset, providing a maximum throughput of up to 10 GB / s for the DMI 1.0 revision, and 20 GB / s for the DMI 2.0 revision, introduced in 2011. In budget mobile systems, a bus with two DMI channels can be used, which reduces the bandwidth by half compared to a 4-channel option.

Often, in processors that communicate with the chipset via the DMI bus, along with a memory controller, a PCI Express bus controller is built in, which provides interaction with the video card. In this case, there is no need for a northbridge, and the chipset performs only the functions of interaction with expansion cards and peripheral devices. With this architecture of the motherboard, a high-speed channel is not required to interact with the processor, and the bandwidth of the DMI bus is more than enough.

QPI (QuickPath Interconnect)– a point-to-point serial bus used to communicate processors with each other and with the chipset. Introduced by Intel in 2008 and used in HiEnd processors such as Xeon, Itanium and Core i7.

The QPI bus is bidirectional, that is, there is a separate channel for exchange in each direction, each of which consists of 20 communication lines. Therefore, each channel is 20 bits, of which only 16 bits per payload. The QPI bus operates at speeds of 4.8 and 6.4 GTr/s, while the maximum throughput is 19.2 and 25.6 GB/s, respectively.

We briefly reviewed the main communication interfaces between the processor and the chipset. Next, consider the communication interfaces of the North Bridge with a graphics adapter.

3.1.2. Communication interfaces with the graphic adapter.

At first, a common ICA, VLB, and then PCI bus was used to communicate with the GPU, but very quickly the bandwidth of these buses was no longer enough to work with graphics, especially after the spread of three-dimensional graphics, which requires huge computing power and high bus bandwidth for transmission textures and image parameters.

The common buses were replaced by a specialized AGP bus, optimized for working with a graphics controller.

AGP (Accelerated Graphics Port)- a specialized 32-bit bus for working with a graphics adapter, developed in 1997 by Intel.

The AGP bus operated at a clock frequency of 66 MHz and supported two modes of operation: with DMA (Direct Memory Access) memory and DME (Direct in Memory Execute) memory.

In DMA mode, the memory built into the video adapter was considered the main memory, and in the DME mode, the memory of the video card, which, together with the main memory, were in a single address space, and the video adapter could access both the built-in memory and the main memory of the computer.

The presence of the DME mode made it possible to reduce the amount of memory built into the video adapter and thereby reduce its cost. The DME memory mode is called AGP texturing.

However, very soon the bandwidth of the AGP bus was no longer enough to work in DME mode, and manufacturers began to increase the amount of built-in memory. Soon, the increase in built-in memory ceased to help, and the bandwidth of the AGP bus became categorically lacking.

The first version of the AGP bus, AGP 1x, operated at a clock frequency of 66 MHz and had a maximum data transfer rate of 266 MB / s, which was not enough for full-fledged operation in DME mode and did not exceed the speed of its predecessor, the PCI bus (PCI 2.1 - 266 MB/s). Therefore, almost immediately, the bus was finalized and the data transfer mode was introduced at the front and the fall of the clock pulse, which, at the same clock frequency of 66 MHz, made it possible to obtain a throughput of 533 MB / s. This mode was called AGP 2x.

The first revision of AGP 1.0 introduced to the market supported AGP 1x and AGP 2x modes of operation.

In 1998, a new revision of the bus, AGP 2.0, was introduced, supporting the AGP 4x mode of operation, in which 4 data blocks were already transferred per cycle, as a result, the throughput reached 1 GB / s.

At the same time, the reference clock frequency of the bus did not change and remained equal to 66 MHz, and for the possibility of transmitting four data blocks in one cycle, an additional signal was introduced that starts synchronously with the reference clock frequency, but at a frequency of 133 MHz. The data was transmitted along the rise and fall of the clock pulse of the additional signal.

At the same time, the supply voltage was reduced from 3.3 V to 1.5 V, as a result, video cards released only for the AGP 1.0 revision were incompatible with AGP 2.0 video cards and the next revisions of the AGP bus.

In 2002, revision 3.0 of the AGP bus was released. The bus reference still remained unchanged, but the additional clock pulse, which started synchronously with the reference, was already 266 MHz. At the same time, 8 blocks were transmitted per 1 cycle of the reference frequency, and the maximum speed was 2.1 GB / s.

But, despite all the improvements in the AGP bus, video adapters developed faster and required a more efficient bus. So the AGP bus was replaced by the PCI express bus.

PCI express is a point-to-point bi-directional serial bus developed in 2002 by the non-profit group PCI-SIG, which included campaigns such as Intel, Microsoft, IBM, AMD, Sun Microsystems, and others.

The main task facing the PCI express bus is to replace the AGP graphics bus and the parallel universal PCI bus.

The revision of the PCI express 1.0 bus operates at a clock frequency of 2.5 GHz, while the total bandwidth of one channel is 400 MB / s, since for every 8 data bits transmitted there are 2 service bits and the bus is bidirectional, that is, the exchange goes both ways simultaneously. The bus typically uses multiple channels: 1, 2, 4, 8, 16, or 32, depending on the bandwidth required. Thus, PCI express-based buses in general case are a set of independent serial data channels.

