What is the name of the device for interconnecting a computer with other computers? Well, if this question is spinning in your head, then you are doing the right thing by reading this article. So, a device for interconnecting one computer with others is an adapter (in other words, What is it? How does it work? What functions does it perform? All these questions can be answered within the framework of this article.

What is an adapter

This is what they call a device that directly works with the data transmission medium. Thanks to it, connections with other computers are established directly or using something else.

This device solves the problem of ensuring the reliability of the exchange of binary data, which is presented in the form of corresponding electromagnetic signals. Their transmission is carried out using external communication lines. Since the adapter is a computer controller, it operates under the control of the appropriate driver for the operating system used. The separation of functions between them may vary depending on the implementation.

Adapter development

So, we already know that a device for interconnecting one computer with others is an adapter. Now let's take a quick look at how this technology developed.

In the first local area networks, adapters, together with a segment of coaxial cable, carried the entire range of communications equipment. Thanks to them, the interaction of computers was organized. Then direct interaction between various electronic computers was used.

This technology is still used, but most modern standards also provide for a number of special communication devices (for example, a bridge, switch, hub or router). They take over some of the functions regarding data flow control.

Wrong Assumptions

You can often hear or read that the device for interconnecting one computer with others is a processor. Know that this is not true. A device for interconnecting one computer with others is called an adapter or network card, but nothing else! It is not known for certain where this misconception came from, but if someone is mistaken, it would be better to correct him.

Data formatting and coding functions

The functions of the adapter are that information must be transmitted in the form of a frame having a certain format. In this case, coding is understood as the presentation of information using certain signals in such a way that they can be received on the other side, but the meaning contained in them should not be lost.

Let's take a closer look at this. The frame includes several service fields. These include the address of the computer to which the data needs to be transferred and each frame. It will be used to draw a conclusion about the correctness of the information provided. About coding we can say that its meaning is to overcome interference and provide the receiving equipment with the ability to recognize the received data.

There are also some technical nuances. Thus, when using broadband cables in a local network, adapters do not use signal modulation. Since this is only necessary when transmission occurs over narrowband communication lines (voice-frequency telephone channels can be used as such).

Access function

The following function is used when interacting with the data translation environment. It is used in cases where it is necessary to gain access using a specific algorithm.

This is necessary due to the operation of a shared data translation environment. But there is a tendency to abandon this approach in favor of individual communication channels between computers and network communication devices (similar to what is done in wired telephony).

Conversion and synchronization function

Conversion and synchronization are necessary to provide data in a readable form. Thus, thanks to the adapter, information can be converted from serial form to parallel form and vice versa. This is necessary because to simplify the synchronization task (and also to reduce the cost of communication lines), data is transmitted gradually - one bit after another. For comparison, in a computer information is moved byte by byte.

Regarding synchronization, we can say that it is necessary to maintain constant conflict-free interaction between the receiver and the data transmitter. The adapter successfully solves this problem thanks to special coding methods that do not use an additional bus with clock signals.

Thanks to this method, periodic changes in the state of the signal that is transmitted are easily ensured. In addition to problems with synchronization at the bit level, the adapter solves similar problems with relative bytes and frames.

Technical features

Adapters are distinguished by the internal data bus and the technology used. So, if we talk about the first case, then there may be the following types:

• EISA;

With network technologies, not everything is so simple. Usually one adapter supports one of them. But despite this, information is transmitted without problems. This is achieved due to the fact that different data transmission media are used. For example, one of the most popular technologies - Ethernet - can easily support coaxial and fiber optic cables or unshielded twisted pair.

If only one medium can be supported by the adapter, then converters and transceivers are used. What are these devices?

Transceivers and converters

Transceivers are also called transceivers. They are part of the network adapter and represent its terminal device that connects to the cable. Although, it should be noted that initially they were located on cables (if we consider the first Ethernet standard), but then it was decided that it would be more convenient to place them on the adapter.

Instead of a transceiver, you can use a converter. He deals with the coordination of information when using various data transmission media. An example is a local home network that uses a twisted pair cable with a coaxial cable.

Conclusion

Well, the task is completed - the terminology and features of the adapters are explained. Now there should be no questions about what the device for interconnecting one computer with other computers is called. In addition, we looked at what functions are performed by adapters, what development path they have taken, and also how they can be improved without fundamental changes. The information provided is not enough for an in-depth study of the topic, but as a start to studying the construction of physical data transmission, it will be useful to you.

Design and purpose of the motherboard

A motherboard or system board is a multilayer printed circuit board that is the basis of a computer, determining its architecture, performance and communicating between all elements connected to it and coordinating their work.

1. Introduction.

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

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

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 a processor. Determines which type of processors can be connected to the motherboard. 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, you have to change not only the processor, but also the motherboard with all the ensuing consequences.

- central processor - the main device of the computer, which performs mathematical, logical operations and control operations of all other elements of the computer;

RAM (Random Access Memory) controller. Previously, the RAM controller was built into the chipset, but now most processors have a built-in RAM controller, which increases overall performance and relieves the load on the chipset.

RAM is a set of chips for temporary storage of data. Modern motherboards have the ability to connect several RAM chips at the same time, usually four or more.

PROM (BIOS), containing software that tests the main components of the computer and configures the motherboard. And CMOS memory storing BIOS settings. Often, several CMOS memory chips are installed to quickly restore the computer's functionality 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 is determined by the type of motherboard used. If necessary, additional I/O controllers can be installed in the form of expansion cards;

A quartz oscillator that produces signals that synchronize the operation of all computer elements;

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 original voltage into the required voltage to power the components installed on the motherboard;

Monitoring tools that measure fan rotation speed, temperature of main computer elements, 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 to provide better sound, but in most cases this is not required;

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

Buses are conductors for exchanging signals between computer components.

