A hard disk is a data storage device based on the principle of magnetic recording. It records data on hard (aluminum or glass) plates or disks coated with a layer of ferromagnetic material.
Components of a hard drive
1 - Permanent magnet
2 - Head assembly commutator
3 - Rotating frame of read/write heads
4 - Actuator of disk rotation
5 - Disks (one or more)
6 – Read/write heads
7 - Integrated circuit
8 - Chassis
The integrated circuit synchronizes the hard disk drive with your computer, manages all processes, and keeps the rotation speed constant.
The drive spins the disk from 5,400 to 15,000 rpm. The spin rate of the drive depends on the type and quality of the drive's hardware. This affects how fast it runs.
The read/write heads write and read information, and a rotating frame moves them across the area of the rotating disk 60 times per second. The end of the read/write heads is split to handle multiple disks at the same time.
In operation mode, the read/write heads do not touch the surface of the disks due to the airflow. The distance between the read/write head and the disks is only a few nanometers. The lack of physical contact with the surface increases the drive's life.
In non-operational mode, the read/write heads are in a safe area where no contact with the platter surface is possible.
Data Storage
1 - Sectors
2 - Tracks
Data is stored in narrow tracks on the surface of a disk. Over 200,000 of these tracks are generated during disk production. Each track is divided into sectors. A map of tracks and sectors allows the drive to determine where to write to and read from.
The disk's surface is coated with a ferromagnetic film that stores all the information. The read/write head magnetizes a microscopic area (cell) on the disk's surface and adjusts the magnetic moment of such a cell to one of the states zero or one. A bit refers to each of these zero or one states. The bit value corresponds to the value of the magnetic field: plus or minus.
For example, a high-quality picture occupies about 29 million such cells and is distributed over twelve different sectors. This is just a very small area on the surface of the disk.
Thus, according to the law of magnetism, the thin ferromagnetic film of a disk can retain gigabytes of information.
The computer case is designed to protect the computer's internal components from external influences and mechanical damage. It is also used to maintain the required temperature inside and to shield the electromagnetic radiation generated by the internal components.
Front side of the computer case
On the front side of the computer case, there are the following:
Buttons for switching on and rebooting the computer;
Headphone and microphone sockets;
USB ports for the connection of external devices.
Back side of the computer case
Main connectors on the back of the case:
PS sockets for keyboard (green) and mouse (purple).
5mm sound card connectors. Green - line output, Blue - line input, Pink - microphone output.
USB connectors in quantity from 4 to 8 pieces.
Connector for fibre optic internet connection.
The VGA, DVI, HDMI, Displayport ports are used for connecting a monitor.
Optional connectors may be included:
Game connector for connecting a joystick or music synthesizer;
Parallel port for the connection of various peripherals, e.g. a printer.
In addition to the connectors, plugs are also provided on the backside of the case.
These blanking caps allow video and sound cards to be plugged into the back of the chassis. They can be disposable or detachable, depending on the chassis manufacturers.
Form Factor
Monoblock Computer
The computer consists of a motherboard and a monitor assembled into a single unit. There is no standard size in this form factor version. Manufacturers determine all sizes.
Vertical cases
1 – Slim tower
2 – Mini tower
3 – Midi tower
4 – Full tower
Slim-tower
It is a miniature case by size. It lacks upgradability due to the closeness of all computer components to each other.
The motherboard form factor is Micro-ATX and Mini-ATX.
Dimensions: Width 112 mm x Depth 300 mm x Height 400 mm.
Mini-tower
This case supports Micro-ATX and Mini-ATX motherboards.
Dimensions: Width 178 mm x Depth 432 mm x Height 432 mm.
Midi-tower
This is the most common form factor of the computer system unit. The dimensions allow you to install almost any motherboard, CPU heatsink, fan, and the required number of expansion boards and drives. This type of case supports the ATX motherboard (Standart-ATX) and any compatible motherboards.
Dimensions: Width 180 mm to 250 mm x Depth 430 mm to 450 mm x Height 490 mm.
Full-tower
Due to its large size any motherboard, E-ATX, and XL-ATX server boards can be placed inside. The case capacity allows you to place many drives, fans, liquid cooling systems, expansion cards, etc.
Dimensions: Width from 190 mm x Depth 482 mm x Height 820 mm.
Super-Tower и Ultra-Tower
The largest of the vertical system unit layouts. Most often used as the basis for servers, high-performance workstations, and so on.
These types of cases are available in different sizes depending on the manufacturer's preferences.
Horizontal cases
This type of case has only a horizontal design. It supports the Standart-ATX and smaller form factor motherboards.
Dimensions: Width from 533 mm x Depth from 419 mm x Height from 152 mm.
