CHAPTER 2.pptx Introduction to Info. Tchnology

CHAPTER 1.pptx info technology

1. Chapter 2: SYSTEM UNIT

2. System unit The system unit is the main part of a computer—it’s like the “ engine ” that makes everything work. It is usually a box or case that contains the most important components. Inside, you’ll find the processor (the brain of the computer), memory (temporary storage for data), and the motherboard (which connects all the parts together). While devices like the monitor, keyboard, and mouse are connected to the system unit, they are not part of it. The system unit is the one that does all the processing and handles the tasks you want the computer to do . System units come in different sizes and forms . Large ones are used for powerful desktop computers, while smaller ones are built into laptops and tablets. No matter the size, all system units serve the same purpose— running and controlling the computer .

3. Desktop System Units A desktop system unit contains the computer’s main electronic parts and some storage devices. The mouse, keyboard, and monitor are not part of the system unit—they are connected from the outside. This type of system unit is designed to sit on a desk and can be placed either horizontally or vertically , depending on its style and the space available.

4. Media Center System Units A media center system unit is a powerful type of desktop computer designed for home entertainment. It uses strong hardware and special graphics cards to connect with televisions and other entertainment devices. With a special operating system, such as Microsoft Windows Media Center , it can provide on-demand access to TV shows, movies, music, and games.

5. Notebook A notebook , commonly called a laptop , is a smaller and portable type of computer. It contains all the important electronic parts, storage devices, and built-in input devices such as a keyboard and touchpad (pointing device). The monitor is attached to the system unit with hinges, allowing it to open and close like a book.

6. Netbook A netbook is similar to a laptop but is smaller, lighter, less powerful, and more affordable . Netbooks are mainly designed for basic tasks like web browsing and e-mail while on the go. To save space and reduce weight, they leave out some parts, such as optical drives (CD/DVD drives).

7. Tablet PC A tablet PC is similar to a laptop but designed to be more portable and to support input using a stylus or digital pen . There are two main types: Convertible Tablet – Works like a notebook computer but has a monitor that can swivel and fold over the keyboard, allowing you to use it as a tablet. Detachable Tablet – Has a removable keyboard . With the keyboard attached, it works like a regular laptop. With the keyboard removed, it becomes more portable, and input is usually done with a stylus.

8. Handheld Computer A handheld computer is the smallest type of computer, designed to fit in the palm of your hand . Despite its size, it contains a complete computer system with electronic components, storage, and built-in input and output features. Examples of handheld computers include personal digital assistants (PDAs) and smartphones , which are the most commonly used today.

9. Components While the actual size may vary, each type of system unit has the same basic system components including system board , microprocessor , and memory .

10. SYSTEM BOARD The system board , also called the motherboard or main board , is the central circuit board of a computer. It manages communication for the entire system, connecting all the internal components such as the processor, memory, and storage devices. External devices like the keyboard , mouse , and monitor also connect through the system board. It acts like a data pathway and traffic controller , making sure all parts of the computer communicate smoothly. In a desktop computer, the system board is usually found at the bottom or along one side of the system unit. It is a large, flat board with many sockets, slots, and bus lines that hold and connect the electronic components.

11. Sockets Sockets are small connection points on the motherboard (system board) where tiny electronic parts, called chips , are inserted. These chips, often made from silicon , contain miniature circuits and are also known as silicon chips , semiconductors , or integrated circuits (ICs) . To make handling easier, chips are placed inside protective packages . These packages can be plugged directly into the sockets or attached to special cards that are then inserted into the system board. Sockets connect the motherboard to important chips such as the microprocessor (the computer’s brain) and memory chips (temporary data storage). By providing these secure connections, sockets allow the different parts of the computer to communicate and work together efficiently.

12. SLOTS Slots are special openings on the motherboard (system board) where expansion cards can be inserted. Expansion cards are extra hardware components that give the computer new or improved features. For example, adding a wireless networking card in a slot allows the computer to connect to Wi-Fi. Other common expansion cards include: Graphics cards – for better visuals and gaming performance Sound cards – for higher-quality audio Network cards – for internet connectivity In short, slots make it possible to upgrade or expand a computer’s capabilities by plugging in different types of cards.