2. Printed circuit board.

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

As a result, malfunctions may occur even in highly 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, greatly increasing 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 planes.

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

The layout and length of the tracks is extremely important for the normal operation of all computer components, therefore, when choosing a motherboard, special attention must 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 operating parameters. For example, overclocking the processor or memory.

The printed circuit board contains all the components of the motherboard and connectors for connecting expansion cards and peripheral devices. The figure below shows a block diagram of the arrangement 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.

The chipset or system logic set is the main set of chips on the motherboard that ensures the joint functioning 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 controllers, and so on.

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

However, recently there has been a tendency to combine the north and south bridges into a single component, as the memory controller is increasingly being built directly into the processor, thereby relieving the north bridge, and faster and faster communication channels with peripheral devices and expansion cards are appearing. And the technology for producing integrated circuits is also developing, making them smaller, cheaper and consuming less energy.

Combining the north and south bridges into one chipset allows you to increase system performance by reducing the time of interaction with peripheral devices and internal components previously connected to the south bridge, but it 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 based on a chipset divided into two components. These components are called the North and South Bridge.

The names Northern and Southern 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 chipsets based on the functions they perform: they serve to connect various buses and interfaces.

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

1. Differences in speed modes.

Northbridge works with the fastest and most bandwidth-hungry components. These components include the video card and memory. However, today most processors have a built-in memory controller, and many have a built-in graphics system, which, although much inferior to discrete video cards, is still often used in budget personal computers, laptops and netbooks. Therefore, every year the load on the north bridge decreases, which reduces the need to divide the chipset into two parts.

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

Standards for communication buses with memory, video cards and processors change much less frequently than standards for communication with expansion cards and peripheral devices. This allows, in case of changing the communication interface with peripheral devices or developing a new communication channel, not to change the entire chipset, but to replace only the south bridge. In addition, the north bridge works with faster devices and is more complex than the south bridge, since the overall performance of the system largely depends on its operation. Therefore, changing it is expensive and difficult 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 North Bridge, as its name suggests, performs the functions of controlling and directing the data flow from 4 buses:

1. Communication buses with the processor or system bus.
2. Memory buses.
3. Communication buses with the graphics adapter.
4. Communication buses with the south bridge.

The north bridge is designed in accordance with the functions performed. It consists of a system bus interface, a communication bus interface with the south bridge, a memory controller, and a communication bus interface with the graphics card.

At the moment, most processors have a built-in memory controller, so the memory controller function for the northbridge can be considered obsolete. And given that there are many types of RAM, we will highlight 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 the 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 south bridge, set priorities and create a queue, if necessary. Moreover, it must be so balanced as to reduce downtime as much as possible when computer components try to access certain resources.

Let's take a closer look at the existing communication interfaces with the processor, graphics adapter and south bridge.

3.1.1. Interfaces for communication with the processor.

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

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

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

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

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

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, throughput increased from 400 Mbit/s to 12800 Mbit/s.

The FSB bus 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, for exchange in each direction its own communication line is allocated. In addition, it works using DDR (Double Data Rate) technology, transmitting data both on the rise and 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 for exchange at a speed of 800 MT/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 greater 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 it to be used not only for connecting the processor with the northbridge and RAM, but also in slow devices. At the same time, the possibility of reducing the bit capacity and frequency leads to energy savings.

The minimum bus clock frequency is 200 MHz, while data will be transferred at a speed of 400 MTr/s, due to DDR technology, and the minimum bit width is 2 bits. With minimum parameters, 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 the HyperTransport v 3.1 revision.

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

To communicate between the processor and the chipset, 4 DMI channels are usually used, 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. Budget mobile systems can use a bus with two DMI channels, which reduces the throughput by half compared to the 4-channel option.

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

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

We briefly reviewed the main interfaces for connecting the processor to the chipset. Next, we will look at the interfaces for connecting the North Bridge to the graphics adapter.

3.1.2. Interfaces for communication with the graphics adapter.

At first, the common ICA, VLB, and then PCI bus were used to communicate with the graphics processor, 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 required enormous power for calculations 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 operating modes: with DMA (Direct Memory Access) memory and DME (Direct in Memory Execute) memory.

In DMA mode, the main memory was considered to be the memory built into the video adapter, and in DME mode, it was 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 mode of working with DME memory is called AGP texturing.

However, very soon the bandwidth of the AGP bus was no longer enough to operate in DME mode, and manufacturers began to increase the volume of built-in memory. Soon, increasing the built-in memory stopped helping and the bandwidth of the AGP bus became absolutely insufficient.

The first version of the AGP bus, AGP 1x, operated at a clock frequency of 66 MHz and had a maximum data transfer speed of 266 MB/s, which was not enough for full 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 improved and a mode of data transmission on the edge and fall of the clock pulse was introduced, 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 on the market supported AGP 1x and AGP 2x operating modes.

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

At the same time, the reference bus clock frequency did not change and remained equal to 66 MHz, and to make it possible to transmit four blocks of data in one clock cycle, an additional signal was introduced that runs synchronously with the reference clock frequency, but with a frequency of 133 MHz. Data was transmitted on 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 video cards of AGP 2.0 and subsequent revisions of the AGP bus.

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

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

PCI express is a point-to-point serial bidirectional bus developed in 2002 by the non-profit group PCI-SIG, which included companies 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 throughput of one channel is 400 MB/s, since for every 8 bits of data transferred there are 2 service bits and the bus is bidirectional, that is, exchanges in both directions occur simultaneously. The bus typically uses several channels: 1, 2, 4, 8, 16 or 32, depending on the required bandwidth. Thus, buses based on PCI express in the general case are a set of independent serial data transfer channels.

