Introduction to Computers PDF

# Chapter 1: Introduction To Computers ## What is Computer? - A computer is a machine that manipulates data according to a list of instructions. - A computer is a device capable of performing computations and making logical decisions at speed millions and even billion of times faster than human be...

# Chapter 1: Introduction To Computers ## What is Computer? - A computer is a machine that manipulates data according to a list of instructions. - A computer is a device capable of performing computations and making logical decisions at speed millions and even billion of times faster than human beings can. - Computer is an electronic machine which is used for data processing. The output which comes after processing data through computer is known as Information. ## Why Computers? - The document shows an illustration with a number of items that can be used with computers, for example, a typewriter, paintbrushes, a compass and a calculator. ## History of Computers - **Zero th generation (1642 to 1945)** - Mechanical calculators were developed as computing devices. - **First Generation (1945 to 1955)** - In 1946 first electronic computer ENIAC (Electronic Numerical Integrator and Calculator) was developed by Mr. J.Presper Eckert and Mr. John Manuchly at University of Pennsylvania. - It used 18,000 vacuum tubes and its cost was $500,000. - Its weight was 30 tons and occupied a 30 by 50 foot space. - It produced a large amount of heat. - Its speed was very slow. - **Second generation (1955 to 1965)** - In this second generation vacuum tubes were replaced by transistors. - Speed / performance of this generation computers was improved in comparison to first-generation computers. - Size, price, and heat produced were reduced by using transistors. - **Third generation (1966 to 1970)** - In this third generation transistors were replaced by IC's (Integrated Circuits, i.e. fabrication of thousands electronic components on a single silicon chip). - Using this drastic reduction in the size of computers. - Speed / performance was high in comparison to the third generation. - Heat produced by computers was reduced. - **Fourth generation (1971 to 1980)** - In this generation, IC's were replaced by LSI (Large Scale Integrated Circuits: more numbers of electronic components on a silicon chip). - These were low cost, small size, and high performance in comparisons to third-generation computers. - **Fifth generation (1980 to present)** - In this generation LSI were replaced by VLSI (Very Large Scale Integrated Circuits). - Size and cost of these computers were very less and performance was very high. ## A computer can be divided into two main categories: 1. **Hardware** - Hardware is basically anything that you can touch with your fingers. 2. **Software** - For computer hardware to work it must follow a set of instructions that is supplied to it as software. ## Hardware - Hardware refers to the computer's physical components: - Computer Case - CPU (central processing unit... Pentium chip) - Monitor - Keyboard & Mouse - Disk Drive, Zip Drive, CD-ROM, DVD - Hard Drive - Memory (RAM) - Speakers - Printer ## Software - The term software refers to the set of instructions that directs the hardware to accomplish a task. - **System Software** - **Application Software** - **Utility Software** ## System Software/Operating System - System Software is used to control all components of a computer and serves as an interface between the user and hardware. - Control all components of a computer. - Interface between the user and hardware. ## Application Software - Application software is used or designed for the specific purpose of the user. - For example: - MS-WORD - MS-EXCEL - Corel Draw - Game - MS-POWER POINT - Acdsee - Paint - MS-ACCESS ## Utility Software - Utility Software is used to remove any problem or solve a complex situation in a computer - For example: - Partition Magic - Antivirus - Security Software - Backup utility - Data Recovery - Win Ghost ## Bits n Bytes - **Bit:** One digit, either 0 or 1 - **Byte:** any combination of 0 or 1. Also called an octet. ## Computer only understands 0 or 1 - 0 → OFF - 1 → ON ## Information Processing Cycle - Consists of four parts where each part involves one or more specific components of the computer: - **Input** - A computer receives data via an input device such as the keyboard. - **Processing** - A computer program performs operations on the data to transform it into information. - **Output** - A computer produces the output through an output device such as the monitor to display the result of the processing operations. - **Storage** - A computer stores the result of the processing operations in a storage device such as the hard disk. ## So - Computer is an electronic device which can: - accept data - process it - give the result after that