13. BUS LINES Bus lines are like tiny roads or highways on the motherboard (system board) that allow different parts of the computer to communicate. They carry data, instructions, and signals between the electronic components, whether those parts are built into the board or connected from the outside. Even though the system boards in laptops, tablets, and handheld devices are smaller than those in desktop computers, they still use bus lines to do the same job— making sure all parts of the computer work together smoothly and efficiently .

14. MICROPROCESSOR In a microcomputer system , the central processing unit (CPU) —also called the processor —is built into a tiny electronic part called a microprocessor . The microprocessor acts as the brain of the computer , performing all the essential calculations, decision-making, and processing needed to run programs and carry out tasks.

15. Control Unit The Control Unit (CU) is the part of the CPU that manages how the computer carries out a program’s instructions. It works like a traffic director , guiding the flow of electronic signals: It moves data, instructions, and processed information between memory and the arithmetic-logic unit (ALU) . It also manages signals between the CPU and the computer’s input and output devices . In short, the Control Unit makes sure all parts of the computer work together in the right order to complete tasks correctly.

16. Arithmetic – Logic Unit The Arithmetic-Logic Unit (ALU) is a part of the CPU that performs two main types of operations: Arithmetic Operations – Basic math calculations such as addition, subtraction, multiplication, and division . Logical Operations – Comparisons between data, like checking whether one value is equal to , less than , or greater than another. In short, the ALU handles both mathematical calculations and decision-making operations that help the computer process information.

17. MICROPROCESSOR CHIPS Chip processing capacity is often measured in word size , which is the number of bits the CPU can access at one time (commonly 16, 32, or 64 bits). A 32-bit computer can access 4 bytes at a time. A 64-bit computer can access 8 bytes at a time. The larger the word size, the more data the computer can process at once, giving it greater processing capacity . Other factors, such as processing speed and how efficiently it handles instructions, also affect overall performance.

18. MICROPROCESSOR CHIPS The processing speed of a microprocessor is measured by its clock speed , which shows how many times the CPU can fetch and process data or instructions per second . Older microcomputers operate in microseconds (millionths of a second). Modern microcomputers work in nanoseconds (billionths of a second). Supercomputers are even faster, working in picoseconds (trillionths of a second). In general, the higher the clock speed , the faster the microprocessor can process information.

19. memory Memory is a place where a computer temporarily holds data, instructions, and information while it is working. Like microprocessors, memory is stored on chips that are connected to the system board (motherboard) . There are three common types of memory: Random-Access Memory (RAM) – temporary memory used while the computer is running. Read-Only Memory (ROM) – permanent memory that stores essential instructions for starting the computer. Flash Memory – non-volatile memory that can be electrically erased and reprogrammed, often used in portable devices.

20. Random - access memory Random-Access Memory (RAM) is where the computer temporarily stores the programs and data that the CPU is currently using. RAM is temporary (volatile) memory , which means that all information in RAM is lost when the computer is turned off or if there is a power failure .

21. Read – only memory Read-Only Memory (ROM) is memory that comes preloaded with information by the manufacturer. Unlike RAM, ROM is non-volatile , meaning its contents are not lost when the computer is turned off . The term “read-only” means the CPU can read or retrieve data from ROM, but it cannot change or write new information to it. ROM usually contains essential instructions for basic computer operations, such as starting the computer, accessing memory, and handling keyboard input.

22. Flash Memory Flash memory combines the features of both RAM and ROM. Like RAM, it can be updated with new information , and like ROM, it retains that information even when the power is turned off . Flash memory is used in many applications, including storing system configuration information , such as the amount of RAM installed and the types of connected devices like keyboards, mice, and storage drives. Any changes made to the computer system are saved in flash memory, allowing the system to remember them.

23. EXPANSION SLOTS & CARDS Most microcomputers allow users to upgrade or expand their systems using expansion slots on the motherboard (system board). Users can insert optional expansion cards into these slots to add new features or capabilities. The cards have ports that let you connect cables to devices outside the system unit, such as printers, monitors, or network equipment. There are many different types of expansion cards, including graphics cards , sound cards , and network cards , each adding a specific function to the computer.