So, when using the PCI express bus, a 16-channel bus is usually used to communicate with video cards, and a single-channel bus is used to communicate 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 increased by 2 times. 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 throughput was increased by 2 times, and the maximum number of transactions increased from 5 to 8 billion, and the maximum throughput increased by 2 times, thanks to a change in the principle of information encoding, in which every 129 bits of data there are only 2 service bits, 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 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 planned for 2012.

It is worth noting that at the moment the throughput 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 provide a significant increase in performance in the processor-video card combination. But, as they say, wait and see.

In the near future, it is planned to release a revision of PCI express 4.0, in which the speed will be increased by another 2 times.

Recently, there has been a tendency to integrate 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 ensure interaction with expansion cards and peripheral devices.

This concludes the review of communication interfaces between the north bridge and the video adapter and moves on to a review of the communication interfaces between the north bridge and the south bridge.

3.1.3. Communication interfaces with the south bridge.

For quite a long time, the PCI bus was used to connect the north bridge to 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 bridge. However, as the performance of expansion boards increased, its bandwidth became insufficient. It was supplanted by more powerful buses initially from the tasks of connecting the north and south bridges, and in recent years they began to use a faster bus - PCI express - for communication with expansion cards.

The main technical characteristics of the PCI bus are as follows:

Audit	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	5/3.3 V	5/3.3 V	5/3.3 V
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 the main revisions, but since at the moment the PCI interface is practically replaced by faster buses, I will not describe in detail the characteristics of all revisions.

When using the bus to connect the north and south bridges, 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 along with expansion cards. The bandwidth of the bus was divided between all devices connected to it, and, therefore, the declared peak throughput 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’s bandwidth began to be enough, and for communication between the north and south bridges they began to use buses such as: hub link, DMI, HyperTransport, 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– 8-bit point-to-point bus developed by Intel. The bus operates at a frequency of 66 MHz and transmits 4 bytes per clock cycle, which allows for maximum throughput of 266 MB/sec.

The introduction of the hublink bus changed the motherboard architecture and relieved the PCI bus. The PCI bus was used only for communication with peripheral devices and expansion cards, and the hublink bus was used only for communication with the northbridge.

The throughput of the hublink bus was comparable to that of the PCI bus, but since it did not have to share the channel with other devices, and the PCI bus was offloaded, the throughput was quite sufficient. But computing technology does not stand still, and the hublink bus is currently practically not used due to insufficient performance. It has been supplanted by tires 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 bridge, but most of them are already hopelessly outdated or rarely used, so we will not focus on them. This concludes the overview of the main functions and design of the north bridge and moves on to the south bridge.

3.2. Main functions of the South Bridge.

The South Bridge is responsible for organizing interaction with slow computer components: expansion cards, peripheral devices, input/output devices, inter-machine communication channels, and so on.

That is, the South Bridge relays data and requests from devices connected to it to the North Bridge, which transmits them to the processor or RAM, and receives processor commands and data from RAM from the North Bridge, and relays them to the devices connected to it.

The south bridge includes:

Communication bus controller with north bridge (PCI, hublink, DMI, HyperTransport, etc.);

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

Controller for 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 peripheral device controllers built into it.

We have already considered the communication interfaces between the north bridge and the south bridge. Therefore, let's immediately move on to communication interfaces with expansion cards.

3.2.1. Communication interfaces with expansion cards.

At the moment, the main interfaces for exchange with expansion cards are PCI and PCIexpress. However, the PCI interface is being actively replaced, and in the next few years it will practically become 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 it. Let's move straight 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 peripheral devices and other computers, the most common of which 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 give a brief 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 south bridge of the motherboard. Modern motherboards can accommodate up to 12 USB channel controllers with two ports each.

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

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

The USB interface has built-in power lines, which allows you to use devices without their own power source or simultaneously recharge the batteries of end devices, such as phones, while exchanging data.

However, if a multiplier (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 pin than the signal pins. Therefore, when connecting a 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 signal conductors does not result in a voltage surge.

At the moment, there are three main revisions of the USB interface (1.0, 2.0 and 3.0). Moreover, they are compatible from the bottom up, that is, devices intended for revision 1.0 will work with the interface of revision 2.0, respectively, devices intended for USB 2.0 will work with USB 3.0, but devices for USB 3.0 most likely will not work with USB 2.0 interface.

Let's look at 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 revision of USB 1.1 was the first to become widespread.

The technical characteristics of revisions 1.0 and 1.1 are as follows:

Data transfer speed – up to 12 Mbit/s (Full-Speed ​​mode) or 1.5 Mbit/s (Low-Speed ​​mode);

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

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

The technical characteristics of revision 2.0 are as follows:

Data transfer speed – up to 480 Mbit/s (Hi-speed), up to 12 Mbit/s (Full-Speed ​​mode) or up to 1.5 Mbit/s (Low-Speed ​​mode);

Synchronous data transfer (on request);

Half-duplex exchange (transfer is possible in only one direction at a time);

The maximum cable length is 5 meters;

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

It is possible to connect devices operating in modes with different bandwidths 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 grounding braid.

USB 3.0 – revision released in November 2008. In the new revision, the speed was increased by an order of magnitude, to 4800 Mbit/s, and the current strength was almost doubled, to 900 mA. At the same time, the appearance of connectors and cables has changed greatly, but upward compatibility remains. Those. Devices running USB 2.0 will be able to connect to the 3.0 connector and will work.

