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BASIC BASIC ELECTRONICSELECTRONICS

Sarvajanik College Of Engineering and Technology

Assignment :- How Computer Works ?

-Ravi Kadiwala-Harsh Kapadiya

MODULE 2 MODULE 2 HOW COMPUTERS WORKHOW COMPUTERS WORK

2.1 – System Overview2.1 – System Overview2.2 – The Boot Process2.2 – The Boot Process2.3 – Hardware Components2.3 – Hardware Components2.4 – Memory Components2.4 – Memory Components2.5 – Display Components2.5 – Display Components2.6 – Connector Components2.6 – Connector Components2.7 – Storage Components2.7 – Storage Components2.8 – Network Components2.8 – Network Components2.9 – System Resources2.9 – System Resources2.10 – Portable Devices2.10 – Portable Devices

SYSTEM OVERVIEWSYSTEM OVERVIEW

INPUT, PROCESS, OUTPUT, AND INPUT, PROCESS, OUTPUT, AND STORAGESTORAGE

• Most operating systems provide functions to read and write data on files. Most operating systems provide functions to read and write data on files.

• It then translates requests for operations on files into operations that the disk It then translates requests for operations on files into operations that the disk controller can carry out. controller can carry out.

• The operating system performs four basic operations, The operating system performs four basic operations,

1.1. InputInput

2.2. Processing Processing

3.3. Output Output

4.4. StorageStorage

HARDWARE COMPONENTSHARDWARE COMPONENTS

COMPUTER CASESCOMPUTER CASES

• Computer cases are either desktop or tower models.Computer cases are either desktop or tower models.• The desktop modelThe desktop model sits on a desk horizontally. The sits on a desk horizontally. The

monitor can be set on top. monitor can be set on top. • The tower modelThe tower model stands upright in a vertical position stands upright in a vertical position

that allows easy placement on the floor.that allows easy placement on the floor.• Mini-tower, mid-tower, and full towerMini-tower, mid-tower, and full tower cases are cases are

available. available. • A power supply provides the needed voltage to power A power supply provides the needed voltage to power

the various electronic circuits that make up the PC. the various electronic circuits that make up the PC.

COMPUTER CASES (CONT.)COMPUTER CASES (CONT.)

POWER SUPPLIESPOWER SUPPLIES

• A power supply provides the needed A power supply provides the needed voltage to power the various electronic voltage to power the various electronic circuits that make up the PC. circuits that make up the PC.

• It receives external power and AC It receives external power and AC electricityelectricity..

• It is contained in a metal box. Within this It is contained in a metal box. Within this box, a transformer converts the current that box, a transformer converts the current that is generated from standard outlets into is generated from standard outlets into voltages and current flows that the voltages and current flows that the computer parts need to operate. computer parts need to operate.

• A fan installed in the power supply prevents A fan installed in the power supply prevents the computer and its components from the computer and its components from overheating by maintaining an air flow.overheating by maintaining an air flow.

POWER SUPPLIES (CONT.)POWER SUPPLIES (CONT.)

COOLING SYSTEMSCOOLING SYSTEMS

• The power supply fanThe power supply fan helps prevent the helps prevent the computer components from overheating by computer components from overheating by maintaining airflow in the case.maintaining airflow in the case.

• A heat sink is made of a material that A heat sink is made of a material that absorbs generated heat. It is designed to absorbs generated heat. It is designed to disperse the heat away from the CPU disperse the heat away from the CPU

• Computer cases made of aluminum create a Computer cases made of aluminum create a much cooler environment for the installed much cooler environment for the installed components. components.

• Liquid cooled cases new. They introduce Liquid cooled cases new. They introduce water as a cooling agent. Liquid cooling units water as a cooling agent. Liquid cooling units fit most cases that have a place to mount a fit most cases that have a place to mount a back exhaust fan.back exhaust fan.

THE MOTHERBOARDTHE MOTHERBOARD

• Everything else in the system Everything else in the system plugs into it, is controlled by it, plugs into it, is controlled by it, and depends on it to and depends on it to communicate with other devices communicate with other devices on the systemon the system..

