ite 101 - week 4

Management Information Systems, Sixth Edition

Chapter 4:

Business Hardware

Management Information Systems, Sixth Edition 2

Objectives

• List major hardware components of computers and explain their functions

• Classify computers into major categories, and identify their strengths and weaknesses

• Identify and evaluate key criteria for deciding what computers or related devices to purchase

• Discuss the possible health hazards of computer use


Computer Hardware Components

• Hardware: physical components of computers and related electronic devices

• Consider software before hardware• Computer must handle four operations:

– Accept data

– Store data and instructions

– Process data

– Output data and/or information

Computer Hardware Components (continued)

• In general, every computer has the following components:– Input devices

– Central processing unit (CPU)

– Internal memory

– Storage

– Output devices

• Input devices: receive signals from outside of computer and transfer them into the computer




• Central processing unit (CPU)– Accepts instructions and data

– Decodes and executes instructions

– Stores results (output) in memory

• Internal (or primary) memory: stores data and instructions before and after CPU processes them– RAM: random access memory

– ROM: read-only memory



• Motherboard: circuit board containing the CPU and primary memory

• Storage: magnetic disks, magnetic tapes, optical discs, DVDs, and flash memory– Allows permanent storage

• Output devices: deliver information from the computer to the user– Monitors and printers are the most common output

devices

– Audio devices also deliver output



• Bit: Binary digit– 0 or 1

• Byte: a standard group of eight bits– Most characters can be represented by a single

byte

• Computer memory and storage capacity are measured in megabytes (MB), gigabytes (GB), and terabytes (TB)


Classification of Computers

• Computers vary in size and power• Classified by power

– Power is determined mainly by processing speed and memory size

• More powerful computers are more expensive


Supercomputers

• Supercomputers: most powerful computers at any given time– Largest in physical size and most expensive

– Designed for complex arithmetic calculations

– Generally impractical for business purposes

• Parallel processing: multiple processors running simultaneously– Also known as multiprocessing


Mainframe Computers

• Mainframe computers: store large amounts of data and business transactions– Less expensive and less powerful than

supercomputers– Often used by banks, universities, and insurance

companies as a central computer– 40-50% of world’s business data resides on

mainframes– Use multiple processors


Midrange Computers

• Midrange computers: often act as servers within organizations or through the Internet– Smaller and less powerful than mainframes

– Serve hundreds of users that connect from personal computers

– Use multiple processors


Microcomputers

• Microcomputers: personal computers, notebook computers, and handhelds

• Workstation: more powerful microcomputer used for CAD, CAM, and scientific applications

• Power of microcomputers doubles about every two years


Computers on the Go: Notebook, Handheld, and Tablet Computers

• Notebook (or laptop) computer: compact personal computer powered by rechargeable battery– New models include wireless technology

• Personal digital assistant (PDA): handheld computer– Stylus: pen-like device used to enter data through

a touch screen

• Tablet computer: PC in the form of a thick writing tablet that recognizes handwriting


Converging Technologies

• Technology convergence: building several technologies into a single piece of hardware– Prominent in handheld units

• Commonly merged technologies include:– Cell phones

– Television

– Digital cameras

– Digital sound recorder

– MP3 players


A Peek Inside the Computer

• Professionals must know about computer components to understand their power and capabilities– They use this knowledge to make good decisions

in purchasing or recommending a computer


The Central Processing Unit

• CPU has two units to store and process data– Control unit and arithmetic logic unit

• CPU is a silicon chip with multiple circuits• Also known as microprocessor• Multicore processors: processors that combine

two or more CPUs or “cores” on a single chip• Multithreading: processing more than one

program, or several parts of a program, at the same time


The Central Processing Unit (continued)



• Microprocessors are embedded with transistors• Transistor: a semiconductor that can represent

binary code’s two states• CPU machine cycle:

– Time period during which the CPU fetches, decodes, and executes each instruction

• CPU clock: special circuitry on the processor that synchronizes all tasks

• Clock rate: number of pulses per second– A machine cycle takes several clock pulses