The technical characteristics of revision 3.0 are as follows:

Data transfer speed – up to 4800 Mbit/s (SuperSpeed ​​mode), up to 480 Mbit/s (Hi-speed mode), up to 12 Mbit/s (Full-Speed ​​mode) or up to 1.5 Mbit/s (Low-Speed ​​mode) );

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

Asynchronous data transfer;

Duplex exchange in SuperSpeed ​​mode (simultaneously transmitting and receiving data is possible) and simplex in other modes.

The maximum cable length is 3 meters;

The maximum number of connected devices 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 data reception, and two - for transmission in SuperSpeed ​​mode, and two grounding braids: one for data transmission cables in Low-Speed/Full-Speed/High-Speed ​​mode, and one for cables used in SuperSpeed ​​mode.

IEEE 1394 (Institute of Electrical and Electronic Engineers)– a high-speed serial bus standard adopted in 1995. Different companies call tires designed to this standard differently. Apple has FireWire, Sony has i.LINK, Yamaha has mLAN, Texas Instruments has Lynx, Creative has SB1394, and so on. This often leads to confusion, but despite the different names, they are the same tire operating to the same standard.

This bus is designed to connect high-speed peripheral devices such as external hard drives, digital video cameras, music synthesizers, and so on.

The main technical characteristics of the tire are as follows:

The maximum data transfer rate varies from 400 Mbit/s, for revision IEEE 1394, to 3.2 Gbit/s, for revision IEEE 1394b;

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. You cannot connect more devices because in the IEEE 1394 standard, each device has a 16-bit address;

Possibility of connecting several computers into a network;

Hot plugging and unplugging of devices;

Ability to use bus-powered devices that do not have their own power source. In this case, the maximum current is up to 1.5 Amperes, and the voltage is from 8 to 40 Volts.

Ethernet is a standard for building computer networks based on packet data transmission technology, developed in 1973 by Robert Metclough of Xerox PARC Corporation.

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

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

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

Gigabit Ethernet provides data transfer speeds up to 1 Gbit/s. 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 transmit large volumes of information, there are ten, forty and one hundred gigabit Ethernet standards 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 devoted to 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 simultaneously.

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 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, Wi-Fi throughput is as follows:

Revision of the standard	Clock frequency	Claimed maximum power	Average data transfer speed in practice	Communication range indoors/outdoors
802.11a	5 GHz	54 Mbit/s	18.4 Mbit/s	35/120 m
802.11b	2.4 GHz	11 Mbit/s	3.2 Mbit/s	38/140 m
802.11g	2.4 GHz	54 Mbit/s	15.2 Mbit/s	38/140 m
802.11n	2.4 or 5 GHz	600 Mbit/s	59.2 Mbit/s	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 cards. Therefore, we will consider these interfaces, along with those described above, in an article devoted to machine-to-machine communication, and now we will move on to a description of the communication interfaces of the south bridge with hard drives.

3.2.3. Interfaces of south bridge communication buses with hard drives.

Initially, the ATA interface was used to communicate with hard drives, but later it was replaced by more convenient and modern SATA and SCSI interfaces. Here is 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 was later renamed ATA, and with the advent of the SATA interface in 2003, PATA was renamed PATA.

Using the PATA interface means that the hard drive controller is not located on the motherboard or in the form of an expansion card, but is built into the hard drive 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 cable is 46 cm. Two devices can be connected to one cable, and one of them must be a master and the other a 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 throughput is much lower than the stated theoretical throughput, due to the overhead of organizing the exchange protocol and other delays. In addition, if two hard drives are connected to the bus, the bandwidth will be divided between them.

In 2003, the PATA interface was replaced by the SATA interface.

SATA (Serial ATA)– serial interface for communication between the south bridge and 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 though the total number of cables increases compared to the PATA interface, since each drive is connected with two cables, the free space inside the system unit becomes significantly larger. 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 parameters of revisions.

The SCSI interface stands apart from these interfaces.

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 throughput, but is complex and expensive. Therefore, it is mainly used in servers and industrial computing systems.

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

Interface revision	Bit depth	Data transmission frequency	Max. throughput	Cable length (m)	Max. number of devices	Released
SCSI-1	8 bit	5 MHz	40 Mbit/s	6	8	1986
SCSI-2	8 bit	10 MHz	80 Mbit/s	3	8	1989
SCSI-3	8 bit	20 MHz	160 Mbit/s	3	8	1992
Ultra-2 SCSI	8 bit	40 MHz	320 Mbit/s	12	8	1997
Ultra-3 SCSI	16 bit	80 MHz	1.25 Gbit/s	12	16	1999
Ultra-320 SCSI	16 bit	160 MHz	2.5 Gbit/s	12	16	2001
Ultra-640 SCSI	16 bit	320 MHz	5 Gbit/s	12	16	2003

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

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

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

As a result, it is easier to abandon a parallel interface in favor of a serial one with a higher clock frequency. If necessary, several serial communication lines can be used, located further apart and protected by braided shielding. This is what they did when moving from the parallel PCI bus to the serial PCI express, from PATA to SATA. The SCSI bus followed the same development path. This is how the SAS interface appeared in 2004.

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

In 2012, it is planned to release a revision of SAS 3, with a throughput of 12 Gbit/s, but devices supporting this revision will not begin to appear en masse until 2014.

Also, do not forget that the SCSI bus was common, 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.

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

3.2.4. Communication interfaces with slow motherboard components.

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

The ISA (Industry Standard Architecture) bus is a 16-bit bus developed in 1981. ISA operated 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 transmission frequency of 10 MHz and a bandwidth of up to 40 Mbit/s. 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 still in use today. The bus operates at a clock frequency of 33.3 MHz, which provides a throughput of 16.67 Mbit/s.