So, when using the PCI express bus, a 16-channel bus is usually used for communication with video cards, and a single-channel bus is used for communication with expansion cards.

The theoretical maximum total throughput of a 32-channel bus is 12.8 GB/s. At the same time, unlike the PCI bus, which divided the bandwidth between all connected devices, the PCI express bus is built on the principle of a star topology, and each connected device is given sole ownership of the entire bus bandwidth.

In the PCI express 2.0 revision, introduced on January 15, 2007, the bus bandwidth was doubled. For one bus channel, the total throughput was 800 MB/s, and for a 32-channel bus, 25.6 GB/s.

In the revision of PCI express 3.0, presented in November 2010, the bus bandwidth was increased by 2 times, and maximum amount transactions increased from 5 to 8 billion, and the maximum throughput increased by 2 times, due to a change in the principle of information encoding, in which there are only 2 service bits for every 129 bits of data, which is 13 times less than in revisions 1.0 and 2.0. Thus, for one bus channel, the total throughput became 1.6 GB / s, and for a 32-channel bus - 51.2 GB / s.

However, PCI express 3.0 is only just entering the market, and the first motherboards supporting this bus began to appear at the end of 2011, and mass production of devices supporting the PCI express 3.0 bus is scheduled for 2012.

It should be noted that at the moment the bandwidth of PCI express 2.0 is quite enough for the normal functioning of video adapters and the transition to PCI express 3.0 will not give a significant increase in performance in the processor-video card combination. But, as they say, wait and see.

In the near future, we plan to release a revision of PCI express 4.0, in which the speed will be increased by 2 times.

Recently, there has been a trend of embedding the PCI express interface directly into the processor. Typically, such processors also have a built-in memory controller. As a result, there is no need for a north bridge, and the chipset is built on the basis of a single integrated circuit, the main task of which is to provide interaction with expansion cards and peripheral devices.

This concludes the review of the communication interfaces of the north bridge with the video adapter and proceed to the review of the communication interfaces of the north bridge with the south.

3.1.3. Communication interfaces with the south bridge.

For quite a long time, the PCI bus was used to connect the north bridge with the south bridge.

PCI (Peripheral Component Interconnect) is a bus for connecting expansion cards to the motherboard, developed in 1992 by Intel. It was also used for a long time to connect the north bridge with the south. However, as the performance of expansion boards increased, its bandwidth became insufficient. It was supplanted by more efficient tires at first from the tasks of connecting the north and south bridges, and in last years and for communication with expansion cards they began to use a faster bus - PCI express.

Main specifications PCI buses are as follows:

revision	1.0	2.0	2.1	2.2	2.3
date of release	1992	1993	1995	1998	2002
Bit depth	32	32	32/64	32/64	32/64
Frequency	33 MHz	33 MHz	33/66 MHz	33/66 MHz	33/66 MHz
Bandwidth	132 MB/s	132 MB/s	132/264/528 MB/s	132/264/528 MB/s	132/264/528 MB/s
Signal voltage	5 V	5 V	5/3.3V	5/3.3V	5/3.3V
Hot swap	No	No	No	there is	there is

There are other revisions of PCI buses, for example, for use in laptops and other portable devices, or transitional options between major revisions, but since at the moment the PCI interface has been almost replaced by faster buses, I will not describe in detail the characteristics of all revisions.

When using a bus to connect the north and south bridge, the block diagram of the motherboard will look like this:

As can be seen from the figure, the north and south bridges were connected to the PCI bus on a par with expansion cards. The bandwidth of the bus was shared among all devices connected to it, and, consequently, the declared peak bandwidth was reduced not only by the transmitted service information, but also by competing devices connected to the bus. As a result, over time, the bus bandwidth began to pick up, and for communication between the north and south bridges, buses such as hub link, DMI, HyperTransport began to be used, and the PCI bus remained for a short time as a connection with expansion cards.

The hub link bus was the first to replace PCI.

hublink bus– An 8-bit point-to-point bus developed by Intel. The bus operates at a frequency of 66 MHz and transfers 4 bytes per clock, which allows you to get a maximum throughput of 266 MB / s.

The introduction of the hublink bus changed the architecture of the motherboard and offloaded the PCI bus. The PCI bus became used only for communication with peripherals and expansion cards, and the hublink bus was used only for communication with the northbridge.

The bandwidth of the hublink bus was comparable to the bandwidth of the PCI bus, but due to the fact that it did not have to share a channel with other devices, and the PCI bus was offloaded, the bandwidth was quite sufficient. But computing technology does not stand still, and the hublink bus is practically not used at the moment, due to insufficient speed. It has been superseded by buses such as DMI and HyperTransport.

A brief description of the DMI bus and HyperTransport was given in the section, so I will not repeat it.

There were other interfaces for connecting the north bridge to the south, but most of them are already hopelessly outdated or rarely used, so we will not focus on them. This concludes the review of the main functions and structure of the north bridge and move on to the south bridge.

3.2. The main functions of the South Bridge.

The south bridge is responsible for organizing interaction with slow computer components: expansion cards, peripherals, input-output devices, machine-to-machine exchange channels, and so on.