• Data word: maximum number of bits that the control unit can fetch from primary memory in a single machine cycle– Current microcomputers have words of 32 or 64

bits• Arithmetic logic unit: the part of the CPU that

performs arithmetic and logical operations



Computer Power

• Computer power depends on processing speed and memory capacity

• Bus: electronic lines or traces used for communication inside computer

• Throughput: number of bits per second that the bus can accommodate

• MIPS: millions of instructions per second, a common measure of computer speed


Input Devices

• Computers must receive input to produce output• Input devices include machines and devices

used to enter instructions and data into computer

• Common input devices include:– Keyboard

– Trackball

– Microphone

– Scanner


Keyboard• Keyboard: an input device that contains keys

that users press to enter data– Includes letters, numbers, punctuation, and

function keys

– QWERTY: standard keyboard layout

– Dvorak: keyboard layout that allows faster typing

• Ergonomics: the study of the comfort and safety of humans in the workplace

• Ergonomic keyboard: fits the natural position of forearms and prevents injury


Mouse, Trackball, and Trackpad

• Mouse: input device that controls an on-screen pointer to facilitate point-and-click approach– Has one to five buttons for clicking, locking,

dragging• Trackball: similar to mouse, but user

manipulates a ball within the device to indicate movement on the screen

• Trackpad: cursor movement is controlled by moving a finger over a touch-sensitive pad

• Mice and similar devices can be wireless units


Touch Screen

• Touch screen: both an input and an output device– Often used for public applications, such as kiosks

– Prevalent in handheld devices, GPS devices, and mobile phones

– Allows the user to navigate and select by touching the screen


Source Data Input Devices

• Source data input devices: copy data directly from sources such as bar codes, credit cards, and checks

• Optical mark recognition devices detect positions of marks or characters

• Optical character recognition (OCR) devices try to interpret handwritten and printed text

• Magnetic-ink character recognition (MICR): detects magnetic ink on checks

Source Data Input Devices (continued)

• Magnetic strips on credit cards store encoded data

• Bar codes on products and packages store encoded information



Source Data Input Devices (continued)


Imaging

• Imaging: converts documents into images– Saves paper

– More efficient retrieval and filing

• Scanned document images can be:– Indexed and linked to relevant records in

databases

– Easily retrieved

• Original paper documents can be destroyed after scanning


Speech Recognition

• Speech (or voice) recognition: process of translating human speech into computer-readable data and instructions

• Receives input from microphone and processes it with software

• Speech-operated computers may increase noise level in offices and add distraction


Output Devices

• Output device: a device that delivers results of computer processing

• Popular output devices include:– Monitors

– Printers

– Speakers

• In the future, smell output is possible


Monitors

• Pixel (picture element): small dots that make up the images on a monitor

• Cathode-ray tube: inner side of screen has layer of phosphoric dots that make up the pixels– Electron gun receives instructions from computer

and sweeps the pixels

• Flat-panel monitor: advantages include lower power use, sharper images, and slim profile

• Liquid crystal display (LCD) monitor: uses a liquid crystal filled screen

Monitors (continued)

• Monitor price depends on:– Size, measured as the diagonal length of the

screen

– Brightness

– Contrast ratio (the higher the better)

– Pixel pitch (closeness of the pixels)

• Resolution: a measure of picture sharpness– Number of pixels in the width and height of the

screen



Printers

• Nonimpact printer: does not mechanically impact the paper– Laser printer is most common in business

– Others include ink-jet and electrothermal printers

– Speed is measured in pages per minute (ppm)

– Density measured in dots per inch (DPI)

• Impact printers: reproduce image by using mechanical impact– Dot-matrix printer: tiny pins strike ink ribbon

against paper


Storage Media

• Data must be stored on nonvolatile medium– Data is retained even when the storage device is

not connected to electrical power

• Storage devices differ in the technology used to maintain data and physical structure

• Evaluate storage devices by comparing:– Cost– Capacity– Access speed– Access mode


Modes of Access

• Sequential storage: data is organized one record after another– Must read through all records that are stored prior

to the desired record• Direct access: records are organized by physical

address on the device– A record can be accessed directly (randomly)