• The system board is the largest The system board is the largest of the printed circuit boardsof the printed circuit boards and and every system has one. every system has one.

• It houses the CPU, the controller It houses the CPU, the controller circuitry, the bus, RAM, expansion circuitry, the bus, RAM, expansion slots for additional boards, and slots for additional boards, and ports for external devices. ports for external devices.

THE MOTHERBOARD (CONT.)THE MOTHERBOARD (CONT.)

• The motherboard chipset determines the The motherboard chipset determines the motherboard’s compatibility with several motherboard’s compatibility with several other vital system components. other vital system components.

• It consists of a group of microcircuits It consists of a group of microcircuits contained on several integrated chips or contained on several integrated chips or combined into one or two very large scale combined into one or two very large scale integration (VLSI) integrated chips. integration (VLSI) integrated chips.

• These are chips that have over 20,000 These are chips that have over 20,000 circuits. circuits.

• The motherboard chipset determines The motherboard chipset determines motherboard performance and limitations. motherboard performance and limitations.

THE MOTHERBOARD FORM FACTORSTHE MOTHERBOARD FORM FACTORS

Most new systems come Most new systems come with the ATX with the ATX motherboard form motherboard form factor. factor. •Motherboards are Motherboards are usually described by usually described by their form factors. Form their form factors. Form factors describe the factors describe the physical dimensions of physical dimensions of the motherboard. The the motherboard. The two most common form two most common form factors currently in use factors currently in use are the Baby AT are the Baby AT motherboard and the motherboard and the ATX motherboard.ATX motherboard.

Form factor Dimensions (in.) Notes

Baby AT 8.5 X 10-13Used by older PCs. Becoming outdated.

ATX 12 X 9.6The most common form factor in use today.

Mini ATX 11.2 X 8.2 Used in newer, smaller PCs.

LPX 9 X 11-13Found in older PCs. Uses a riser card to save space.

Mini LPX 8-9 X 10-11Found in older PCs. Uses a riser card to save space.

NLX 8-9 X10-13.6Found in newer PCs. Setup provides easier access to components.

THE MOTHERBOARD COMPONENTSTHE MOTHERBOARD COMPONENTS

• The components found The components found on a motherboard can on a motherboard can vary depending on its vary depending on its age and level of age and level of integration. integration.

• Some motherboards Some motherboards will have more or will have more or fewer chips or devices fewer chips or devices on board. on board.

• These are the most These are the most common items found common items found on a typical modern on a typical modern motherboard.motherboard.

THE CPU: THE CPU:

• Often referred to as the Often referred to as the brains of a computer, the brains of a computer, the CPU contains two basic CPU contains two basic componentscomponents

• Control unitControl unit – Instructs the – Instructs the rest of the computer system rest of the computer system on how to follow a program on how to follow a program instructions.instructions.

• Arithmetic/Logic Unit Arithmetic/Logic Unit (ALU)(ALU) – The ALU performs – The ALU performs both arithmetic and logical both arithmetic and logical operations. Arithmetic operations. Arithmetic operations are fundamental operations are fundamental math operations.math operations.

THE CPU (CONT.)THE CPU (CONT.)• The processor handles most of the The processor handles most of the

operations that are required of the operations that are required of the computer by processing instructions and computer by processing instructions and sending signals out, checking for sending signals out, checking for connectivity, and ensuring that operations connectivity, and ensuring that operations and hardware are functioning properly. and hardware are functioning properly.

• It acts as a messenger to major components It acts as a messenger to major components such as RAM, the monitor, and disk drives. such as RAM, the monitor, and disk drives.

THE CPU (CONT.)THE CPU (CONT.)• Terminology like socket 7, socket 370, socket 423, or Slot1, Terminology like socket 7, socket 370, socket 423, or Slot1,

will frequently be encountered. will frequently be encountered.

• Socket Socket X X (X being any numerical number) is a descriptive (X being any numerical number) is a descriptive term for the way certain processors plug into a computer term for the way certain processors plug into a computer motherboard so that it makes contact with the motherboard so that it makes contact with the motherboard's built-in circuitry or data bus. motherboard's built-in circuitry or data bus.