That is, the Southbridge relays data and requests from devices connected to it to the Northbridge, which transfers them to the processor or RAM, and receives processor commands and data from RAM from the Northbridge, and relays them to devices connected to it.

The south bridge includes:

Northbridge communication bus controller (PCI, hublink, DMI, HyperTransport, etc.);

Communication bus controller with expansion cards (PCI, PCIe, etc.);

Controller of communication lines with peripheral devices and other computers (USB, FireWire, Ethernet, etc.);

Hard drive communication bus controller (ATA, SATA, SCSI, etc.);

Communication bus controller with slow devices (ISA, LPC, SPI buses, etc.).

Let's take a closer look at the communication interfaces used by the south bridge and the controllers of peripheral devices built into it.

We have already considered the communication interfaces of the north bridge with the south. Therefore, we will immediately move on to the communication interfaces with expansion boards.

3.2.1. Communication interfaces with expansion boards.

At the moment, the main interfaces for exchanging with expansion cards are PCI and PCIexpress. However, the PCI interface is being actively replaced, and in the next few years it will practically disappear into history, and will be used only in some specialized computers.

I have already given a description and brief characteristics of the PCI and PCIexpress interfaces in this article, so I will not repeat myself. Let's proceed directly to the consideration of communication interfaces with peripheral devices, input-output devices and other computers.

3.2.2. Communication interfaces with peripheral devices, input-output devices and other computers.

There is a wide variety of interfaces for communication with peripherals and other computers, the most common of them are built into the motherboard, but you can also add any of the interfaces using expansion cards connected to the motherboard via the PCI or PCIexpress bus.

I will bring short description and characteristics of the most popular interfaces.

USB (Universal Serial Bus)- a universal serial data transmission channel for connecting medium-speed and low-speed peripheral devices to a computer.

The bus is strictly oriented and consists of a channel controller and several terminal devices connected to it. Typically, USB channel controllers are built into the southbridge of the motherboard. Modern motherboards can accommodate up to 12 USB channel controllers with two ports each.

It is not possible to connect two channel controllers or two end devices together, so you cannot directly connect two computers or two peripheral devices to each other via USB.

However, additional devices can be used to communicate between two channel controllers. For example, an Ethernet adapter emulator. Two computers connect to it via USB, and both see the end device. An Ethernet adapter relays data received from one computer to another by emulating the Ethernet network protocol. However, it is necessary to install specific drivers for the Ethernet adapter emulator on each connected computer.

The USB interface has built-in power lines, which makes it possible to use devices without their own power supply or simultaneously recharge the batteries of terminal devices, such as telephones, while exchanging data.

However, if a USB hub is used between the channel controller and the end device, then it must have additional external power to provide all devices connected to it with the power required by the USB interface standard. If you use a USB hub without an additional power source, then if you connect several devices without their own power sources, they most likely will not work.

USB supports hot plugging of end devices. This is possible due to the longer ground contact than the signal contacts. Therefore, when connecting the terminal device, the ground contacts are first closed, and the potential difference between the computer and the terminal device is equalized. Therefore, further connection of the signal conductors does not lead to a voltage surge.

There are currently three major revisions of the USB interface (1.0, 2.0 and 3.0). Moreover, they are compatible from the bottom up, that is, devices designed for revision 1.0 will work with the revision 2.0 interface, respectively, devices designed for USB 2.0 will work with USB 3.0, but devices for USB 3.0 will most likely not work with USB 2.0 interface.

Consider the main characteristics of the interface, depending on the revision.

USB 1.0 is the first version of the USB interface, released in November 1995. In 1998, the revision was finalized, errors and shortcomings were eliminated. The resulting USB 1.1 revision was the first to be widely adopted.

Specifications for revisions 1.0 and 1.1 are as follows:

Data transfer rate - up to 12 Mbps (Full-Speed ​​mode) or 1.5 Mbps (Low-Speed ​​mode);

The maximum cable length is 5 meters for Low-Speed ​​mode, and 3 meters for Full-Speed ​​mode;

USB 2.0 is a revision released in April 2000. The main difference from the previous version is the increase in the maximum data transfer rate to 480 Mbps. In practice, due to the large delays between the request for data transmission and the start of transmission, speeds of 480 Mbps cannot be achieved.

The technical specifications of revision 2.0 are as follows:

Data transfer rate - up to 480 Mbps (Hi-speed), up to 12 Mbps (Full-Speed ​​mode) or up to 1.5 Mbps (Low-Speed ​​mode);

Synchronous data transmission (on request);

Half-duplex exchange (simultaneous transmission is possible only in one direction);

The maximum cable length is 5 meters;

The maximum number of devices connected to one controller (including multipliers) is 127;

It is possible to connect devices operating in different bandwidth modes to one USB controller;

Supply voltage for peripheral devices - 5 V;

Maximum current - 500 mA;

The cable consists of four communication lines (two lines for receiving and transmitting data, and two lines for powering peripheral devices) and a ground braid.

USB 3.0 is a revision released in November 2008. In the new revision, the speed was increased by an order of magnitude, up to 4800 Mbps, and the current strength was almost doubled, up to 900 mA. At the same time, it changed a lot appearance connectors and cables, but bottom-up compatibility remained. Those. devices that work with USB 2.0 will be able to connect to the 3.0 connector and will work.

