Computers and Applications

Computers and Applications CCNA Discovery: Chapter 1

Contents Section 1-1: • Computer Systems • Applications • Types of Computers • Binary Numbers Section 1-2 • Computer System Requirements • Computing Devices • Installations and Upgrades

Computer Systems • In order for a computer system to operate, these 3 components must work together • Hardware • Operating System software • Application Software

Hardware • Hardware- the physical components of the computer, or the electronic pieces that make up a computer system • Hardware includes external and internal components

Software • Software - the programs that tell the computer what to do • Operating System software is a set of computer programs that manages the hardware of a computer. • An operating system controls the resources on a computer, including memory and disk storage. • Examples: Windows XP, Windows Vista, Linux, Mac OS

Application Software • Application software is a program loaded on the computer that performs a specific task for a user or another application. • Examples: word processor, web browser, graphics editor, spreadsheet, mail reader

Applications • The computer is only as useful as the program or application on it. • Applications can be divided into two general categories: • Business/Industry Software – designed to be used by specific businesses • Examples: The Medical industry, CAD programs • General Use Software – designed for a wide range of users • Example: Graphic Editors, Office Suites

Local vs. Network Applications • Local applications - Programs, such as word processors, that are stored on the hard disk of the computer. • The application runs only on that computer. • Network applications – Programs that are designed to run over a network, such as the Internet. • A network application has two components, one that runs on the local computer and one that runs on a remote computer. • Server: runs on the remote computer • Client: runs on the local computer • Examples: Email, Web browser, FTP, File Sharing • Most computers have a combination of local and network applications installed.

Classes of Computers • There are many different types of computers available including: • Mainframes • Servers • Desktops • Workstations • Laptops • Hand-held portable devices • Each type of computer is designed with a particular purpose in mind

Mainframes • Mainframes: a mainframe is a large, powerful computer stored in a secure location, which allows users access through dumb terminals • Dumb terminals usually consist of just a monitor, keyboard, and a communication port to the mainframe • Mainframes are very secure because management is centralized and users have very little control over the system • Although mainframes are expensive, the use of dumb terminals can be a low cost alternative to providing users with complete computer systems

Servers • Servers are high performance computers used in businesses and other organizations. • Servers provide services to many end users or clients. • Services: file storage, email storage, web pages, print sharing • Servers usually have specialized hardware that is optimized for quick response time to multiple network requests. • multiple Central Processing Units (CPUs) • large amounts of Random Access Memory (RAM) • multiple high capacity disk drives

Redundancy and Security • The services provided by a server are often important and may need to be available to users at all times. • Servers, therefore, often contain duplicate, or redundant, parts to prevent them from failing. • Automatic and manual backups of data are also usually done on a regular basis. • Servers are usually kept in secure areas where access is controlled.

Server Design • Servers come in many different designs • standalone tower design • rack mounted • blade design. • A server is typically used as a storage point and not a day-to-day end-user device, so it may not have a monitor or keyboard, or may share a monitor and keyboard with other devices

Desktops • Desktop PCs: a desktop PC is a stand-alone computer, that is not dependent on other computers to operate • Desktop PCs are cheaper than mainframe systems, and allow users to use a GUI (graphical user interface) instead of text-based entry • They are also standardized in terms of hardware and operating systems • Desktops support many different types of hardware and application software

Workstations • Workstations are high-powered business computers that are designed for specialized, high-end applications • Engineering programs like CAD • 3-D graphics design • Video animation • Virtual reality simulation. • They may also be used as management stations for telecommunications or medical equipment. • Workstation Hardware is usually more advanced than a desktop PC: • multiple CPUs • large amounts of RAM • multiple, high-capacity disk drives • powerful graphics capabilities • large monitor or multiple monitors

Portable Devices Portable devices vary in size, power and graphic capability: • Laptop or notebook PC • Tablet PC • Pocket PC • Personal Digital Assistant (PDA) • Gaming device • Cell phones • Laptops are comparable to desktops in usage and processing capability. • Built to be lightweight and use less power • Many hardware is built-in: mouse, monitor and keyboard • Have a limited number of configurations available, such as video options and connection types • Not as easily upgradeable as the desktop

PDAs and Pocket PCs • PDAs and pocket PCs have less hardware capabilities • less powerful CPUs than a laptop • less RAM than a laptop • small screens with limited display capabilities • small input keyboard. • Multi-Function Devices: • combines a PDA, cell phone, digital camera, and music player • provides Internet access and wireless networking capability • limited processing power similar to the PDA • Advantages of Portable Computers: • information and services are available immediately, almost anywhere

Binary • In a computer, information is represented and stored in a digital binary format. • Computers are electronic devices, made up of millions of tiny circuits, which act like switches • Each switch can have 2 states: on or off • A computer relies on the binary number system to process data: it uses the numbers 1 and 0 to represent on and off • Everything that is done on a computer must be translated into a series of 1’s and 0’s, so the computer can interpret it • The term bit is an abbreviation of binary digit and represents the smallest piece of data – a 1 or 0