• Slot-type processors had a very brief lifespan (just about a Slot-type processors had a very brief lifespan (just about a year in the market). year in the market).

• Intel for its Pentium II processor moved from the socket Intel for its Pentium II processor moved from the socket configuration to a processor packaged in a cartridge that fits configuration to a processor packaged in a cartridge that fits into a slot in the motherboard. into a slot in the motherboard.

THE CPU (CONT.)THE CPU (CONT.)• The current family of the Intel Pentium microprocessors includes The current family of the Intel Pentium microprocessors includes

the Pentium II, III, IV and Xeon. the Pentium II, III, IV and Xeon.

• The Pentium class is the current standard for processor chips. The Pentium class is the current standard for processor chips. Improvements in processor speeds allow the components to get Improvements in processor speeds allow the components to get data in and out of the chip quicker. data in and out of the chip quicker.

• The best performing AMD processors are the Athlon, Thunderbird The best performing AMD processors are the Athlon, Thunderbird and Duron series. and Duron series.

• They are currently the most used microprocessors, along side the They are currently the most used microprocessors, along side the Intel Pentium IIIs.Intel Pentium IIIs.

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THE CPU (CONT.)THE CPU (CONT.)• CPU descriptions as Pentium 133, Pentium 166, or Pentium CPU descriptions as Pentium 133, Pentium 166, or Pentium

200 are well known. These numbers are specifications that 200 are well known. These numbers are specifications that indicate the maximum (reliable) operating speed at which the indicate the maximum (reliable) operating speed at which the CPU can execute instructions. CPU can execute instructions.

• The CPU speed is not controlled by the microprocessor itself, The CPU speed is not controlled by the microprocessor itself, but by an external clock located on the motherboard. The but by an external clock located on the motherboard. The speed of the processor is determined by the frequency of the speed of the processor is determined by the frequency of the clock signal.clock signal.

• Three factors determine how much information can be Three factors determine how much information can be

processed at any given time:processed at any given time:• The size of the internal bus The size of the internal bus • The size of the address bus The size of the address bus • The processor's speed ratings The processor's speed ratings

BIOSBIOS

• Read only memory (ROM) chips, Read only memory (ROM) chips, located on the motherboard, located on the motherboard, contain instructions that can be contain instructions that can be directly accessed by the directly accessed by the microprocessor.microprocessor.

• Data transfer from ROM is faster Data transfer from ROM is faster than any disk, but slower than than any disk, but slower than RAM.RAM.

• Some examples of ROM chips that Some examples of ROM chips that

can be found on the motherboard can be found on the motherboard include BIOS ROM, include BIOS ROM, electrically electrically erasable programmable read-only erasable programmable read-only memorymemory ((EEPROM), and Flash ROM. EEPROM), and Flash ROM.

BIOS (CONT.)BIOS (CONT.)• The instructions and data in the ROM chip that control the The instructions and data in the ROM chip that control the

boot process and the computer hardware are known as the boot process and the computer hardware are known as the basic input/output system (BIOS)basic input/output system (BIOS), sometimes called , sometimes called firmware. firmware.

• The ROM chip that contains the firmware is called the ROM The ROM chip that contains the firmware is called the ROM BIOS chip. BIOS chip.

• It is also referred to as ROM BIOS, or simply BIOS, and is It is also referred to as ROM BIOS, or simply BIOS, and is usually marked “BIOS” on the motherboard. usually marked “BIOS” on the motherboard.

• The responsibility of the BIOS is to serve as a liaison between The responsibility of the BIOS is to serve as a liaison between the computer operating software and the various hardware the computer operating software and the various hardware components that support it. components that support it.

BIOS (CONT.)BIOS (CONT.) • EPROM and EEPROM are ROM chips that can be erased and EPROM and EEPROM are ROM chips that can be erased and

reprogrammed. reprogrammed.

• Erasable programmable read-only memoryErasable programmable read-only memory (EPROM) is a (EPROM) is a special type of programmable read-only memory (PROM) that special type of programmable read-only memory (PROM) that can be erased by shining ultraviolet light through a clear can be erased by shining ultraviolet light through a clear window on top of the chip. window on top of the chip.