The bus bandwidth is quite small, but it is quite sufficient for communication with slow components of the motherboard. 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) is a program flashed into read-only memory (ROM). In our case, the ROM is built into the motherboard, but its own version of BIOS is present in almost all elements of the computer (video card, network card, disk controllers, etc.), and indeed in almost all electronic equipment (both printers and in a video camera, and in a modem, etc.).

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

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

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

Users can manage most BIOS settings and even update it.

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

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

In this menu, you can set the system time, operating parameters of floppy drives and hard drives, increase (or decrease) the clock frequency of the processor, memory and system bus, communication buses, and configure other computer operating parameters. However, you should be extremely careful here, since incorrectly set parameters can lead to operational errors or even damage the computer.

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

5. Other elements of the motherboard.

In addition to the elements described above, the motherboard contains a clock generator, consisting of a quartz resonator and a clock generator. The clock generator consists of two parts, since the quartz resonator is not capable of generating pulses at the frequency required by 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 obtaining the required frequency.

The main task of the motherboard clock generator is to generate a highly stable periodic signal to synchronize the operation of computer elements.

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

The generated clock frequency can be increased, thereby increasing the performance of the computer. But this process is fraught with a number of dangers. Firstly, when the clock frequency increases, the stability of the 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 computer components. Moreover, the failure of the elements will most likely not be instantaneous. The service life of elements operated in conditions other than recommended may simply be sharply reduced.

In addition to the clock generator, there are many capacitors on the motherboard that ensure smooth voltage flow. 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 is where we can finish the review of the motherboard design.

PC architecture. Backbone-modular construction principle, 244.23kb.

Test “Basic ICT devices” Option 1 Which line lists the minimum set, 31.4kb.

Approximate outline of the abstract The purpose of the device and the principle of its construction Structural, 15.15kb.

General purpose programs for solving medical problems. History of the development of computing tools, 59.78kb.

1. pu. Classification. Purpose, 1046.98kb.

Topic: "The main devices of a computer, their functions and interconnection during operation. Backbone - modular principle of constructing a PC."

The purpose of the lesson: Explain to students the general principle of organizing the storage of information in computer memory and the exchange of information between computer devices, as well as the software principle of computer operation.

1. Internal computer architecture.

Personal computers - These are universal devices for storing, processing and transmitting information.

Computer architecture- it is a general description of the structure and functions of a computer. Architecture does not describe the details of the technical and physical devices of a computer.

Main components of computer architecture:

• CPU,
• internal (main) memory,
• external memory,
• input devices, output devices.

The most popular type of computer in our time is the personal computer (PC). A PC is a small-sized computer designed for individual user work, equipped with user-friendly (friendly) software.

Almost all models of modern PCs have backbone type of architecture(including the world's most common IBM PC and Apple Macintosh).

Diagram of the device of computers built on the backbone principle.

Processor Internal memory

Peripherals

Computer memory

PC memory is divided into internal and external.

Inner memory A PC includes a random access memory (RAM) and a read-only memory (ROM).

RAM-fast, semiconductor, volatile memory. RAM stores the currently executing program and the data with which it directly works. This means that when you run any computer program located on the disk, it is copied into the RAM, after which the processor begins to execute the commands set out in this program. A piece of RAM called “video memory”, contains data corresponding to the current image on the screen. When the power is turned off, the contents of the RAM are erased. Computer performance (working speed) directly depends on the size of its RAM, which in modern

on computers it can reach up to 4 GB. In the first computer models, RAM was no more than 1 MB. Modern application programs often require at least 4 MB of RAM to run; otherwise they simply don't run.

RAM is memory used for both reading and writing information. When the power is turned off, the information in RAM disappears (volatility).

ROM- fast, non-volatile memory. ROM is read-only memory. Information is entered into it once (usually at the factory) and stored permanently (when the computer is turned on and off). ROM stores information that is constantly needed on the computer.

The ROM contains:

• test programs that check the correct operation of its units every time you turn on the computer;
• programs for controlling basic peripheral devices - disk drive, monitor, keyboard;
• information about where the operating system is located on the disk.

Main memory consists of registers. Register is a device for temporarily storing information in digitized (binary) form. The storage element in the register is trigger- a device that can be in one of two states, one of which corresponds to storing a binary zero, the other to storing a binary one. The trigger is a tiny capacitor battery that can be charged many times. If such a capacitor is charged, it seems to remember the value “1”; if there is no charge, the value “O”. The register contains several triggers related to each other. The number of flip-flops in a register is called computer bit capacity. Computer performance is directly related to the bit depth, which can be 8, 16, 32 and 64.

CPU

CPU - the central device of the computer.

Processor purpose:

1. control the operation of the computer according to a given program;
2. perform information processing operations.

A microcircuit that implements the functions of the central processor of a personal computer is called microprocessor. Often the name of a computer is associated with the type of processor, for example “Pentium”.

The microprocessor is designed as a very large integrated circuit. The term “large” does not refer to the size, but to the number of electronic components placed on a small silicon wafer. Their number reaches several million. The more components a microprocessor contains, the higher the computer's performance. The size of the minimum microprocessor element is 100 times smaller than the diameter of a human hair. The microprocessor is inserted with pins into a special socket on the system board, which has the shape of a square with several rows of holes around the perimeter.

The capabilities of a computer as a universal performer for working with information are determined by the processor command system. This command system is a machine command language (MCL). Computer control programs are compiled from NMC commands. A separate command defines a separate operation (action) of the computer. In NMC, there are commands that perform arithmetic and logical operations, operations for controlling the sequence of command execution, operations for transferring data from one memory device to another, etc.