ASCII Code • Computers use binary codes to represent and interpret letters, numbers and special characters with bits. • The ASCII Code is used to represent each character as a string of bits. • Each character is assigned a number, which is then converted to binary • Capital letter: A = 01000001 • Number: 9 = 00111001 • Special character: # = 00100011

ASCII Chart

Data Capacity • Information or data capacity in computers is measured in terms of the bit • Each group of eight bits, such as the representations of letters and numbers, is known as a byte. Unit Measurement Used to measure bit a 0 or 1 a binary decision byte 8 bits 1 character Kilobyte (KB) 1,000 bytes text documents Megabtye (MB) 1 million bytes (1,000 kb) multimedia files, RAM Gigabyte (GB) 1 billion bytes (1,000 mb) hard drives, DVDs Terabyte (TB) 1 trillion bytes (1,000 gb) High capacity drive Petabyte (PB) 1,000 terabytes (250 bytes) National databases Exabyte (EB) 1 billion GB (1 quintillion bytes) all words ever spoken = 5 EB Note: 1kb = 1 kilobit while 1KB = 1 kilobyte

Bandwidth • Bandwidth is a measurement of how much information can be transferred within a particular period of time • Bandwidth is measured in terms of bits per second Kilobits per Second (Kbps) KiloBytes per Second (KBps) Megabits per Second (Mbps) MegaBytes per Second (MBps) Gigabits per Second (Gbps) GigaBytes per Second (GBps)

Bandwidth Calculations: Download Time = Size of File Bandwidth Example: How long would it take to transfer a 10 MB file over 1.54 Mbps connection? Time =10 MB 1.54 Mbps (10 MB x 8) = 80 Mb 1.54 Mb/s Time =80 Mb 1.54 Mb/s Time =80 1.54 s Time =52 seconds

Decimal Numbering System Example: 2134 = (2x103) + (1x102) + (3x101) + (4x100)

Binary Numbers • The binary number system uses only two symbols – 0 and 1 – instead of the ten symbols used in the decimal numbering system. • The position, or place, of each digit represents the number 2 – the base number – raised to a power (exponent), based on its position (20, 21, 22, 23, 24, etc.)

Binary Numbering System

256: The magic number • How many different number combinations can be made with 8 bits? • If you do the math you will see that 8 bits, or 1 byte, can represent 256 different values • The numbers 0 to 255 = 256 possible values • The number 256 is important in computing: • the RGB color scheme contains 256 values for each of red, green, and blue.

Binary to Decimal Conversion 1 0 0 1 1 0 0 1 10011001 = • Write out each bit in the binary number over its place value • Multiply out each bit value (0 or 1) by its place value (ex. 1 x 128) • Add up all the numbers to get the decimal equivalent = (1 x 128) + (0 x 64) + (0 x 32) + (1 x 16) + (1 x 8) + (0 x 4) + (0 x 2) + (1 x 1) = 128 + 0 + 0 + 16 + 8 + 0 + 0 + 1 = 153

Decimal to Binary Conversion • Divide the Decimal number by the highest order bit in the 8-bit binary number (the 128th place) • If the decimal number can be divided at least once by the place value (ex. 200 / 128), then put a 1 in that place value, and carry the remainder • If the number can not be divided by the place value, put a 0 in that place value and carry the remainder • Continue to divide the decimal number by each binary place value, until you get to the 1’s place Example: Convert the decimal number 199 to a binary number. R71 R7 R3 R1 1 1 0 0 0 1 1 1 199 =

Counting in Binary • It is very useful to be able to count in binary, at least up to the number 15, when working with computers and networks • Counting in binary is usually done using only the 4 least-order bits • the first 4 bits on the right side of an 8 bit number are called the least-order bits • These represent the 8’s, 4’s, 2’s and 1’s place • The 4 high-order bits on the left (128, 64, 32 and 16 place) are assumed to be all 0’s, therefore they can be left out.

Binary Counting Full Binary Decimal Binary Counting 00000000 0 0000 00000001 1 0001 00000010 2 0010 00000011 3 0011 00000100 4 0100 00000101 5 0101 00000110 6 0110 00000111 7 0111 00001000 8 1000 00001001 9 1001 00001010 10 1010 00001010 11 1011 00001100 12 1100 00001101 13 1101 00001110 14 1110 00001111 15 1111

Bit Patterns • As you start working with IP addresses and subnets, it will be very useful to learn to recognize some common bit patterns that are used in computing and networking. • Common bit Patterns in Networking: • 10000000 = 128 • 11000000 = 192 • 11100000 = 224 • 11110000 = 240 • 11111000 = 248 • 11111100 = 252 • 11111110 = 254 • 11111111 = 255

Computer System Requirements • There are many types of computers. • What makes one computer better for a certain task are the components and peripherals that make up the computer system. • It is important to determine the intended uses for a computer before deciding on the type of computer and components to purchase. • The final product must match the requirements of the end user.