• Flash ROMs are special EEPROM chips that have been Flash ROMs are special EEPROM chips that have been developed as a result of advancements in EEPROM technology.developed as a result of advancements in EEPROM technology.

• Flash ROM holds the firmware, or BIOS, in most new systems.Flash ROM holds the firmware, or BIOS, in most new systems.

EXPANSION SLOTSEXPANSION SLOTS

• Expansion slots (sockets) Expansion slots (sockets) are receptacles on the are receptacles on the computer motherboard computer motherboard that accept printed that accept printed circuit boards. circuit boards.

• Common expansion slots Common expansion slots likely to be encountered likely to be encountered include the following:include the following:

• Industry Standard Industry Standard Architecture (ISA )Architecture (ISA )

• Peripheral Component Peripheral Component Interconnect (PCI ) Interconnect (PCI )

• Accelerated Graphics Port Accelerated Graphics Port (AGP) (AGP)

RISER CARDSRISER CARDS•Riser card – used when a computer is fully loaded to physically extends a slot so a chip or card can be plugged in. In low-profile, space-saving cases, cards are plugged into riser cards that reside parallel with the motherboard. 

RISER CARDS (CONT.)RISER CARDS (CONT.)•Audio/Modem Riser (AMR)- a plug-in card for an Intel motherboard. The AMR evolved into the Communications and Networking Riser (CNR) card, which added LAN and home networking functions.

•The CNR is a 30-pin interface that accommodates two formats making various audio/modem and audio/network combinations possible. 

AMR CNR

BUS TYPESBUS TYPES• All the basic components of the computer are connected All the basic components of the computer are connected

together by communication paths that are referred to as together by communication paths that are referred to as buses.buses.

• There are three major system bus types that can be There are three major system bus types that can be identified based on the type of information they carry. identified based on the type of information they carry.

1.1. address busaddress bus ( (a uni-directional pathway for data a uni-directional pathway for data flowflow))

2.2. data busdata bus ( (a bi-directional pathway for data flow)a bi-directional pathway for data flow)

3.3. control buscontrol bus ( (carries the control and timing signals carries the control and timing signals needed to coordinate the activities of the entire needed to coordinate the activities of the entire computercomputer))

MEMORY COMPONENTSMEMORY COMPONENTS

RAMRAM

• Random access memory (RAM)Random access memory (RAM) is the place in a computer where is the place in a computer where the OS, application programs, the OS, application programs, and data in current use are kept and data in current use are kept so that they can be quickly so that they can be quickly reached by the processorreached by the processor..

• RAM is considered temporary, or RAM is considered temporary, or volatile memory. volatile memory.

• The contents of RAM are lost The contents of RAM are lost when the computer power is when the computer power is turned off. turned off.

• The more RAM a computer has, The more RAM a computer has, the more capacity the computer the more capacity the computer has to hold and process large has to hold and process large programs and files. programs and files.

RAM (CONT.)RAM (CONT.)• There are two classes of RAM that are commonly used There are two classes of RAM that are commonly used

today. These are Static RAM (SRAM) and Dynamic RAM today. These are Static RAM (SRAM) and Dynamic RAM (DRAM). (DRAM).

• SRAM is relatively more expensive, but it is fast and SRAM is relatively more expensive, but it is fast and holds data when the power is turned off for a brief holds data when the power is turned off for a brief period of time. This is useful in such circumstances as period of time. This is useful in such circumstances as an unexpected loss of power. It is used for cache an unexpected loss of power. It is used for cache memory.memory.

• DRAM is inexpensive and somewhat slow, and requires DRAM is inexpensive and somewhat slow, and requires an uninterrupted power supply to maintain the data. an uninterrupted power supply to maintain the data. DRAM stores data in tiny capacitor that must be DRAM stores data in tiny capacitor that must be refreshed to maintain the data. Once the power is refreshed to maintain the data. Once the power is turned off, the data is lost.turned off, the data is lost.