• Flash drives: small storage devices that connect via universal serial bus (USB)

• Direct access storage media is the only practical way to organize and query databases


Modes of Access (continued)


Magnetic Tapes

• Magnetic tapes: similar to tapes used in tape recorders and VCRs, usually as cartridges– Provide lowest cost (bytes per dollar)

– Can back up all data

– Takes a long time to copy from tape

– Tapes are unreliable after long periods of time or usage


Magnetic Disks

• Magnetic disk: most widely used storage medium– Includes hard disks and floppy disks

• Hard disk: stack of several rigid platters installed in the same box that holds the CPU– Stores up to one TB of data

– External hard disks connect to computer through USB port


Optical Discs

• Optical disc: recorded by treating the disc surface to reflect light in different ways

• Two basic categories of optical disk:– Compact discs (CDs)

– Digital video discs (DVDs)

• Compact discs: available as read-only, recordable, and rewritable

• DVDs: store 4.7 GB per side• Optical discs are slower than hard disks


Optical Tape

• Optical tape: uses same technology as optical discs to store and retrieve data

• Bits are organized sequentially, similar to magnetic tape

• Mainly used in digital video camcorders


Flash Memory

• Flash memory: rewritable memory chip that holds content without power– Consumes very little power

– Does not need a constant power supply

– Fast access times

– Relatively immune to shock or vibration

• Available as memory card and USB drive• Solid state disk: storage media that does not

have latency time


DAS, NAS, and SAN

• Direct access storage (DAS): disk or array of disks or tapes directly connected to server– Easy to deploy and manage

– Does not relieve any of server’s workload

• Network-attached storage (NAS): device designed for networked storage– Includes both the storage media and the software

to manage it

– Offloads processing from the server

– Highly scalable

DAS, NAS, and SAN (continued)• Storage area network (SAN): a network fully

devoted to storage and transfer of data– Managed separately from the rest of the LAN

– May combine DAS and NAS devices

– Can transfer larger blocks of data at higher speeds

– Expensive and complex to manage

• RAID: redundant array of independent disks– Used by DAS, NAS, and SAN

– Fault-tolerant: can continue even through disk failures due to redundancy



Business Considerations in Evaluating Storage Media

• When purchasing storage devices, managers must consider:– Purpose of data storage

– Amount of data to be stored

– Required speed of data storage and retrieval

– Unit space and portability of the device

– Cost

– Reliability and life expectancy

– Trade-offs


Business Considerations in Evaluating Storage Media (continued)


Considerations in Purchasing Hardware

• Companies must consider the following when selecting equipment to purchase:– Power of the equipment (memory size, capacity,

speed)

– Expansion slots and ports (sockets used to connect computer to external devices)

– Monitor type and resolution

– Ergonomics

– Compatibility with existing hardware, software, and networks


Considerations in Purchasing Hardware (continued)

• Considerations (continued):– Hardware footprint (physical size of equipment)

– Reliability of vendor

– Warranty policy and post-warranty support

– Power consumption and noise

– Cost

• Backward compatibility: the capability to work with older hardware or software


Scalability and Updating Hardware

• Scalability: resources can be expanded or upgraded to provide increased power

• Not all hardware is scalable• Leasing hardware is a valid option to avoid short

useful lifetime of hardware


Summary

• Understanding hardware is important for purchasing decisions

• Computers are classified according to power• All computers have a CPU to process

instructions• Clock rate measures the speed of a CPU• Data word: the number of bits the computer can

process in a single cycle


Summary (continued)

• Computer power: measured by its speed, memory size, and number of processor cores

• RAM: volatile memory that forms the largest part of computer’s memory

• ROM is nonvolatile; it does not require power• Imaging devices help process text and graphics• When evaluating external storage, consider

transfer rate, capacity, portability, and form of data organization supported


Summary (continued)

• Data is organized sequentially on tapes• Direct access storage devices such as RAM,

magnetic disks, and optical discs allow random access

• Databases require direct access storage devices• When purchasing hardware, professionals

should consider cost, power, scalability, and compatibility

• Information technology may pose health risks such as carpal tunnel syndrome