The technical specifications of revision 3.0 are as follows:

Data transfer rates - up to 4800 Mbps (SuperSpeed ​​mode), up to 480 Mbps (Hi-speed mode), up to 12 Mbps (Full-Speed ​​mode), or up to 1.5 Mbps (Low-Speed ​​mode) );

Dual bus architecture (Low-Speed/Full-Speed/High-Speed ​​bus and separate SuperSpeed ​​bus);

Asynchronous data transfer;

Duplex exchange in SuperSpeed ​​mode (simultaneous transmission and reception of data is possible) and simplex in other modes.

The maximum cable length is 3 meters;

The maximum number of devices connected to one controller (including multipliers) is 127;

Supply voltage for peripheral devices - 5 V;

Maximum current - 900 mA;

Improved power management system to save energy when end devices are idle;

The cable consists of eight communication lines. The four communication lines are the same as in USB 2.0. Additional two communication lines for receiving data and two for SuperSpeed ​​transmission, and two ground braids: one for Low-Speed ​​/ Full-Speed ​​/ High-Speed ​​data cables, and one for cables, used in SuperSpeed ​​mode.

IEEE 1394 (Institute of Electrical and Electronic Engineers) is a serial high-speed bus standard adopted in 1995. Tires designed to this standard are named differently by different companies. Apple has FireWire, Sony has i.LINK, Yamaha has mLAN, Texas Instruments has Lynx, Creative has SB1394, and so on. Because of this, confusion often arises, but despite the different names, this is the same bus operating according to the same standard.

This bus is designed to connect high-speed peripherals such as external hard drives, digital camcorders, music synthesizers, and so on.

The main technical characteristics of the tire are as follows:

The maximum data transfer rate varies from 400 Mbps, for the IEEE 1394 revision, to 3.2 Gbps, for the IEEE 1394b revision;

The maximum communication length between two devices varies from 4.5 meters for IEEE 1394 revision to 100 meters for IEEE 1394b revision and older;

The maximum number of devices connected in series to one controller is 64, including IEEE hubs. In this case, all connected devices share the bus bandwidth. Each IEEE hub can connect up to 16 more devices. Instead of connecting a device, you can connect a bus jumper, through which you can connect another 63 devices. In total, you can connect up to 1023 bus jumpers, which will allow you to organize a network of 64,449 devices. More devices cannot be connected, since in the IEEE 1394 standard each device has a 16-bit address;

Ability to network multiple computers;

Hot connection and disconnection of devices;

Ability to use bus-powered devices that do not have their own power supply. Wherein maximum strength current - up to 1.5 Amperes, and voltage - from 8 to 40 Volts.

ethernet– a standard for building computer networks based on technology burst transmission data, developed in 1973 by Robert Metclough of Xerox PARC Corporation.

The standard defines the types of electrical signals and the rules of wired connections, describes frame formats and data transfer protocols.

There are dozens of different revisions of the standard, but the most common today is a group of standards: Fast Ethernet and Gigabit Ethernet.

Fast Ethernet provides data transfer at speeds up to 100 Mbps. And the data transmission range in one network segment without repeaters is from 100 meters (100BASE-T standard group using twisted pair for data transmission) to 10 kilometers (100BASE-FX standard group using single-mode fiber for data transmission).

Gigabit Ethernet provides data transfer rates up to 1 Gbps. And the data transmission range in one network segment without repeaters is from 100 meters (1000BASE-T standard group, using four twisted pairs for data transmission) to 100 kilometers (1000BASE-LH standard group, using single-mode fiber for data transmission).

To transfer large amounts of information, there are standards for ten, forty and one hundred gigabit Ethernet, operating on the basis of fiber optic communication lines. But more details about these standards and about Ethernet technology in general will be described in a separate article on machine-to-machine communication.

WiFi- a wireless communication line created in 1991 by the Netherlands company NCR Corporation / AT&T. WiFi is based on the IEEE 802.11 standard. and is used both for communication with peripheral devices and for organizing local networks.

Wi-Fi allows you to connect two computers or a computer and a peripheral device directly using point-to-point technology, or organize a network using an access point, to which several devices can connect at the same time.

The maximum data transfer rate depends on the revision of the IEEE 802.11 standard used, but in practice it will be significantly lower than the declared parameters, due to overhead costs, the presence of obstacles in the signal propagation path, the distance between the signal source and the receiver, and other factors. In practice, the average throughput at best will be 2-3 times less than the declared maximum throughput.

Depending on the revision of the standard, the Wi-Fi throughput is as follows:

Standard revision	Clock frequency	Claimed maximum power	Average data rate in practice	Communication range indoor/outdoor
802.11a	5 GHz	54 Mbps	18.4 Mbps	35/120 m
802.11b	2.4GHz	11 Mbps	3.2 Mbps	38/140 m
802.11g	2.4GHz	54 Mbps	15.2 Mbps	38/140 m
802.11n	2.4 or 5 GHz	600 Mbps	59.2 Mbps	70/250 m

There are many other interfaces for communicating with peripheral devices and organizing local networks. However, they are rarely built into the motherboard and are usually used as expansion boards. Therefore, these interfaces, along with those described above, will be considered in the article devoted to machine-to-machine interaction, and now let's move on to describing the communication interfaces of the south bridge with hard drives.