Important Components • Important components to consider when purchasing a computer: • Motherboard • Processor • RAM • Storage • Adapter cards • Case • Power Supply

Purchase Options When purchasing a computer, there are 2 main options: • Preassembled computers • Custom Built computers Each option has its advantages and its disadvantages

Preassembled Computers Advantages: • Lower cost • Adequate to perform most applications • No waiting period for assembly • Typically used by less knowledgeable consumers who do not require special needs Disadvantages: • Often lack the performance level that can be obtained from custom built computers

Custom Built Computers Advantages: • The end-user can specify exact components that meet user needs • Generally support higher performance applications such as graphics, gaming, and server applications Disadvantages: • Generally more costly than a preassembled device • Longer waiting periods for assembly

Computing Devices • A computer performs 4 main tasks, and each requires a different type of hardware device • Input Devices: • Allow the user to give data to the computer • Input devices include: keyboard, mouse, scanner, tablet, microphone • Processing Device: • Reads and executes data and instructions • Data must be read, organized and checked for accuracy • The CPU (central processing unit) performs this task • Output Devices • Allow the computer to give data back to the user • Output devices include: monitor, printer, speakers • Storage Devices • Allows data to be stored for use at a later date • Storage devices include :hard drive, floppy drive, CD/DVD burner, flash drives, tape backups

Types of Computing Devices There are 4 types of Computing Devices: Input Output storage networking devices Examples: Input devices - trackball, joystick, scanner, digital camera, digitizer, barcode reader, microphone Output devices - printer, plotter, speakers, headphones Storage devices - secondary hard drive, external CD/DVD devices, flash drives Networking - external modems, external NIC

Motherboard • The motherboard is a large circuit board used to connect the electronics and circuitry that make up the computer system. • Motherboards contain connectors which allow major system components such as the CPU and RAM to attach to the board. • The motherboard moves data between the various connections and system components. • A motherboard can also contain connector slots for network, video and sound cards. • Many motherboards now come equipped with these features as integrated components.

Choosing a Motherboard When selecting a motherboard it must: • Support the selected CPU type and speed • Support the amount and type of system RAM required by the applications • Have sufficient slots of the correct type to accept all required interface cards • Have sufficient interfaces of the correct type

Central Processing Unit (CPU) • The CPU is the nerve center of the computer system. • It is the component that processes all of the data within the machine. • The type of CPU should be the first decision made when building or updating a computer system. • Important factors when selecting a CPU are: • processor speed • bus speed • Socket type – must be compatible with the mobo

Processor Speed • Processor speed measures how fast a CPU cycles information • Usually measured in MHz or GHz • The higher the speed the faster the performance • Faster processors consume more power and create more heat • Mobile devices, such as laptop computers, typically use processors that are slower and consume less power in order to extend the time they can operate using batteries.

Bus Speed • CPUs transfer data between various types of memory on the system board during its operation. • The Bus is the pathway for this movement of data • The faster the bus, the faster the computer will be

Choosing a CPU • When selecting a CPU, keep in mind that applications continue to evolve, if the CPU is not sufficiently fast, the overall performance, measured in terms of response time, will be slower. • The CPU is mounted through a socket on the motherboard and is normally the largest component on the board. • The motherboard must be equipped with a compatible socket to accept the selected CPU.

Random Access Memory (RAM) • RAM is the temporary data storage in a computer • It is used to store data and instructions that are currently being processed by the CPU. • Data in RAM is accessed in any order, or at random, as needed. • All computer programs run from RAM. • Besides the CPU, the amount of RAM is the most important factor in computer performance.

Choosing RAM • When choosing how much RAM to put in a computer, you should consider the following: • The amount of Multi-Tasking required • Most computers are capable of running multiple applications simultaneously, or multi-tasking. • All of these applications require memory. • The more applications that need to run simultaneously, the more RAM required. • How many processors the system has • More RAM is needed for multiple processor systems • CPU and bus speed • A faster CPU and bus require more RAM • The RAM configuration that the motherboard will support

Adapter Cards • Adapter cards add functionality to a computer system. • They plug into a connector or slot on the motherboard • Many motherboards have built-in components that perform the same functions as adapter cards • On-Board components do not usually produce the same level of performance as adapter cards

Adapter Cards Common adapter cards: • Video cards • Sound cards • Network interface cards • Modems • Interface cards • Controller cards Sound Card Video Card NIC

NICs • A Network Interface Card (NIC) is the computer's interface with the LAN. • The NIC communicates with the network through serial connections and communicates with the computer through parallel connections. • NICs are expansion cards (PCI or ISA) that can be installed in one of the computer's expansion slots. • The network cable plugs in to the computer through the adapter card or NIC.

Computers and Applications