Information Systems Hardware Chapter 2

Chapter Objectives Understand the important role of IS hardware in the success of modern organizations Describe key elements of IS hardware List and describe the types of computers used in organizations today Explain how hardware has evolved and where it is headed

The Importance of Information Systems Hardware Used in a rapidly changing, highly competitive global economy Relied upon for the exchange of real- time information Used on a daily basis for work, school, and fun

Key Elements of Information Systems Hardware

Input: How Information is Entered into an Information System The type of information determines how it is input –Text, numbers –Drawings, designs –Audio, video

Entering Original Text / Numbers Keyboard is most common entry device Advanced keyboards are ergonomically designed

Selecting and Pointing Mouse - most common pointing device Trackball Joysticks Touch screens Light pens

Entering Batch Data Used for entering large amounts of routine information Scanners –Convert printed text and images into digital data Text recognition software –Convert handwritten text to digital data Bar Code/Optical Character Readers –Use light to scan magnetic data

Audio and Video Microphone Digital cameras Video cameras Videocassette recorders

Processing: Transforming Inputs into Outputs All input must be converted into computer readable format Internal processing uses binary notation –Binary consists of a series of 0s and 1s –Each 0 or 1 is a bit –A combination of eight bits is a byte ASCII represents numbers and letters in binary code

Key Processing Elements Central Processing Unit (CPU) –Interprets and executes commands –Controls movement of data Primary storage –Current Secondary storage –Permanent

Figure 2.10

Primary Storage: Storage for Current Information Nonvolatile –ROM (Read Only Memory) Holds instructions to start up the computer Volatile –RAM (Random Access Memory) Stores data and program instructions the CPU is currently working on –Cache Memory Fast RAM for instructions queuing for immediate processing by the CPU

Elements of Computer Storage

Secondary Storage: Keeping Information for Later Use Permanent storage of data and programs –Magnetic tape –Floppy disks –Fixed disks –Compact discs –Optical disks

Magnetic Tape Same medium as audio cassette tapes Data stored by magnetically rearranging atoms on tape Uses sequential data access Primarily used for backing up large amounts of data

Floppy Disks Small magnetic disks Transfer data between computers Use direct data access (random access) 2.5 disk holds 1.44 MB Iomegas ZIP disk can store 100 MB

Fixed Disks Several magnetic platters in a sealed container Read/Write heads for each platter surface Greater storage capacity and data transfer rate than floppy disks

CD-ROM (Compact Disc Read-Only Memory) Uses the same technology as audio CD Uses direct access Holds 650MB Slower than fixed disk CD-R (CD-Recordable) drives available

Optical Disks Similar to CD-ROM technology May be rewritten many times Storage capacity of over 1 gigabyte (GB) on a single disk Disks and disk players relatively expensive

The Central Processing Unit: The Brain of the Computer Calculates and manipulates data Composed of millions of transistors Operates on electronic impulses Can perform more than a million instructions per second

Output: How Information is Displayed and Printed Output types are limited –Video output –Printer –Sound

Video Output Monitors –Most common video display –Uses a cathode ray tube (CRT) Liquid crystal display (LCD) –Used in portable computers Monitors embedded in many other devices

Paper-Based Displays Printers –Dot-matrix: form letters using a series of small dots –Inkjet: spray ink on paper from a small cartridge –Laser: use an electrostatic process to burn ink to the paper Plotters –Transfer designs to drafting paper

Audio Output Uses small speakers and a sound card Translates digitized data into sound

Types of Computers Supercomputers Mainframes Minicomputers Workstations Microcomputers

Supercomputers The most powerful and expensive computers Contain numerous very fast processors that work in parallel Used by researchers and scientists to solve very complex problems Cost more than 1 million dollars

Mainframes The backbone of large corporate computing The only type of computer that existed 30 years ago Used for enterprise-wide computing

Minicomputers Scaled down versions of mainframes –Smaller –Less expensive Declining market due to faster and more powerful microcomputers

Workstations The power of a minicomputer on a desktop Leaders in the market –Silicon Graphics –Sun Micro Systems –DEC Process intensive applications –Computer-Aided Design (CAD) –Web Servers

Microcomputers Often called personal computers Desktop models Portable computers Most commonly used computing technology for knowledge workers

Evolution of Information Systems Hardware Shifts in computing eras facilitated by changes in computing technology Evolution marked by significant events creating four generations of hardware

The First Generation: Vacuum Tubes ENIAC: one of the first computers – 1946 –Room-size with 18,000 vacuum tubes Replaced in 1950 by the UNIVAC Mainframe era begins

The Second Generation: Transistors Transistors generate less heat Transistors are smaller, faster, and more reliable First transistors smaller than a dime Mainframe era continues

The Third Generation: Integrated Circuits (IC) Multiple transistors on a single chip IBM First mainframe to use IC DEC PDP-11 - First minicomputer Altair 8800 first microcomputer IBM introduced the PC End of mainframe era, through mini era to personal computing era

The Fourth Generation and Beyond Present Radical new applications –Multimedia: the integration of voice, video and data –Internet for video conferencing –End-user computing

The Future of Information System Hardware Will continue the trend of smaller, faster, cheaper and ubiquitous Virtual Reality Wearable Computing Smart Cards