3.2.3. Southbridge communication bus interfaces with hard drives.

Initially, the ATA interface was used to communicate with hard drives, but later it was supplanted by the more convenient and modern SATA and SCSI interfaces. We give a brief overview of these interfaces.

ATA (Advanced Technology Attachment) or PATA (Parallel ATA) is a parallel communication interface developed in 1986 by Western Digital. At that time it was called IDE (Integrated Drive Electronics), but later it was renamed to ATA, and with the advent of the SATA interface in 2003, PATA was renamed to PATA.

Using the PATA interface implies that the hard disk controller is not located on the motherboard or in the form of an expansion card, but is built into the hard disk itself. On the motherboard, namely in the south bridge, there is only a PATA channel controller.

To connect hard drives with a PATA interface, a 40-wire cable is usually used. With the introduction of the PATA / 66 mode, its 80-wire version appeared. The maximum length of the loop is 46 cm. Two devices can be connected to one loop, while one of them must be the master and the other the slave.

There are several revisions of the PATA interface, differing in data transfer speed, operating modes and other features. Below are the main revisions of the PATA interface.

In practice, the bus bandwidth is much lower than the declared theoretical bandwidth, due to the overhead of organizing the exchange protocol and other delays. In addition, if two hard drives are connected to the bus, then the bandwidth will be divided between them.

In 2003, the SATA interface replaced the PATA interface.

SATA (Serial ATA)- a serial interface for connecting the south bridge to hard drives, developed in 2003.

When using the SATA interface, each drive is connected with its own cable. Moreover, the cable is much narrower and more convenient than the cable used in the PATA interface, and has a maximum length of up to 1 meter. A separate cable supplies power to the hard drive.

And even despite the fact that the total number of cables increases compared to the PATA interface, since each drive is connected with two cables, there is much more free space inside the system unit. This leads to an improvement in the efficiency of the cooling system, simplifies access to various elements of the computer, and the system unit looks more presentable from the inside.

At the moment, there are three main revisions of the SATA interface. The table below shows the main revision parameters.

Separate from these interfaces is the SCSI interface.

SCSI (Small Computer System Interface)- a universal bus for connecting high-speed devices such as hard drives, DVD and Blue-Ray drives, scanners, printers, and so on. The bus has a high bandwidth, but is complex and expensive. Therefore, it is mainly used in servers and industrial computing systems.

The first revision of the interface was introduced in 1986. At the moment there are about 10 tire revisions. The table below shows the main parameters of the most popular revisions.

Interface revision	Bit depth	Communication frequency	Max. throughput	Cable length (m)	Max. number of devices	release year
SCSI-1	8 bit	5 MHz	40 Mbps	6	8	1986
SCSI-2	8 bit	10 MHz	80 Mbps	3	8	1989
SCSI-3	8 bit	20 MHz	160 Mbps	3	8	1992
Ultra-2SCSI	8 bit	40 MHz	320 Mbps	12	8	1997
Ultra-3SCSI	16 bit	80 MHz	1.25 Gbps	12	16	1999
Ultra-320SCSI	16 bit	160 MHz	2.5 Gbps	12	16	2001
Ultra-640SCSI	16 bit	320 MHz	5 Gbps	12	16	2003

Increasing the throughput of a parallel interface is associated with a number of difficulties, and, first of all, it is protection against electromagnetic interference. And each communication line is a source of electromagnetic interference. The more communication lines there are in the parallel bus, the more they will interfere with each other. The higher the data transmission frequency, the more electromagnetic interference, and the more they affect data transmission.

In addition to this problem, there are less significant ones, such as:

• complexity and high cost of parallel bus production;
• problems in synchronous data transmission over all bus lines;
• the complexity of the device and the high price of bus controllers;
• the complexity of organizing a full-duplex device;
• the complexity of providing each device with its own bus, etc.

As a result, it is easier to abandon the parallel interface in favor of a serial interface with a higher clock speed. If necessary, several serial communication lines can be used, located further from each other and protected by a shielding braid. This was done during the transition from a parallel PCI bus to a serial PCI express, from PATA to SATA. The SCSI bus followed the same development path. So in 2004, the SAS interface appeared.

SAS (Serial Attached SCSI) point-to-point serial bus that replaced the parallel SCSI bus. For exchange over the SAS bus, the SCSI command model is used, but the throughput is increased to 6 Gb / s (SAS revision 2, released in 2010).

In 2012, it is planned to release a revision of SAS 3, which has a bandwidth of 12 Gb / s, however, devices that support this revision will not begin to appear en masse until 2014.

Also, do not forget that the SCSI bus was shared, allowing you to connect up to 16 devices, and all devices shared the bus bandwidth. And the SAS bus uses a point-to-point topology. And, therefore, each device is connected by its own communication line and receives the entire bus bandwidth.

The SCSI and SAS controller is rarely built into the motherboard, as they are quite expensive. Usually they are connected as expansion cards to the PCI or PCI express bus.