Processor composition:

• control device (CU),
• arithmetic logic unit (ALU),
• processor memory registers.

The control unit controls the operation of all computer devices according to a given program. (The function of a control device can be compared to the work of a conductor who controls an orchestra. A program is a kind of “score” for the control unit.)

ALU - processor computing instrument; This device performs arithmetic and logical operations on program commands.

Registers are the internal memory of the processor. Each of the registers serves as a kind of draft, using which the processor performs calculations and stores intermediate results of the program.

The most important characteristic of the processor is clock frequency- the number of operations performed by it in 1 second (Hz). The 8086 processor, manufactured by Intel for IBM personal computers, could perform no more than 10 million operations per second, i.e. its frequency was 10 MHz. The clock frequency of the 80386 processor was already 33 MHz, and a modern Pentium processor performs an average of 100 million operations per second.

Besides, Each specific processor can work without more than a certain amount of RAM. For the 8086 processor this amount was only 1 MB, for the 80286 processor it increased to 16 MB, and for the Pentium it is 1 GB. By the way, a computer, as a rule, has a much smaller amount of RAM than the maximum possible for its processor.

The processor and main memory are located on a large board called maternal. To connect various additional devices (disk drives, manipulators such as mice, printers, etc.) to it, special boards are used - controllers. They are inserted into the connectors (slots) on the motherboard, and towards their end (port), exiting the computer, an additional device is connected.

Examples of microprocessor characteristics:

1. MP Intel-80386: address space -232 bytes = 4 GB, 32 bits, clock frequency - from 25 to 40 MHz
2. MP Pentium: address space - 232 bytes = 4 GB, bit capacity - 64 TB, clock frequency - from 60 to 100 MHz.

Information communication between computer devices is carried out throughinformation highway (another name is common bus).

Highway - This is a cable consisting of many wires.

One group of wires (data bus) carries the information being processed, and another (address bus) carries the addresses of memory or external devices accessed by the processor. There is also a third part of the highway - the control bus, through which control signals are transmitted (for example, a signal that the device is ready for operation, a signal for the device to start operating, etc.).

The number of bits simultaneously transmitted on the bus is called bus width. Any information transmitted from the processor to other devices via the data bus is accompanied by an address transmitted via the address bus (just as a letter is accompanied by an address on an envelope). This can be the address of a cell in RAM or the address (number) of a peripheral device.

In a modern PC it is implemented open architecture principle . This principle allows you to change the composition of PC devices (modules). Additional peripheral devices can be connected to the information highway, and some device models can be replaced by others. It is possible to increase the internal memory or replace the microprocessor with a more advanced one. The hardware connection of the peripheral device to the backbone is carried out through a special block - controller (another name is adapter). Software control of the device operation is carried out through the program - driver. which is a component of the operating system. Therefore, to connect a new peripheral device, the computer must use the appropriate controller and install the appropriate driver in the OS.

Key Peripherals

Peripherals- These are devices with the help of which information is either entered into a computer or output from it. They are also called external or data input/output devices. Conventionally, they can be divided into basic ones, without which the computer is practically impossible to operate, and others, which are connected if necessary. The main devices include the keyboard, monitor and disk drive.

Keyboard serves to enter text information. There is a microcircuit inside it - encoder,- which converts the signal from a specific key into a binary code corresponding to a given character.

Monitor (display) depending on the specific program it works in one of two modes - text or graphic. In text mode, the screen consists of separate sections - acquaintance One character can be output to each familiar location. In the video memory area at this moment there is data characterizing each familiar location - character color, background color, brightness, etc. In graphic mode, the screen consists of individual dots - pixels. The data in video memory characterizes the color of a specific pixel - this is how an image is created. The number of pixels that make up a monitor screen is called monitor resolution. The characteristics of currently common monitors are shown in the table:

Monitor	Text mode	Graphics mode
C.G.A.	80x25, 16 colors	640x200, 2 colors; 20x200, 4 colors
E.G.A.	80x25 16 colors; 80x43, 16 colors	640x350, 16 colors
VGA	80x25, 16 colors; 80x50, 16 colors	640x480, 16 colors
SVGA	80x50, 16 colors	640x480, 256 colors; 800x600, 16 colors

Drive. Discs

To save information, it is recorded on special hard and flexible magnetic disks. Recording is based on the ability of certain materials containing iron to be stored on the ring-shaped tracks of a disk in the form of two differently magnetized sections. Tracks consist of separate parts - sectors of 512 bytes. Tracks and sectors are numbered.

Magnetic disk drive (disk drive) consists of a motor that rotates the disk and a special reading and writing magnetic head.

Hard magnetic disk (hard drive) located inside the computer. The hard drive capacity can range from 10 MB to 1 GB (and this is not the limit). A computer may have a package of (several) hard drives.

Flexible magnetic disks (floppy disks) There are two types: 3-inch (3.5" - 8 mm) and 5-inch (5.25" - 133 mm). The type is determined by the diameter of the disk located inside the plastic box. The plastic box itself serves as protection against external influences. The volume of a floppy disk depends on the recording density on the track, which can be single (SD - Single Density), double (DD - Double Density), quadruple (QD - Quadrupty Density) and high (HD - High Density), as well as on the number of working sides on floppy disk (Single Sided - SS and Double Sided - DS). The maximum capacity of a floppy disk is usually indicated in its labeling. The following table shows the currently most commonly used types of floppy disks:

	3-inch		5 inch
Floppy disks	DS/DD	DS/HD	DS/DD	DS/HD
Volume	720 KB	1.44 MB	360 KB	1.2MB

The floppy disk cannot be used immediately after purchase. First you need to format it using the appropriate computer program.

