Introduction to Personal Computer

What is a Computer?

A computer is an electronic device that handles data and carries out different tasks based on given instructions.

Functions of a Computer

A computer can perform four basic functions:

Data Processing
Data can take various forms, and the processing needs can be quite diverse.
Data Storage
- Short-term storage
- Long-term storage
Data Movement
- Input-output (I/O): This refers to when data is received from or sent to a device (peripheral) directly connected to the computer.
- Data Communications: This involves transferring data over longer distances, to or from a remote device.
Control
The control unit oversees the computer’s resources and coordinates the operation of its functional components in response to instructions.

PC Components

Cases
The case contains the internal components of a computer, including the power supply, motherboard, CPU, memory, disk drives, and various adapter cards.

The term form factor refers to the physical design and appearance of a case. Common desktop computers are available in the following form factors:

Horizontal case
Full-size tower
Compact tower
All-in-one

Different case manufacturers may use their own naming conventions, such as super tower, full tower, mid tower, mini tower, cube case, and more.

Power Supplies
Computers rely on a power supply to convert AC power into the lower voltage DC power needed by internal components.

Desktop computer power supply form factors include:

Advanced Technology (AT): The original power supply used in legacy computer systems.
AT Extended (ATX): An updated version of the AT power supply.
ATX12V: The most commonly used power supply today.
EPS12V: Initially designed for network servers, but now also widely used in high-end desktop models.

Connectors

A power supply contains several connectors used to power various internal components, such as the motherboard and disk drives.

Some examples of these connectors include:

20-pin or 24-pin slotted connector
SATA keyed connector
Molex keyed connector
Berg keyed connector
4-pin to 8-pin auxiliary power connector
6/8-pin PCIe power connector

Power Supply Voltage

The different connectors in a power supply provide various voltages:

The most common voltages supplied are 3.3 volts, 5 volts, and 12 volts.
The 3.3V and 5V supplies are typically used by digital circuits, while the 12V supply is used to power motors in disk drives and fans.

Power supplies can also be categorized as single rail, dual rail, or multi rail.

A rail refers to the printed circuit board (PCB) inside the power supply to which the external cables are connected.

While computers can tolerate minor fluctuations in power, significant deviations can cause the power supply to fail.

Motherboards

The motherboard serves as the backbone of the computer.

It is a printed circuit board (PCB) that contains buses—electrical pathways that connect various electronic components.
Components can either be soldered directly onto the motherboard or connected through sockets, expansion slots, and ports.

Motherboards Components

Major components found on a motherboard include:

Central Processing Unit (CPU)
Random Access Memory (RAM)
Expansion slots
Chipset
BIOS chip and UEFI chip (used for system firmware)
SATA connectors (for storage devices)
Internal USB connectors (for front panel USB ports and internal devices)

Motherboard Chipset

The chipset is made up of integrated circuits on the motherboard that manage how system hardware interacts with the CPU and other components.

Most chipsets are divided into two main parts:

Northbridge: Handles high-speed communication between the CPU, RAM, and video card.
Southbridge: Manages communication between the CPU and slower-speed devices such as hard drives, USB ports, and expansion slots.

Motherboard Form Factors

The form factor of a motherboard refers to its size, shape, and layout, including the location of mounting holes, power connectors, and ports.

The three most common motherboard form factors are:

Advanced Technology eXtended (ATX)
Micro-ATX
ITX (including Mini-ITX and other variants)

The choice of motherboard form factor affects several key aspects of a computer’s design, including:

How components connect to the motherboard
The type and size of power supply needed
The shape and size of the computer case required to house the system properly

What is CPU?

The Central Processing Unit (CPU) is responsible for interpreting and executing instructions within a computer system.

It is a small microchip housed within a CPU package.
The CPU socket serves as the connection point between the processor and the motherboard.