3.2.4. Communication interfaces with slow motherboard components.

To communicate with slow motherboard components, such as custom ROM or low-speed interface controllers, specialized buses are used, such as: ISA, MCA, LPS and others.

The Industry Standard Architecture (ISA) bus is a 16-bit bus developed in 1981. ISA ran at a clock speed of 8 MHz and had a throughput of up to 8 MB/s. The tire has long been outdated and is not used in practice.

An alternative to the ISA bus was the MCA (Micro Channel Architecture) bus, developed in 1987 by Intel. This bus was 32-bit with a data transfer rate of 10 MHz and a bandwidth of up to 40 Mbps. Supported Plug and Play technology. However, the closed nature of the bus and IBM's strict licensing policy made it unpopular. At the moment, the bus is not used in practice.

The real replacement for ISA was the LPC (Low Pin Count) bus, developed by Intel in 1998 and used to this day. The bus operates at a clock frequency of 33.3 MHz, which provides a throughput of 16.67 Mbps.

The bus bandwidth is quite small, but it is quite sufficient for communication with slow motherboard components. Using this bus, a multifunctional controller (Super I / O) is connected to the south bridge, which includes controllers for slow communication interfaces and peripheral devices:

• parallel interface;
• serial interface;
• infrared port;
• PS/2 interface;
• floppy disk drive and other devices.

The LPC bus also provides access to the BIOS, which we will talk about in the next part of our article.

4. BIOS (Basic Input-Output System).

BIOS (Basic Input-Output System - basic input-output system) is a program that is flashed into read-only memory (ROM). In our case, the ROM is built into the motherboard, but its own version of the BIOS is present in almost all elements of the computer (in the video card, in the network card, disk controllers, etc.), and in general in almost all electronic equipment (both in the printer and in a camcorder, and in a modem, etc.).

The motherboard BIOS is responsible for checking the functionality of the controllers built into the motherboard and most of the devices connected to it (processor, memory, video card, hard drives, etc.). The Power-On Self Test (POST) is checked when the computer is powered on.

Next, the BIOS initializes the controllers built into the motherboard and some devices connected to them, and sets their basic operation parameters, for example, the frequency of the system bus, processor, RAM controller, hard drives, controllers built into the motherboard, etc. d.

If the controllers and hardware being tested are healthy and configured, then the BIOS transfers control to the operating system.

Users can manage most of the BIOS settings and even update it.

A BIOS update is very rarely required if, for example, the developers have discovered and fixed a fundamental error in the initialization program of any of the devices, or if support for a new device (for example, a new processor model) is required. But, in most cases, the release of a new type of processor or memory requires a cardinal “upgrade” of the computer. Let's say "thank you" to electronics manufacturers for this.

To configure the BIOS settings, a special menu is provided, which can be entered by pressing the key combination indicated on the monitor screen during the POST tests. Usually, you need to press the DEL key to enter the BIOS setup menu.

In this menu, you can set the system time, drive and hard drive settings, increase (or decrease) the clock speed of the processor, memory and system bus, communication buses, and configure other computer settings. However, you should be extremely careful here, as incorrectly set parameters can lead to errors in operation or even disable the computer.

All BIOS settings are stored in volatile CMOS memory, powered by a battery or an accumulator installed on the motherboard. If the battery or accumulator is dead, the computer may not turn on or may not work properly. For example, the system time will be set incorrectly or the operation parameters of some devices will be set.

5. Other elements of the motherboard.

In addition to the elements described above, there is a clock frequency generator on the motherboard, consisting of a quartz resonator and a clock generator. The clock frequency generator consists of two parts, since the quartz resonator is not able to generate pulses at the frequency required for the operation of modern processors, memory and buses, so the clock frequency generated by the quartz resonator is changed using a clock generator that multiplies or divides the original frequencies to obtain the desired frequency.

The main task of the motherboard clock generator is the formation of a highly stable periodic signal for synchronizing the operation of computer elements.

The frequency of clock pulses largely determines the speed of calculations. Since a certain number of cycles is spent on any operation performed by the processor, therefore, the higher the clock frequency, the higher the performance of the processor. Naturally, this is true only for processors with the same microarchitecture, since processors with different microarchitectures may require a different number of cycles to execute the same instruction sequence.

The generated clock frequency can be increased, thereby raising the performance of the computer. But this process comes with a number of dangers. Firstly, with an increase in the clock frequency, the stability of the operation of computer components decreases, therefore, after any “overclocking” of the computer, serious testing is required to check the stability of its operation.

Also, "overclocking" can lead to damage to the elements of the computer. Moreover, the failure of the elements will most likely not be instantaneous. The service life of elements operated in conditions other than those recommended can simply be drastically reduced.

In addition to the clock generator, there are many capacitors on the motherboard to ensure a smooth flow of voltage. The fact is that the energy consumption of computer elements connected to the motherboard can change dramatically, especially when work is suspended and resumed. Capacitors smooth out such voltage surges, thereby increasing the stability and service life of all computer elements.

Perhaps these are all the main components of modern motherboards, and this review of the motherboard device can be completed.