Formatting (initialization)- the process of cutting tracks on a floppy disk, dividing the tracks into sectors, putting special marks on them. Any floppy disk can be formatted to the maximum volume possible for it or to any smaller volume intended for a given type of floppy disk. Modern formatting programs (for example, FFOR-MAT) allow you to mark a floppy disk to a non-standard size (747 KB, 1.49 MB, etc.). In order for the computer to then be able to work with this type of floppy disk, you must download a special support program (for example, PU_1700). You can also format a used floppy disk, but all data on it will be destroyed.

During operation, damaged, so-called faulty areas. Information written to the faulty section cannot be read. Therefore, you should periodically check the disks with a special program like NDD. The program identifies defective areas and marks them in such a way that when recording to disk, these areas are automatically skipped. In addition, the program can restore data that has fallen into a faulty area.

Other peripherals

1. Printer
   Unlike basic peripheral devices, those devices that we call other devices are connected to the computer depending on the specific needs of the user.
   Printer- a device for printing texts and graphic images on paper. There are several types of printers in use today.
   • Matrix printer. The principle of operation of such a printer is based on the fact that the print head containing metal needles moves along the printed line. The needles hit the paper at the right moment through the ink ribbon - the image is formed from individual dots. The ink ribbon can be wound on reels (as in a typewriter) or placed in a special box (cartridge). Dot matrix printers are the cheapest. Their print quality is usually low. The average printing speed is 1 minute per page. Dot matrix printers are not color printers.
   • Jet printer. In this type of printer, tiny droplets of ink are blown onto the paper through tiny nozzles. These printers provide fairly high print quality. The average printing speed is 1 minute per page. There are color and non-color inkjet printers.
   • Laser printer. In such printers, ink particles are transferred from a special ink drum to paper using an electric field. Print quality is high. Printing speed on average is from 4 to 15 pages per 1 minute. There are color and non-color laser printers.
2. Plotter used for printing drawings onto paper. The image is created by moving a pen with colored ink across the sheet. A regular plotter can output a drawing onto a sheet of up to A1 size (841x594 mm). But there are large plotters that display images on a sheet with dimensions up to 3x3 m. The printing speed for an A1 sheet of average fullness is 1 hour.
3. Scanner designed for entering printed text and graphic data into a computer. Having a scanner, you can not bother yourself by creating a drawing using a graphics editor, but quickly sketch the image by hand on a sheet of paper and enter it into the computer using this device. Similarly, you can enter handwritten text, which, if you have a recognition program, will be automatically converted into printed form. There are scanners manual(which are carried from above along the sheet) and tablet(the sheet is placed inside the scanner).
4. Streamer- this is a device for backing up hard drive data in case of possible loss (virus, breakdown). If you use floppies for this purpose, it will not only take a lot of floppies, but also a lot of time. The streamer quickly records data onto magnetic tape in a special cassette. The latest developments make it possible to use ordinary video cassettes for this purpose.
5. Cursor Control Devices serve to quickly move the cursor around the screen.
   • The most common among them is the type manipulator "mouse"(or just “mouse”). There is a ball inside it, which, when the mouse moves, rolls along the surface and transfers its movement to special rollers. Signals from the rollers are sent to the computer.
   • Trackball resembles a mouse turned upside down. A ball mounted on rollers is set in motion. The trackball is commonly used on notebook-type portable computers.
   • Joystick It is a handle with buttons and is usually used for games and exercise equipment.
6. Individual computers can communicate with each other via the telephone network. A user who connects his computer to such a network gets access to an almost unlimited amount of information. Computer signals are DC signals. The telephone network cannot transmit them. To convert computer signals into signals that can be transmitted over the telephone network (in other words, to modulate them - convert them into a combination of audio signals of different frequencies), a special device called modem(abbreviation for modulator-demodulator).

Multimedia components

A CD-ROM drive is functionally similar to a floppy drive, but is designed to read CDs. CD (CD-ROM - Compact-Disk-Read-Only Memory), like a floppy disk, it is used to store various data and audio and video information presented in binary form. However, if on magnetic disks binary numbers are presented in the form of two differently magnetized sections, then a different principle is used here. The spiral path consists of sections that are equal in length but different in height. To create such a form (“swelling”) the desired sections of the track are “heated” with a laser beam. When reading data, a laser beam of lower power is used. When such a beam falls on a “swollen” area, it is reflected from its surface and hits the light receiver. The beam does not reach the low area and, therefore, is not reflected. Thus, the signals in the light receiver are represented as “1” - the presence of a signal and “O” - its absence. CDs are made of aluminum or gold and encased in plastic. One CD can store up to 640 MB of information.

Homework.

1. Find and write down the following terms:
   • interface
   • program
   • microprocessor
   • controller (adapter)
   • electronic board.
   • system highway (bus)

Verification work

Choose the correct answer from the suggested ones.