IDENTIFYING SIMMS AND DIMMSIDENTIFYING SIMMS AND DIMMS

• A A SIMMSIMM plugs into the plugs into the motherboard with a 72-motherboard with a 72-pin or 30-pin connector. pin or 30-pin connector.

• The pins connect to the The pins connect to the system bus, creating an system bus, creating an electronic path through electronic path through which memory data can which memory data can flow to and from other flow to and from other system components.system components.

IDENTIFYING SIMMS AND DIMMS IDENTIFYING SIMMS AND DIMMS (CONT.)(CONT.)

• A A DIMMDIMM plugs into the plugs into the system's memory bank system's memory bank using a 168-pin connector. using a 168-pin connector.

• The pins establish a The pins establish a connection with the system connection with the system bus, creating an electronic bus, creating an electronic path through which data path through which data can flow between the can flow between the memory chip and other memory chip and other system components. system components.

CACHE/COASTCACHE/COAST MEMORYMEMORY • Cache is a specialized form of computer chip Cache is a specialized form of computer chip

or firmware that is designed to enhance or firmware that is designed to enhance memory performance. memory performance.

• Cache memory stores frequently used Cache memory stores frequently used information and transfers it to the processor information and transfers it to the processor faster than RAM. Most computers have two faster than RAM. Most computers have two separate memory cache levels:separate memory cache levels:

• L1 cache is located on the CPUL1 cache is located on the CPU• L2 cache is located between the CPU and L2 cache is located between the CPU and

DRAMDRAM

CACHE/COASTCACHE/COAST MEMORY MEMORY (CONT.)(CONT.)

–Some systems use COASt modules. These modules provide cache memory on many Pentium-based systems.

–The COASt module is noted for its reliability and speed because it uses the pipeline-burst cache, which is significantly faster than an SRAM cache.

–Some systems offer both SRAM sockets and a COASt module socket.

–The COASt module essentially resembles a SIMM, except that it is taller and has a different connector.

DISPLAY COMPONENTSDISPLAY COMPONENTS

MONITORS/DISPLAY DEVICESMONITORS/DISPLAY DEVICES

• Monitors are available in Monitors are available in different types, sizes, different types, sizes, and characteristics. and characteristics. When purchasing a new When purchasing a new computer, the monitor computer, the monitor may have to be may have to be purchased separately.purchased separately.

• Understanding the Understanding the characteristics of a good characteristics of a good monitor will help monitor will help determine which is best determine which is best suited for a specific suited for a specific system.system.

MONITORS/DISPLAY DEVICES MONITORS/DISPLAY DEVICES (CONT.)(CONT.)

The following terms relate to monitors. The following terms relate to monitors. • Pixels are picture elements, DotPixels are picture elements, Dot pitch, refreshpitch, refresh rate, rate,

Color depth, Video RAMColor depth, Video RAM (VRAM)(VRAM)• Resolution varies based on the number of pixelResolution varies based on the number of pixel• Monitor screen sizes are measured in inches, just like Monitor screen sizes are measured in inches, just like

televisions. The most common sizes are 14", 15", 17", televisions. The most common sizes are 14", 15", 17", 19", and 21" screens 19", and 21" screens

• Most PCs display many colors on the screen. A Most PCs display many colors on the screen. A summary of the most commonly used color depths:summary of the most commonly used color depths:

256 colors (8-bit color)256 colors (8-bit color)65,536 colors (16-bit color, also called 65K or 65,536 colors (16-bit color, also called 65K or HiColor) HiColor) 16 million colors (24-bit color, also called True Color) 16 million colors (24-bit color, also called True Color) 4 billion colors (32-bit color, also called True Color)4 billion colors (32-bit color, also called True Color)

VIDEO CARDSVIDEO CARDS

• The video card or videoThe video card or video adapter is the interface adapter is the interface between the computer between the computer and monitor. and monitor.

• The video card tells the The video card tells the monitor which pixels to monitor which pixels to light up, what color the light up, what color the pixels should be and the pixels should be and the intensity of the color. intensity of the color.

• The display capabilities The display capabilities of a computer depend on of a computer depend on both the video adapter both the video adapter and the monitor. and the monitor.