Modern CPU sockets and processor packages typically follow one of these two architectures:

Pin Grid Array (PGA): The pins are located on the underside of the processor and are inserted into holes in the motherboard socket.
Land Grid Array (LGA): The pins are in the socket, while the processor has flat contact pads that sit on top of them.

Cooling Systems

Computer components operate more efficiently when kept cool.

To manage heat, systems use cooling solutions that fall into two categories:

Active cooling: Requires power to operate.
- Example: Case fans, which actively move air to cool components.
Passive cooling: Does not require power.
- Common methods include reducing the operating speed of a component or attaching heat sinks to chips to dissipate heat.

Types of Memory

A computer uses various types of memory chips, all of which store data in the form of bytes.

A byte is a unit of data made up of eight bits, each representing a value of 0 or 1.

Types of memory include:

Read-Only Memory (ROM): Non-volatile memory used to store firmware, like the BIOS or UEFI. Data in ROM cannot be modified easily.
Random Access Memory (RAM): A type of volatile memory that provides temporary working storage for data and programs actively used by the CPU. When the computer is turned off, the data in RAM is lost.

Adding more RAM can significantly improve a computer’s performance. However, the maximum RAM capacity is determined by the motherboard’s limitations.

Adapter Cards

Adapter cards enhance a computer’s functionality by either adding support for specific devices or replacing faulty ports.

Common types of adapter cards include:

Sound adapter – for audio input and output
Network Interface Card (NIC) – for wired network connections
Wireless NIC – for wireless (Wi-Fi) connectivity
Video adapter / Display adapter – for connecting and managing display devices
Capture card – for recording video input from external sources
TV tuner card – for receiving television signals
USB controller card – to add additional USB ports
eSATA card – for connecting external SATA storage devices

Computers feature expansion slots on the motherboard that allow the installation of adapter cards to enhance or extend functionality.

The adapter card’s connector must match the type of expansion slot available on the motherboard.

Common types of expansion slots include:

Peripheral Component Interconnect (PCI)
Mini-PCI – typically used in laptops
PCI eXtended (PCI-X) – an enhanced version of PCI, mainly used in servers
PCI Express (PCIe) – the most common modern slot, available in different sizes (x1, x4, x8, x16)
Riser card – used to extend slots in space-limited cases
Accelerated Graphics Port (AGP) – a legacy slot used primarily for video cards in older systems

Types of Storage Devices

Data drives provide non-volatile storage for data, meaning the data is retained even when the power is turned off.

Some drives use fixed media, while others use removable media.

Data storage devices can be classified based on the type of media used to store data:

Magnetic – such as hard disk drives (HDDs) and tape drives
Solid state – such as solid state drives (SSDs)
Optical – such as CDs and DVDs

Magnetic Media Storage

This type of storage represents binary values as magnetized or non-magnetized physical areas on magnetic media.

Common types of magnetic media storage drives include:

Hard Disk Drive (HDD) – Traditional magnetic disk devices with storage capacities ranging from gigabytes (GBs) to terabytes (TBs).
Tape Drive – Primarily used for data archiving. Tape drives use a magnetic read/write head and removable tape cartridges.
- Common tape storage capacities vary from a few GBs to many TBs.

Semiconductor Storage

Solid-State Drives (SSDs) store data as electrical charges in semiconductor flash memory, making them much faster than traditional magnetic HDDs.

Advantages of SSDs over HDDs include:

No moving parts
Silent operation
More energy-efficient
Generate less heat

SSDs are available in three common form factors:

Disc drive form factor – Similar to an HDD, typically used in 2.5-inch drive bays.
Expansion cards – These plug directly into the motherboard and mount in the computer case like other expansion cards.
mSATA or M.2 modules – Compact form factors that use a special socket. M.2 is a standard for computer expansion cards.

The Non-Volatile Memory Express (NVMe) specification was developed to optimize the performance of SSDs by providing a standard interface between SSDs, the PCIe bus, and operating systems.