processing. - and also store processed data. ## PC four major functions are: - Input data - Process data - Output information - Store data and information ## Data vs. Information - Data is a representation of a fact or idea - Examples of data: - Number: 3547 - Word: Ahmad, Kuala Lumpur, Malaysia - Information is data that has been organized or presented in a meaningful way - Examples of information: - Picture: Roll No. 3547, Name-Ahmad, City-Kuala Lumpur - Sound: Country-Malaysia ## Data vs. Instruction - The document has a diagram with three circles labelled **DATA**, **Instruction** and **Information**. Above the circles is a smaller circle labelled **2 + 2 = 4**. The diagram shows arrows from the **DATA** and **Instruction** circles to the **2 + 2 = 4** circle and then an arrow from the **2 + 2 = 4** circle to the **Information** circle. ## A Personal Computer: - The document shows an illustration of a Personal Computer. - **System unit** - **Display device** - **External device** - **Input devices** ## Enter data to be processed - Keyboard - Scanners - Mouse - Trackball - Touch screen - Microphone - Game Controller - Digital Camera ## System Unit - Cabinet that houses all components - Motherboard - CPU - Memory modules ## The System Unit - This is a personal computer component that houses other devices necessary for the computer to function. - A processor present in a system unit is the part that is like a computer’s brain. ## The System Unit - **Power Supply** - **Cooling device** - **Microprocessor (under cooling device)** - **Ports** - **Adaptor Card** - **Memory chips** - **Chassis** - **Disk drives** # Display Device - A display device is a personal computer component that enables users to view the text and graphical data associated with a computer program. ## Input Devices - An input device is a personal computer component that enables users to enter data or instructions into a computer. ## External Devices - There are several categories of external devices: - Microphone - Digital camera - Scanner - Speakers - Printer - Network device - External drive ## System Unit Components - The system unit itself has several important sub-components: - System Board - Central Processing Unit (CPU) - Memory - System Bus - Storage devices ## The System Board - The system board is the personal computer component that acts as the backbone for the entire computer system. - **AGP slot** - **Expansion slots** - **Drive interfaces** - **CPU** - **RAM slots** - **Ports** ## The Central Processing Unit (CPU) - The central processing unit (CPU), sometimes called microprocessor or just processor, is the real brains of the computer and is where most of the calculations take place. ## Memory - Memory is the personal computer component that comprises the electronic storage areas in the computer. It can be considered either volatile or non-volatile. ## The System Bus - The system bus is the main communication path between the CPU and memory. - **Hard Drive Controller** - **Video Controller** - **Memory** ## Storage Devices - A storage device is a system unit component, such as a hard drive, that enables users to save data for reuse at a later time, even after the personal computer is shut down and restarted. ## Power Supplies - A power supply is an internal computer component that converts AC power from an electrical outlet to the DC power needed by system components. - **External view** - **Internal view** - **Power switch** - **Voltage switch** - **Socket for power cord** - **Fan** - **Wires from the power supply to the system board and drives** ## Cooling Systems - Computer systems contain several components that require cooling: - The computer case - The CPU - The power supply - Some adapter cards - Some hard disk drives ## Adapter Cards - An adapter card is a printed circuit board that you install into a slot on the computer’s system board to expand the functionality of the computer. - **Circuitry** - **Phone line connection** - **Circuit to connect to phone line** - **PCI bus** ## Riser Cards - A riser card is a board that plugs in to the system board and provides additional slots for adapter cards. - **Memory slots** - **PCI/ISA slots on riser** - **Peripheral connectors** - **CPU** - **FRONT** - **REAR** ## Storage Devices - The various types of storage devices used in personal computers are: - Floppy Disk Drives (FDD) - Hard Disk Drives (HDD) - Optical Drives - Tape Drives - Solid State Storage devices ## Floppy Disk Drives (FDD) - FDD is a personal computer storage device that reads data from, and writes data to, removable disks made of flexible Mylar plastic covered with a magnetic coating and enclosed in a stiff, protective, plastic case. - **Front view 3.5-inch floppy disk drive** - **Rear view of floppy disk drive** - **Data cable** - **Power cable** - **3.5-inch floppy disk** ## Hard Disk Drives (HDD) - HDD