3 - 1 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved.

3 - 2 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Computer Hardware Chapter 3

3 - 3 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. 1.Identify the major types and uses of microcomputer, midrange, and mainframe computer systems. 2.Outline the major technologies and uses of computer peripherals for input, output, and storage. Learning Objectives

3 - 4 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Learning Objectives 3.Identify and give examples of the components and functions of a computer system. 4.Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selections.

3 - 5 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. What is a Computer? Definition: All computers are systems of input, processing, output, storage, and control components.

3 - 6 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Types of Computer Systems

3 - 7 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Microcomputer Systems Personal Computer (PC) – microcomputer for use by an individual Professional Workstation – a powerful, networked PC for business professionals Laptop – small, portable PC

3 - 8 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Microcomputer Systems Network Server – more powerful microcomputers that coordinate telecommunications and resource sharing in small local area networks and Internet and intranet websites Computer Terminals – depend on servers for software, storage and processing power

3 - 9 Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Microcomputer Systems Network Computers – low-cost, sealed microcomputers with no or minimal disk storage that are linked to the network Information Appliances – hand-held microcomputer devices

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. PC Features

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Midrange Systems Definition: Primarily high-end network servers and other types of servers that can handle the large-scale processing of many business applications.

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Mainframe Systems Definition: Large, fast, and powerful computer systems

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Supercomputer Systems Definition: Extremely powerful computer systems specifically designed for scientific, engineering, and business applications requiring extremely high speeds for massive numeric computations

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Hardware Organized by System Functions Input Devices convert data into electronic form for direct entry or through a telecommunications network into a computer system Processing Components primarily the Central Processing Unit (CPU) Arithmetic-Logic Unit (ALU) - perform arithmetic and logic functions required to execute software instructions

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Hardware Organized by System Functions Output Devices convert electronic information produced by the computer system into human- intelligible form for presentation to end users Storage Devices store data and software instructions needed for processing Control Components primarily the CPU’s Control Unit which interprets software instructions and transmits directions that control the activities of the other components of the computer system

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Computer Processing Speeds Millisecond – thousandth of a second Microsecond – millionth of a second Nanosecond – billionth of a second Picosecond – trillionth of a second

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Computer Clock Speeds MIPS – million instructions per second Megahertz (MHz) – millions of cycles per second Gigahertz (GHz) – billions of cycles per second

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Throughput Definition: Ability of a microprocessor to perform useful computation or data processing assignments during a given period of time Depends on: Buses – size of circuitry paths that interconnect microprocessor components Registers – that process instructions Cache – high-speed memory Specialized Processors

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Peripherals Advice

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Online vs. Offline Online – devices are separate from but can be electronically connected to and controlled by a CPU Offline – devices are separate from and not under the control of the CPU

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Input Technologies Keyboard Pointing Devices Pen-Based Computing Speech Recognition Systems Optical Scanning

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Graphical User Interface (GUI) Definition: Icons, menus, windows, buttons, bars, etc used for user selection

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Pointing Devices Electronic Mouse – Moving mouse on pad moves cursor on screen. Pressing buttons on mouse activates activities represented by selected icons. Trackball – Stationary device with a roller ball on top used to move cursor on screen. Pointing Stick – Small button-like device which moves cursor in direction of pressure placed on stick.

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Pointing Devices Touchpad – Small rectangular touch- sensitive surface which moves the cursor in the direction of finger moves on the pad. Touch Screen – Video display screen that emits a grid of infrared beams, sound waves, or a slight electric current that is broken when the screen is touched.

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Pen-based Computing Definition: Pressure-sensitive layer under slate-like liquid crystal display screen and software that digitizes handwriting, hand printing, and hand drawing

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Speech Recognition Systems Discrete – user must pause between each spoken word Continuous – software can recognize conversationally-paced speech

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Optical Scanning Definition: Devices that read text or graphics and convert them into digital input for your computer

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Optical Character Recognition (OCR) Definition: The machine identification of printed characters through the use of light- sensitive devices

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Other Input Technologies Magnetic Stripe – devices that read data stored in the magnetic stripe on the back of cards Smart Cards – devices that read a microprocessor chip embedded in a card

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Other Input Technologies Digital cameras – devices that allow you to capture, store, and download still photos and full motion pictures Magnetic Ink Recognition (MICR) – devices that can read characters printed on source documents with an iron oxide- based ink

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Output Technologies Video Output Printed Output Voice Response

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Video Output Cathode Ray Tube (CRT) – similar to vacuum tubes in television Liquid Crystal Display (LCD) – electronic visual displays that form characters by applying an electrical charge to selected silicon crystals

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Printed Output Inkjet Printers – spray ink onto the page Laser Printers – use an electrostatic process similar to a photocopying machine

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Storage Trade-Offs

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Binary Representation Definition: Data are processed and stored in a computer system through the presence or absence of electronic or magnetic signals in the computer’s circuitry or in the media it uses

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Bit vs. Byte Bit – binary digit, which can have a value of either zero or one Byte – basic grouping of bits that the computer operates as a single unit, typically eight bits

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Storage Capacities Kilobyte (KB) – one thousand bytes Megabytes (MB) – one million bytes Gigabytes (GB) – one billion bytes Terabytes (TB) – one trillion bytes Petabytes (PB) – one quadrillion bytes

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. ASCII Codes

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Binary Number System Definition: Number system used by computers to perform computations since it has only two digits

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Binary Number System

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Direct vs. Sequential Access Direct (or Random) Access – Each storage position has a unique address. Each storage position can be individually accessed without having to search through other storage positions. Sequential Access – Data are recorded one after another in a predetermined sequence. Locating an individual item of data requires searching the recorded data until the desired item is located.

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Direct vs. Sequential Access

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Semiconductor Memory Characteristics: Small Fast Shock Resistant Temperature Resistant Volatile – contents of memory is lost when power is interrupted Used for Primary Storage

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. RAM vs. ROM Random Access Memory (RAM) – each memory position can be both sensed and changed Read Only Memory (ROM) – can be read but not erased or overwritten

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Firmware Definition: Frequently used programs which are permanently burned into ROM during manufacture

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Magnetic Disks Characteristics: Fast Large Reasonably Priced Used for Secondary Storage

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Types of Magnetic Disks Floppy Disks – single disk inside a protective jacket Hard Disk Drives – several disks, access arms and read/write heads in a sealed module Redundant Arrays of Independent Disks (RAID) - disk arrays of interconnected microcomputer hard disk drives

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Formatting Disks

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Hard Disk Drives

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Magnetic Tape Definition: Read/write heads of magnetic tape drives record data in the form of magnetized spots on the iron oxide coating of the plastic tape

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Optical Disks

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Optical Disks

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. Summary Major types of computers include microcomputers, midrange computers, mainframe computers and supercomputers. A computer is a system of information processing components that perform input, processing, output, storage, and control functions.

Copyright © 2006, The McGraw-Hill Companies, Inc. All rights reserved. End of Chapter Chapter 3