24. 1. Graphics Cards – Provide high-quality 3D graphics and animations , mainly used for games, simulations, and video editing. 2. Sound Cards – Convert audio from devices like a microphone into a form the computer can process, and also convert digital signals into sound that can be played through speakers or home theater systems . 3. Network Interface Cards (NICs) – Connect a computer to a wired network , allowing it to share data, programs, and hardware with other computers. 4. Wireless Network Cards – Connect a computer to a network without cables , enabling Wi-Fi access.

25. Bus lines A bus line , or simply a bus , is a pathway that connects the CPU to other parts of the computer, including memory and components on the system board . It carries bits representing data and instructions. The bus width is like the number of lanes on a highway: the more lanes, the more data can travel at once. For example, a 64-bit bus can carry twice as much information at a time as a 32-bit bus . There are two main types of buses in every computer: System buses – Connect the CPU to memory on the motherboard. Expansion buses – Connect the CPU to other components , including expansion slots for cards and peripheral devices. In short, buses act like highways for data , helping all parts of the computer communicate efficiently.

26. Expansion buses Computer systems typically have a combination of different types of expansion buses. The principal types are PCI , USB , Firewire , SATA , and PCIe .

27. Peripheral Component Interconnect (PCI) was originally developed to handle the high video demands of graphical user interfaces. The first PCI buses had a 32-bit width and were over 20 times faster than older buses. Today, most PCI buses are 64-bit and are common in older computers for connecting expansion cards. Universal Serial Bus (USB) is widely used in modern computers. It works with the PCI bus to connect multiple external devices —like keyboards, mice, printers, and storage drives—without using expansion cards or slots. Devices can be connected in series or through a hub that links them all to the USB bus.

28. Serial Advanced Technology Attachment (SATA) is a modern bus used to connect high-speed storage devices like hard drives and SSDs to the system board. It is much faster than USB 2.0 and is now widely adopted in most computers. PCI Express (PCIe) is another modern bus found in powerful computers. Unlike the older PCI bus, which shares a single path among multiple devices, PCIe gives each device its own dedicated path , allowing much faster data transfer. PCIe is gradually replacing the older PCI bus in new computers.

29. ports A port allows external devices to connect to the system unit . Some ports connect directly to the system board (motherboard) , while others connect to expansion cards inserted into slots on the system board. Ports can be standard , found on most computers, or specialized , designed for specific devices or purposes.

30. Most microcomputers include standard ports to connect monitors, keyboards, and other devices. The most common ports are: VGA (Video Graphics Adapter) and DVI (Digital Video Interface) Ports – Connect monitors to the computer. DVI is widely used for modern digital monitors, while VGA is still included for older or lower-cost monitors. USB (Universal Serial Bus) Ports – Connect a variety of devices like keyboards, mice, printers, and storage drives. A single USB port can support multiple USB devices through hubs or daisy-chaining. Ethernet Ports – High-speed network ports that allow computers to share files or connect to the Internet via a wired connection, such as a cable modem.

31. In addition to standard ports, many computers have specialized ports for specific purposes: S/PDIF (Sony/Philips Digital Interconnect Format) Ports – Also called optical audio ports, these are used to connect a computer to high-end audio or home theater systems . HDMI (High-Definition Multimedia Interface) Ports – Carry both high-definition video and audio , allowing the computer to function as a video jukebox or HD video recorder . MIDI (Musical Instrument Digital Interface) Ports – Special serial ports for connecting musical instruments , like electronic keyboards, to the computer. The sound card converts the music into digital instructions , which can be played immediately or saved for later use.

32. cables Cables are used to connect external devices to the system unit through the ports. One end of the cable is attached to the device, and the other end has a connector that fits into the corresponding port on the system unit. In short, cables act as the link between devices and the computer , allowing data and signals to flow between them.

33. Computers need direct current (DC) to operate their electronic components and process data. DC power can come from batteries or be supplied indirectly by converting alternating current (AC) from a standard wall outlet using a power supply. In short, the computer’s electronics always use DC, even if the source is AC from the wall. Power supply

34. Desktop computers have a power supply unit inside the system unit. It plugs into a standard wall outlet, converts AC (alternating current) to DC (direct current) , and provides power to all the components inside the system unit. Notebook and tablet PCs use AC adapters , usually located outside the system unit. The adapter plugs into a wall outlet, converts AC to DC, powers the system, and can recharge the battery . These devices can run on either the AC adapter or the battery, which typically lasts four to six hours before needing a recharge.

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