The motherboard or system board is the foundation on which any modern computer is built, whether it be a desktop PC, laptop or embedded system.

It is the motherboard that combines components that are so different in their essence and functionality, such as a processor, RAM, expansion cards and all kinds of drives.

It is thanks to the motherboard that peripheral devices can be connected to the computer, because even if the system logic set (chipset) supports a variety of buses and interfaces, it is unlikely that anyone will be able to directly connect, for example, a printer to a conventional microcircuit.

What is a modern motherboard?
We will talk mainly about boards for desktop PCs, as the most common and close to the reader, however, a significant part of their description is applicable to boards for servers, laptops and embedded computers.

The motherboard is the main and largest printed circuit board in a computer.
In terms of the complexity of manufacturing the printed circuit board itself, the “motherboards” lag behind only the most cutting-edge graphics accelerators.

A typical motherboard is based on a four-six-layer textolite printed circuit board, while some video cards are produced on the basis of eight or even ten-layer printed circuit boards.

The use of multilayer boards allows, while maintaining standard sizes breed different electrical circuits so that their interaction is minimal.
On those layers that are deep in the board, the power and ground circuits are bred, and on the others, including the upper and lower ones, the actual signal circuits.

In order not to load the reader with specific information, we will focus on only two purely electrical parameters of the motherboard.
Since microcircuits are designed to operate in strictly specified modes, high-quality power is necessary to ensure their reliability and durability.

Of course, the power supply to which the board is connected plays a significant role here, but different components require different power, and the power consumption of individual components, for example, the processor, is not constant.

All these factors force us to resort to additional tricks.
To supply the necessary voltage to various components, all modern motherboards use a voltage regulator, which is most often installed directly on the board, but sometimes it is made in the form of a separate small board placed for proper cooling in close proximity to the power supply.

The voltage stabilizer works in automatic mode, depending on which contacts the load is applied to, in other words, to which connector a particular device or board element is connected.

The processor overclocking function, often supported by modern motherboards, uses manual voltage adjustment (within reasonable limits, of course), which is implemented for the user through the BIOS or through a specialized utility.

Capacitors are designed to deal with power surges that are detrimental to many components, capable of accumulating and then smoothly releasing charge.
It is no coincidence that there are so many capacitors on motherboards, especially around the central processor, which is characterized by sharp jumps in power consumption, depending on the load.

It is with capacitors that the decrease in the reliability of the motherboard is associated with time: they age faster than other components, in particular, due to exposure to high temperatures.

As a result, the capacitance of the capacitors drops, and they lose their ability to “take a hit” and equalize the voltage in the circuit, which negatively affects other components and, in the worst case, disables them.
So the recommendations to change the computer every three years are generated not only by marketing considerations of “moral obsolescence”, but also by quite objective reasons.

Let's move on to the direct functions of the motherboard.
AT without fail This board contains a system bus, a processor socket, slots for RAM modules (it is possible that memory chips are soldered directly into the board), expansion slots, various controllers, as well as input and output ports.

As you can see, the motherboard combines single system all computer components - without it, they would remain just a set of components that are not related to each other.

Let's turn to photography.
It shows a typical modern motherboard P5GDC-V Deluxe manufactured by the famous Taiwanese company Asus.

Based on the Intel 915G chipset, this board is designed for Intel Pentium 4 processors in the LGA 775 package and supports almost all technologies found in modern desktop computers.

Brief characteristics of this model:

Chipset 915G with integrated graphics accelerator (Northbridge) + ICH6R (Southbridge).
- Support for Pentium 4 or Celeron D processors in LGA 775 package.
- Support for DDR and DDR2 533 RAM up to 4 GB.
- Support for PCI Express x16 and x1 bus.
- PCI bus support.
- Support for high-speed USB 2.0 and IEEE 1394 (FireWire) interfaces.
- IDE and Serial ATA controllers.
- Gigabit network controller.
- Eight-channel (7.1) sound controller.
- ATX form factor (dimensions - 305 x 244 mm).

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Motherboards are a miracle of modern technology and are the main component of a computer. Looking at any motherboard, you can see many different tracks, transistors and capacitors, connectors, and more. All this is placed on the so-called textolite (the material from which motherboards are made). This article will describe the main components of motherboards.

What role do motherboards play in a computer, and why are they needed?

In fact, no computer can work without a motherboard (system) board. It is on it that all the connectors and slots for connecting various computer devices are located. For example, it has connectors for video cards, for a processor, RAM, and for many other devices that ensure the operation of a computer. Naturally, any of these devices needs voltage, because without electric current they won't be able to work. Especially for this, a power supply is connected to the motherboard. Further, the motherboard itself distributes power between all devices. Devices that are located separately from it are also connected to the system board. For example, or , are located in front of the computer and are connected to the motherboard with special multi-channel cables. Tracks, of which you can find a huge number on the motherboard, are designed to transfer information between all connected devices.

If you insert a Flash drive containing a movie into the USB connector and want the movie to be on your computer, then by controlling the mouse, you can transfer data from your drive to the computer's built-in hard drive. The moment of data transfer can be monitored on the monitor screen. After the movie is successfully transferred to the hard drive, you can safely turn it on through the video player and enjoy watching it. All the rest of the work will be done by the video and audio adapter, which will display the video film and, accordingly, play the sound of the film in the speaker system. The system board will also actively participate in these processes.