is a personal computer storage device that uses fixed media, which means that the disk is built into the drive and the drives are not removed from the computer unless you are performing an upgrade or a repair. ## Optical Disks - An optical disk is a personal computer storage device that stores data optically, rather than magnetically. - **An external DVD drive** - **A CD-R disc** - **An internal CD-ROM drive** ## Types of Optical Disks and Drives - Optical disks and drives come in several types, such as: - CD-ROM - CD-R - CD-RW - DVD-ROM - DVD-R - DVD+R - DVD+R DL - DVD-RW - DVD+RW - DVD-RAM ## Tape Drives - A tape drive is a personal computer storage device that stores data magnetically on a removable tape that is enclosed in a tape cartridge. ## Solid - Solid state storage is a personal computer storage device that stores data in special types of memory instead of on disks or tape. - **Compact Flash card fits in here** - **USB adapter connects the Compact Flash reader to the computer** ## Personal Computer Connection Methods - The various PC connection methods are: - **Ports** - **Personal Computer Connections** - **Serial Connections** - **Parallel Connections** - **Universal Serial Bus (USB) Connections** - **IEEE 1394 and FireWire Connections** - **Small Computer Systems Interface (SCSI) Connections** - **Parallel ATA (PATA) Connections** - **Serial ATA (SATA) Connections** ## Ports - A port is a hardware connection interface on a personal computer that enables devices to be connected to the computer. - **25-pin D-shaped connector** - **6-pin round connector** - **15-pin D-shaped connector** ## Personal Computer Connection - A personal computer connection is a means by which a personal computer component is attached to other components to provide computing capabilities. - **USB Connector** - **Cable** ## Serial Connections - A serial connection is a personal computer connection that transfers data one bit at a time over a single wire. - **25-pin serial port on a serial device** - **25-pin end of serial cable connects to modem and 9-pin end connects to computer’s serial port** ## Parallel Connections - A parallel connection is a personal computer connection that transfers data eight bits at a time over eight wires and is typically used to connect a printer to a system unit. - **Parallel connector** - **Parallel cable** ## USB Connections - A USB connection is a personal computer connection that enables you to connect multiple peripherals to a single port with high performance and minimal device configuration. - **Type B connector connects to USB device** - **Type A connector connects to USB port on the computer or on a hub** ## IEEE 1394 and FireWire Connections - A FireWire connection is a personal computer connection that provides a high-speed interface for peripheral devices that are designed to use the IEEE 1394 standard. - **FireWire device** - **FireWire port** - **FireWire 6-pin connector** ## Small Computer Systems Interface (SCSI) Connections - A SCSI connection is a personal computer connection that connects internal and external components to the system unit and provides for high-speed data transfer. - **SCSI connector** - **SCSI cable** ## Parallel ATA (PATA) Connections - A PATA connection is a personal computer connection that provides a parallel data channel from a disk controller to the disk drives. - **PATA connector** ## Serial ATA (SATA) Connections - A SATA connection is a personal computer connection that provides a serial data channel between the drive controller and the disk drives. - **SATA data cable** - **SATA power cables** ## 1.5 Categories of Computer - **Personal Computer** - A single-user computer that can perform all input, processing, output and storage operations on its own. - Two types of personal computers are desktop computers and workstations. - **Mobile Computer and Mobile Devices** - **Notebook Computer** - Portable, small enough to fit on your lap. - Also called a laptop computer. - Usually more expensive than a desktop computer with equal capabilities. - **Tablet PC** - A computer that is shaped like a slate or notebook. - Normally fitted with a touch screen for users to enter input through a stylus. - **Handheld Computer** - A small computer that can easily be fit in one hand and operated by the other hand. - **Personal Digital Assistant (PDA)** - A small, portable computer built for specific purposes such as for keeping phone directories and calendars. - **Mid-Range Server** - More powerful and larger than a workstation and can support up to 4,000 users at one time. - Formerly known as a minicomputer. - **Mainframe Computer** - Very powerful, expensive computer that supports thousands of connected users. - **Supercomputer** - The fastest, most powerful, most expensive computer. - Used for applications requiring complex mathematical calculations.