The other horizontal cases have the following standard dimensions:
Any part of a computer that consumes energy generates heat.
The heat sink is an assembly of cooling systems consisting of a series of thin tubes and reservoirs. It is required to dissipate the heat from the element being heated into the atmosphere. The air passing through the heat sink absorbs the heat.
Heat capacity is the amount of heat released (absorbed) by an object during heating (cooling).
Thermal conductivity is the ability of a material to conduct energy from the more heated parts to the less heated parts.
Heat sinks are made of thermally conductive materials with a minimum heat capacity. Heat sinks must absorb heat quickly and release it quickly. This principle is used to cool any system that transmits heat during operation.
Parts of the motherboard that become very hot during operation are equipped with heat sinks. This includes, for example, the chipset and CPU.
The power supply circuit contains heat sinksChipset (Southbridge) radiator
Types of computer cooling systems
Air-cooling
CPU heat sink
A heat sink is fitted to the processor through a special heat-conducting paste. A fan drives a large volume of air through the aluminum grid, and the heat is dissipated with great efficiency.
Standardized heat sinks and cooling fans are used to cool the CPU.
Air-cooling system in a PC unit and in a laptopSpecially designed cooling stands are available for gaming laptops.
If the enclosure is insufficiently ventilated, the fans in the system unit will drive hot air around in a circle. The heated air will not absorb the heat efficiently. As a result, the heat energy accumulated in the enclosure of the system unit will cause the system to overheat. Overheating may cause the system to burn out or cause some computer components to malfunction.
Liquid cooling system
This cooling system is more expensive to use and more complex to install in the system unit. A liquid cooling system is installed in premium gaming computers. On average, this system provides better heat dissipation than standard air cooling.
Components of the system:
Ventilator
Heat sink to dissipate the heat received from the liquid.
A heat sink (water block) is a device that draws heat from the system elements to be cooled. The heat sink transfers the heat to the liquid.
Pump for circulating liquid. The pump can be combined with a heat sink.
Liquid reservoir - this element is necessary to compensate for the thermal expansion of the liquid, easy filling, and draining of the liquid.
Hoses or pipes required to move fluid flow between system components.
A liquid flow detector can be fitted.
The liquid that is used is distilled water, often with additives that have a bactericidal or antigalvanic effect.
Some waterblocks, combined with a pump, have a display that shows temperature, fan rotation speed, frequency, voltages, and other parameters.
Classification of liquid cooling systems
A maintained liquid cooling system is a set of individual cooling system components. The pump and water block are separate. This system can be retrofitted, i.e., an additional water block for the graphics card can be installed, the pipes can be lengthened, the heatsink or the liquid can be replaced if required. This system is more complex to install than a maintenance-free liquid cooling system. In addition, there is a risk of leakage and liquid contamination.
A maintenance-free system is a set of ready-to-use sealed systems with liquid filler. The system consists of a combined waterblock and pump, one or more ventilators, tubes, and heatsink. Easy to install. There are no system upgrades or liquid changes.
Freon cooling systems
The system consists of a compressor, condenser, evaporator, dryer, and capillary tube.
The principle of operation of this cooling system is the same as that of a domestic refrigerator or air conditioner. A refrigerant, Freon, is pumped through the system. The Freon cycle is based on the Joule-Thomson effect. This effect consists of lowering the refrigerant's temperature as its pressure decreases as it flows through a constriction in the tube ducts.
The temperatures obtained with this cooling system are below zero. Due to condensate formation, it is necessary to insulate the cold part of the system.
These cooling systems are very complex to produce and install. In freon systems, it isn't easy to cool several computer components.
Water chillers
These are systems that combine a liquid cooling system with a freon unit. The principle of this system is to cool the antifreeze circulating through the system using a freon unit in a unique heat exchanger. These systems allow low-temperature cooling of several computer components.
The disadvantages of this system include the complexity of installation, the high cost, and the need for thermal insulation of the entire cooling system.
Open-type cooling systems
These units use dry ice, liquid nitrogen, or helium as a refrigerant. The refrigerant is evaporated in a special sealed container mounted on the cooling element. This type of cooling is for those who engage in extreme overclocking. This cooling system has a limited operating time and requires constant refrigerant replenishment.
This is an internal hardware codec (chipset) on the motherboard or a separate expansion card that provides input or output of audio to and from the computer. It is possible to hear the sound through data output devices.
Digital to analog converter
All modern audio recording formats use digital output. Data on CDs, Blu-ray, mp3 files are stored digitally.
Sound cards use a digital-analog converter to convert a digital code (binary) into an analog signal. The analog signal consists of current, voltage, and charge. The signal comes out through a data output device (audio speakers or headphones).