NVMe allows SSDs to connect directly to the PCIe bus without the need for special drivers, enhancing speed and efficiency.

Solid-State Hybrid Drives (SSHDs) offer a middle ground between traditional magnetic HDDs and SSDs:

Faster than HDDs but more affordable than SSDs.
Combine a magnetic HDD with onboard flash memory, which acts as a non-volatile cache to improve performance.

Types of Optical Storage Devices

Optical drives are removable media storage devices that use lasers to read and write data on optical media.

They were developed to address the storage capacity limitations of older removable magnetic media, such as floppy disks.

There are three main types of optical drives:

Compact Disc (CD) – Used for audio and data storage.
Digital Versatile Disc (DVD) – Used for digital video and data storage.
Blu-ray Disc (BD) – Used for HD digital video and data storage.

Video Ports and Cables

A video port connects a monitor to a computer using a cable.

Video ports and monitor cables transfer either analog signals, digital signals, or both.

Common video ports and cables include:

Digital Visual Interface (DVI)
DisplayPort
High-Definition Multimedia Interface (HDMI)
Thunderbolt 1 or 2
Thunderbolt 3
Video Graphics Array (VGA)
Radio Corporation of America (RCA)

Other Ports and Cables

Input/Output (I/O) ports on a computer connect peripheral devices like printers, scanners, and portable drives.

In addition to standard I/O ports, a computer may also have the following ports:

Personal System 2 (PS/2) – Typically used for connecting keyboards and mice.
Audio and game port – For connecting audio devices and game controllers.
Network – For wired network connections, often an Ethernet port.
Serial AT Attachment (SATA) – Used for connecting storage devices like hard drives and SSDs.
Integrated Drive Electronics (IDE) – An older standard for connecting storage devices, now largely replaced by SATA.
Universal Serial Bus (USB) – A versatile port used to connect a wide range of peripheral devices such as keyboards, mice, external storage, and more.

Adapters and Converters

There are many connection standards in use today, and the components used to facilitate these connections are called adapters and converters:

Converter – Performs the same function as an adapter but also translates signals from one technology to another.
Adapter – Physically connects one technology to another.

Examples of adapters and converters include:

DVI to VGA adapter
USB to Ethernet adapter
USB to PS/2 adapter
DVI to HDMI adapter
Molex to SATA adapter
HDMI to VGA converter

The Original Input Devices

Input devices allow the user to communicate with a computer.

Some of the first and most commonly used input devices include:

Keyboard and Mouse – These are the two most commonly used input devices for interacting with a computer.
ADF / Flatbed Scanner – These devices digitize images or documents for storage or manipulation on a computer.
Joystick and Gamepad – These devices are primarily used for playing video games and controlling game characters or functions.
KVM Switch – A hardware device that allows a user to control multiple computers using a single keyboard, monitor, and mouse.

New Input Devices

Some new input devices include touch screens, stylus, magnetic strip readers, and barcode scanners:

Touch screen – An input device with a touch or pressure-sensitive screen, allowing users to interact directly by tapping, swiping, or pressing on the screen.
Stylus – A pen-like tool used with a digitizer that enables designers or artists to create artwork or write with precision on a touch-sensitive surface.
Magnetic strip reader – A device that reads information magnetically encoded on the back of plastic cards, such as credit or ID cards.
Barcode scanner – A device that reads the information contained in barcodes affixed to products, often used in retail and inventory systems.

More New Input Devices

A few newer input devices include:

Digital camera – Devices that capture digital images and videos, often used for photography or video recording.
Webcams – Video cameras that can be integrated into a computer or attached externally, commonly used for video conferencing and streaming.
Signature pad – A device that electronically captures a person’s signature, often used in digital transactions or document signing.
Smart card reader – A device used to authenticate the user by reading a smart card, which is typically the size of a credit card and contains an embedded microprocessor under a gold contact pad.
Microphone – A device that allows a user to speak into a computer, converting their voice into digital data for voice recognition, communication, or recording purposes.