What are motherboards made from?

Motherboards are made of multilayer textolite, on which tracks for data exchange, various capacitors and transistors are located. The tracks are located on many layers of the motherboard, and special holes are made in the layers to connect them. For example, an audio adapter located on the top layer can communicate with the contact chain of other layers. Currently, modern boards can contain up to 10 layers.

Who makes motherboards?

When buying a motherboard, you can find them from 11 different manufacturers. The leaders in the production of motherboards at the moment are the following companies: Gigabyte, ASUS, MSI and Foxconn. You can also find motherboards from the largest processor manufacturer - Intel, while its main rival AMD does not manufacture motherboards.

Can any motherboard be inserted into any computer?

Far from every computer, you can insert a certain motherboard, because they may differ in size. At the moment, the most popular are ATX (motherboard dimensions: 305x244 mm), micro ATX (244x244mm), mini ATX (171x171mm). Depending on the size of the motherboard, it may have more expansion slots and an improved cooling system.

Main components of the motherboard

CPU socket

Any motherboard will contain several components. One of these components will be the socket for the processor. In the world market, two leading processor manufacturing companies are now fighting "for a place in the sun" - these are Intel and AMD. When choosing a processor, you must know which socket for it is located on your motherboard. For example, for the second generation processors from Intel - Sandy Bridge, boards with an LGA 1155 connector are produced, i.e. this processor cannot be inserted into other sockets. AMD offers backward compatible processors (but not all). For example, a processor with an AM3 socket can be inserted into an AM2 socket, and vice versa.

Chipsets

Chipsets are one of the main components of the motherboard. It is they who organize the exchange of data between all computer devices. It is worth knowing that not every chipset can use the components built into the processor. For example, Sandy Bridge processors that are compatible with the P67 and Z68 chipsets have a built-in graphics chip, but only Z68s can work with the graphics chip. The P67 chipset for displaying images on a monitor will require the installation of a separate video card.

Chipsets include two: north and south bridges. Both of them are on the system board, but communicate different devices. Thus, the northbridge is responsible for the exchange of data between the processor, RAM, memory controller and video card. In turn, the south bridge monitored the exchange of data between various devices I/O and disks. With the development of technology, in modern systems, the tasks of the north bridge began to slowly move to the central processor, which, according to the developers, should affect the increase in system performance.

Graphics adapter

Previously, on many ASUS and MSI motherboards, a discrete video adapter was soldered in, which was responsible for displaying the image on the monitor. This technology can be found today, but it is outdated. Now video adapters are either built into the processor or installed separately using expansion slots. A graphics adapter is required for normal operation of the computer.

Expansion slots

On any motherboard, it will not be difficult to find expansion slots. At the moment, expansion slots on the PCI express bus are considered the most popular and fastest. These connectors are designed to connect video cards, audio cards, network cards, etc. to the motherboard.

BIOS and its battery

The microcircuit responsible for the operation of the motherboard, and for the performance of all connected devices, contains a set of commands to check all devices and the motherboard. The BIOS is built into many motherboards. The BIOS chip is powered by a special small round battery, which is also easy to find on the motherboard. When the computer is turned off, the BIOS will store all information about the system, such as date and time. In the latest models, the BIOS chip can be replaced by . This chip is the receiver of the BIOS, and performs the same functions, but the main difference from the BIOS will be the presence of a graphical interface and the ability to control with the mouse, and the presence of more functions.

Slots for RAM

All motherboards have slots for RAM. As a rule, these are long narrow slots located next to each other. Their number is usually from 2 to 4, but sometimes more.

Power connector and fan connector

All motherboards are powered by a power supply that converts normal voltage on the network to the correct voltage for the computer. It is connected via a special connector to the motherboard. There are also several connectors on the motherboard for connecting the cooling system, which is presented in the form of fans. The fan is located in the cover of the system unit, on the processor and are on chipsets and protect the system from overheating.

Connectors for connecting peripherals

On the back of the motherboard there are several connectors to which external devices are connected. As a rule, here you can connect a monitor, printer or scanner, mouse and keyboard, audio speakers and much more.

How are motherboards divided into price categories?

The price of the motherboard primarily depends on the number of connectors and interfaces. There are several categories of motherboards on which its cost depends: basic, standard, high-performance and professional. Basic (price up to 2000 rubles) is usually used in offices where a small number of connectors is enough just for work. Standard and high-performance (from 2000 to 4000 rubles, and more than 4000 rubles) are the most popular boards. Most often used at home and well suited for games. Professional boards and motherboards for enthusiasts (from 7000 rubles) are full of new Bluetooth, WLAN modules and other interesting technical features. Most often used to work with graphics and for other purposes, when you need a larger number of expansion cards.

How can I determine the type of motherboard installed?

by the most in a simple way To find out which motherboard is installed in your PC, download the CPU-Z program. This program will not only help you determine the type of board, but also give useful information about the system. Always the most detailed information about the motherboard can be found in the manual offered for it or on the manufacturer's website.