The analog-to-digital converter is required to convert analog sound (e.g. from a microphone) received by the PC into digital sound.
Types of sound cards
Internal sound card. This type of sound card is integrated into your computer's motherboard.
Discrete sound card.
An internal sound card is installed in PCI or PCIe slots. This sound card features an interface in various sound output and input ports on the back of the computer chassis. Depending on the case structure, the ports can be on the sides and at the top of the case.
External sound device.
External sound cards are necessary to enhance the quality of the output audio. They can be used when the integrated sound card has failed. They are usually connected to your computer via a USB port.
Mobile sound card
This is a feature-rich device for music lovers. It consists of input and output ports, headphone jacks, and volume control. It can be connected to a computer via PCI and PCIe and FireWire, USB, etc.
Sound card components
1 - Audio RAM. The memory, which includes the primary data for accelerated processing of the data coming to the data card;
2 - Power supply system of the sound card;
3 - Connectors for connecting various devices;
Sound card connectors
3.5mm jack for center channel or subwoofer line out;
3.5mm jack for line-level audio output;
3.5mm jack for microphone audio input;
3.5mm jack for the line-level audio output of the main stereo signal (front sound speakers or headphones);
3.5mm jack for surround sound audio output of the side speakers;
Game port - MIDI 15-pin connector for additional audio devices such as synthesizers.
This is an electromechanical device intended to read and write information from and to optical discs using a laser.
How it works
There is a spindle electric motor in the middle of the drive which rotates the drive and a drive lever with a read/write head for reading or writing data.
A SATA connector is used to connect the optical drive.
It is a plastic case that houses the laser system. There are two copper coils next to the case. These coils are used to create a magnetic field that allows the laser unit to float above the surface of the disk.
The laser diode and sensors for reading, writing, and deleting data are hidden under the lens.
Drive Classification
CD-ROM drive reads CDs only;
CD-RW drive write to CD-R/RW discs only;
DVD-ROM drive is for reading DVDs;
DVD/CD-RW drive is the same as DVD-ROM but can record on CD-R/RW discs (combo-drive);
DVD-RW drive is a drive that is able not only to read DVDs but also to write to them;
DVD-RW DL drive can burn dual-layer optical DVD media;
Blu-ray drive (BD-ROM). This is an advanced optical media technology that is based on the use of a 405-nanometer violet laser. These discs are designed to record high-resolution digital video. For example, a single-sided single-layer disc can record up to 2 hours of HDTV video at video streaming rates of up to 54 Mbps;
BD-RE drive reads and writes to Blu-ray discs;
HD DVD drive is a new generation of optical discs, which are designed primarily for storing high-definition movies (HDTV). The new media format allows you to record three times as much data as a DVD. Single-layer HD DVDs have a capacity of 15GB and dual-layer discs have a capacity of 30GB. Generally, an HD DVD drive can read all DVD and CD formats;
HD DVD-ROM drive reads HD DVDs;
HD DVD/DVD-RW drive able to record and read such disc formats as DVD-R, DVD+R, DVD-RW, DVD+RW, CD-R, CD-RW;
GD-ROM drive;
UMD drive;
DVD-RW drive that supports M-DISC recording can only record M-DISC of the DVD format, and BD-RE drive that supports M-DISC recording can record M-DISC of DVD and Blue Ray formats.
A graphics card (graphics adapter) is a device that is responsible for delivering processed data to the monitor screen as a graphic image.
A graphics card consists of a board with chips, coolers, and connectors. It is installed in the computer case.
Types of graphics cards
Discrete Graphics Card
This is a board that is installed in an available PCI or PCIe slot on the motherboard.
Integrated Graphics Card
CPUs can be equipped with a graphics core. The built-in graphics core is suitable for daily office work, surfing the Internet, and watching movies. But for visually complex applications, it will not be sufficient.
External Graphics Card
It is connected via Thunderbolt or USB connector to your computer or laptop.
Graphics card performance
The computer's CPU streams data to the graphics card.
The graphics card runs the necessary calculations and processing.
The graphics card outputs a pixel-by-pixel graphic image to the monitor screen.
Powerful graphics cards and high-resolution monitors display better, smoother, and more detailed graphics.
Component parts
Parts of the graphics card:
6-pin and 8-pin auxiliary power connectors.
The GPU power system and VRAM (Video Random Access Memory).
VRAM is a dedicated memory that the graphics processor uses to store and access pixels and other graphics data.
VRAM chips.
The graphics processing unit (GPU).
An interface connector for connecting to a PCIe slot.