Most Recent Input Devices

The newest input devices include NFC devices and terminals, facial recognition scanners, fingerprint scanners, voice recognition scanners, and virtual reality headsets:

NFC devices and terminals – Near Field Communication (NFC) devices, such as tap-to-pay systems, allowing users to make secure transactions by tapping their device near a terminal.
Facial recognition scanners – Devices that identify a user based on their unique facial features, often used for security or authentication purposes.
Fingerprint scanners – Devices that identify a user based on their unique fingerprint, commonly used in security systems and personal devices.
Voice recognition scanners – Devices that authenticate a user or provide commands based on their unique voice patterns, used in voice-activated assistants and security.
Virtual reality headset – A device worn on the head, used with computer games, simulators, and training applications to provide immersive virtual reality (VR) experiences.

What are output Devices?

An output device takes binary information from the computer and converts it into a form that is easily understood by the user.

Examples of output devices include:

Monitors – Display visual information to the user.
Projectors – Project visual content onto a larger surface, often used for presentations or entertainment.
VR headsets – Provide immersive virtual reality experiences by displaying 3D visuals and interacting with the user.
Printers – Produce physical copies of documents or images from digital data.
Speakers – Convert digital audio signals into sound.
Headphones – Similar to speakers, but designed for personal audio output, usually worn over the ears.

Monitors and Projects

Most monitors use one of three types of technology, including:

LCD (Liquid Crystal Display) – Uses liquid crystals to control light and produce images.
LED (Light Emitting Diode) – A type of LCD that uses LED backlighting for brighter and more energy-efficient displays.
OLED (Organic Light Emitting Diode) – Each pixel emits its own light, providing deeper blacks and better contrast compared to traditional LCDs.

Most video projectors use either LCD or DLP technology:

DLP (Digital Light Processing) – Uses digital micromirror devices to project images, offering high-quality visuals and excellent color accuracy.
Projectors have different lumens ratings, which determine the brightness of the projected image. The higher the lumens, the brighter the image, making it easier to see in well-lit environments.

VR and AR Headsets

Virtual Reality (VR) uses computer technology to create a simulated, three-dimensional environment that immerses users in a completely virtual world.

A VR headset completely covers the upper portion of the user’s face, blocking out any ambient light from their surroundings, providing a fully immersive experience.

Augmented Reality (AR), on the other hand, uses similar technology but superimposes digital images and audio over the real world in real-time.

AR allows users to interact with and access immediate information about their physical surroundings.
An AR headset typically does not block ambient light, allowing users to see and interact with both the digital and physical worlds simultaneously.

Printers

Printers are output devices that create hard copies of files.

A hard copy can be a printout on a sheet of paper or a physical object created by a 3D printer.

Different types of printers include:

Inkjet – Uses liquid ink to spray tiny droplets onto paper to create images and text.
Impact – Uses a hammering mechanism to print by striking an inked ribbon onto paper (e.g., dot matrix printers).
Thermal – Uses heat to transfer ink onto paper, commonly used in receipt printers.
Laser – Uses a laser beam to form patterns on a drum that attracts toner and transfers it onto paper.
3D printers – Create three-dimensional objects by layering material (often plastic) based on digital models.

Printers can use either wired or wireless connections for communication.

Printing materials such as ink, toner, or liquid plastic are required depending on the printer type.
All printers rely on a driver to communicate with the operating system, enabling proper functioning.

Speakers and Headphones

Speakers are a type of auditory output device, converting digital audio signals from the computer into sound.

Most computers and mobile devices have audio support either integrated into the motherboard or provided through an adapter card.
Headphones, earbuds, and earphones found in headsets are also types of auditory output devices.
These audio devices may be wired or wireless, with some models being Wi-Fi or Bluetooth-enabled for more flexible connectivity options.

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