1. Information about where on the disk the operating system is located is located in
   1. RAM registers;
   2. processor registers.
2. Computer capacity is
   1. number of registers in the computer;
   2. number of registers in the trigger;
   3. number of triggers in the computer;
   4. number of flip-flops in the register.
3. OU is part
   1. processor;
   2. random access memory.
4. Performs logical operations on data
   1. RAM;
5. Peripherals are connected to the motherboard via
   1. registers;
   2. slots;
   3. controllers;
   4. external devices.
6. The processor can work with 4 MB of memory
   1. 8086;
   2. 80286;
   3. 80386.
7. The processor has a clock frequency of 100 MHz
   1. 80386SX;
   2. 80386DX;
   3. 486SX;
   4. 486DX;
   5. Pentium.
8. Key peripherals include:
   1. cursor control devices, keyboard, monitor, disk drive;
   2. monitor, keyboard, disk drive;
   3. disk drive, printer, monitor;
   4. monitor, disk drive, printer, keyboard.
9. The monitor has 256 colors in graphic mode
   1. SVGA.
10. The disk sector size is
    1. 128 bytes;
    2. 256 bytes;
    3. 512 bytes;
    4. 1024 bytes.
11. A 3-inch DS/DD floppy disk can be formatted to a maximum of
    1. 360 KB;
    2. 720 KB;
    3. 1.2 MB;
    4. 1.44 MB.
12. A 3-inch DS/HD floppy disk can be formatted to a maximum of
    1. 360 KB;
    2. 720 KB;
    3. 1.2 MB;
    4. 1.44 MB.
13. The ribbon cartridge is used in
    1. inkjet printer;
    2. streamer;
    3. scanner;
    4. dot matrix printer;
    5. plotter.
14. Worst print quality
    1. inkjet printer;
    2. dot matrix printer;
    3. laser printer;
    4. plotter.
15. Designed for backing up data on a hard drive
    1. scanner;
    2. modem;
    3. trackball;
    4. plotter;
    5. streamer
16. A regular CD can store a maximum of
    1. 460 MB;
    2. 620 MB;
    3. 640 MB;
    4. 1064 MB;
    5. 1024MB.

If you are interested in the name of a device designed to interconnect a computer with other computers, then this article will definitely help you. A device for interconnecting one computer with others is called an adapter or network card. What is this element? How does he work? What functions does the network card perform? In this article you will get answers to these and many other questions.

Adapter: what is it?

An adapter is a computer peripheral device that works directly with the data transmission medium. It is thanks to the adapter or when using other communication equipment that connections with other PCs are established. This device solves the problem of ensuring the reliability of the exchange of binary data, which is presented in the form of corresponding EM signals. This data is transmitted using external communication lines. Since the adapter is a computer controller, it operates under the control of the appropriate operating system drivers. Depending on the implementation, the separation of functions between them may vary.

Adapter development

You already know that a device for connecting one computer with others is called an adapter. Let's look at how this technology developed. Adapters in the first local networks, together with a segment of coaxial cable, carried the entire range of communications equipment. It was thanks to them that interaction between computers was realized. Then direct interaction between different computers was used. This technology is still in use today. However, most modern standards also provide for a number of special communication devices, such as a switch, bridge, hub and router. These devices take over some of the functions related to data flow control.

Wrong Assumptions

Quite often you can hear or read that the device for connecting one computer with others is the processor. This statement is not true. A device for connecting one electronic computer to another is called a network card or adapter, and nothing else. It is not known for certain where this misconception came from.

Data formatting and coding function

The functions of the adapter are that information must be transmitted in the form of a frame that has a certain format. Coding refers to the presentation of information using certain signals in such a way that they can be received by the other side. At the same time, the meaning contained in them should not be lost. Let's look at this issue in more detail. There are several service fields in the frame. These fields include the address of the PC to which the data must be transferred, and the checksum of each frame. Based on the checksum, a conclusion will be drawn about the correctness of the information provided. About coding, we can say that the meaning of this procedure is to overcome interference and provide the receiving equipment with the ability to recognize the received information. There are also some technical features. For example, when using broadband cables in a local network, adapters do not use signal modulation, since this is only necessary in cases where transmission occurs over narrowband communication lines. These can be voice-frequency telephone channels.

Access function

The following function is used only in interaction with the data translation environment. It is used only in cases where access is required using a specific algorithm. This is necessary due to the operation of a shared data translation environment. However, today there has been a definite tendency to abandon this approach in favor of individual communication channels between computers and network communication devices. A similar principle is used in wired telephony.

Synchronization and conversion function

Conversion and synchronization are required to provide information in a readable form. Thanks to the adapter, information can be converted from serial to parallel form, and vice versa. This must be done for the simple reason that to simplify the synchronization task, data is transferred gradually, bit by bit. In a computer, all information is moved byte by byte. As for synchronization, we can say that it is necessary in order to maintain conflict-free interaction between the receiver and transmitter of information. This problem is successfully solved by the adapter thanks to the use of special coding methods, which do not use an additional bus with clock signals. Using this method, it is easy to ensure periodic changes in the state of the transmitted signal. In addition to problems with synchronization at the bit level, the adapter also solves similar problems regarding frames and bytes.

Technical features

Adapters are distinguished by the technology used and the internal data bus. If we talk about the bus, the following types are found here: EISA, ISA, MCA, PCI. With network technologies, everything is quite ambiguous. Typically, one adapter supports only one network technology. This is achieved through the use of various data transmission media. One of the most popular technologies is Ethernet. It easily supports coaxial, fiber optic and unshielded twisted pair cables. If the adapter can only support one medium, then transceivers and converters can be used. What are these devices?

Converters and transceivers

Transceivers are also called transceivers. They are part of the network adapter and are the terminal devices that exit the cable. It should be noted that initially the transceivers were located on cables. Then it was decided that the most convenient way would be to place it on the adapter. Instead of a transceiver, a converter could be used. It is used to coordinate information when using different data broadcast media. An example is a local home network that uses coaxial cable and twisted pair.

Conclusion

The task can be considered completed. The basic terminology and design features of the adapters are explained. Now you should not have any questions about the name of the device used to interconnect one PC with others. In addition, in this article we looked at what functions are performed by adapters, what development path they have gone through and how they can be improved. The information provided is not enough for a deeper study of this issue, but for an initial study of issues related to the construction of physical data transmission, it is quite suitable.