SLI connector. This connector allows combining graphics cards in SLI or Crossfire mode (optional).
Connectors for image output to the monitor.
Connectors for the graphics card cooling system.
The video card cooling system consists of a heatsink and fan.
Connector for graphics cards to connect to the motherboard
All modern graphics cards use a PCI-Express x16 connector. The graphics card receives 16 interface data delivery lines from the processor. In addition to data transfer, the PCIe connector also supplies power to the graphics card.
Auxiliary power connectors will be used if the PCIe connector cannot provide full capacity to the graphics card. For this purpose, the graphics card takes extra power directly from the power supply. Modern graphics cards contain from one to several connectors with six or eight pins to connect the wire from the power supply.
Video Memory
Graphics cards come with a specific amount of VRAM, which varies depending on the model of GPU used.
GDDR (Graphics Double Data Rate) is a type of volatile random access memory (DRAM) with a double data rate (DDR). GDDR differs from DDR SDRAM (e.g., DDR3 SDRAM) by its higher-rated frequencies. GDDR has lower power consumption.
The GDDR generations used in modern graphics cards are GDDR5, GDDR6, and GDDR6X.
Video memory is used during image processing. Therefore, the higher the image's resolution, the more video memory is required. The recommended video memory capacity for modern computers is 6 GB.
Cooling System
The cooling system of modern graphics cards consists of several fans and a heatsink.
The heatsink is a device to absorb and dissipate heat from the graphics processor, memory chips, and power elements of the power supply system. The heatsink is made of several sections and plates, combined with several heat pipes.
Fans are used to dissipate heat from the heatsink. The fans can turn off when the temperature of the graphics chip is low.
A power supply unit is a device that converts AC voltage to DC voltage for connecting a computer or a computer server.
Power supplies for desktops provide output ranging from 300W to more than 1,000W.
Application
One of the main functions of a power supply is to convert the current from AC to DC (rectification). Besides driving the computer, the power supply also performs the function of stabilization and protection against minor disturbances in the supply voltage circuit.
Motherboard Compatibility
The power supply can be:
With soldered wiresModular
If the power supply with soldered wires does not adapt to the motherboard, you can use an adapter.
A modular power supply is a more expensive option than a standard power supply, but it has a lot of great advantages:
It is possible to change and use the cable that fits your motherboard without adapters.
No extra wires are hanging; they do not need to be hidden and tied up. This positively affects the air circulation inside the case.
You can choose the length of the cables.
Less unnecessary cables reduce the amount of dust in the PC case.
The form factor of commercially available power supplies
1 - The classic ATX standard power supply. It is the most common typical power supply. Dimensions: Height 86mm, Width 150mm, Depth 140mm.
2 - SFX power supply. It is suitable for small computers. SFX can be installed with a special adapter in the ATX case. Dimensions: Height 51,5mm, Width 125mm, Depth 100mm.
3 - TFX power supply. It can be used in small height or special design chassis. Dimensions: Height 65 mm, Width 85 mm, Depth 175 mm.
4 - Flex-ATX power supply. It is a solution for compact desktop systems and servers. Dimensions: Height 40,5 mm, Width 81,5 mm, Depth 150 mm.
5 - Laptop power supply.
What's inside
AC/220 means alternating current 220 volts. It is the connector for the power supply.
Many electrical devices in homes, offices are constantly turning on and off. This can cause voltage fluctuations in the mains. The power supply balances out the input voltage.
The power supply includes input filters. These are capacitors that absorb voltage surges.
The power supply converts the AC input voltage into a DC voltage of 12V, 5V, and 3.3V.
A kind of power supply
1 - Rectifier bridge;
2 - Capacitors;
3 - Pulse width modulator;
4 - Step-down transformer to 12V;
4.2 - Step-down transformer to 5V;
5 - Aluminum heatsink for low voltage diodes.
Output connectors
Each output connector includes two wires: for example, one for the +5 V and a second ground wire for potential equalization. These two wires make a loop: from the power supply to the consumer device and then back to the power supply.
The main connector is a 24-pin ATX12V. This connector provides the main power with several pins of different voltages and several special pins. One of the special connectors is the "+5 standby" output. This connector provides standby power for the computer. Standby power is required for the motherboard to stay active.
Most power supplies also have an 8-pin connector for the motherboard with two +12V lines and at least one 6-pin or 8-pin PCI Express connector. The difference between the 6-pin and 8-pin PCI Express connectors is two extra ground wires. It allows for more current for high-powered graphics cards.
The Serial ATA (SATA) connector is used to supply power to hard drives, solid-state drives, and DVD drives.
The AMP Mate-N-LOK power connector supplies one +12V, +5V output each, and two ground wires.
