MIS 1a Chapter 1

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Chapter 1 The Basics of Computing

• What is a Computer
• Types of Computers
• Computer Hardware
• Computer Software
• Communication Networks

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What is a Computer?
A computer is a device that accepts input,
manipulates it under a sequence of instructions
(a program) and produces an output. This process
is called the Information Processing
Cycle. The output can be the result of a
calculation or just an acknowledgement of the
input.
Processing Instructions
Input
Output
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For example an abacus is a kind of computer
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so is a Slide Rule
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and a Burroughs Adding Machine
Advertisement from 1954
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Handheld devices such as these are also computers
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• However, were concerned with just 3 types of
  computers that are used for business information
  systems
• Mainframes
• Minicomputers
• Microcomputers

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Mainframe Computers

• industry term for a large computer
• big iron
• modularized to reduce overhead
• used in centralized computing environments
• large-scale computing server
• high volume
• high overhead processing
• used as large database servers

Mainframes typically cost hundreds of thousands
of dollars and are manufactured by companies such
as Hitachi, IBM and Amdahl.
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Diagram of a Simple Mainframe Configuration
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Minicomputers

• smaller than a Mainframe
• larger than a PC (Microcomputer)
• have become the mid-range server
• IBMs AS/400 is an example

IBM AS/400
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Microcomputers

• Personal Computers (PCs)
• desktop computing and client-server
  applications
• can serve both as a client and a server
• are generally categorized by the CPU type
• Intel IBM compatible
• Motorola Apple / MacIntosh / Power PC
• Sun - SPARC

Microcomputers are what we think of as PCs.
Although they cross the line at times, Sun
Microsystems generally is thought to manufacture
high-end PCs.
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Basic Parts of a PC
Monitor
Computer Case
Keyboard
Mouse
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Components of a Computer

• A computer needs the following devices to
  function
• Input device(s)
• Processing Unit
• Output device(s)
• Storage device(s)

This is the computers hardwareit is tangible.
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Input Devices
Accept data for the computer to work with

• Keyboard
• Mouse
• Scanner
• Microphone

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Processing Unit
The Central Processing Unit, or CPU, is the
brains of the computer. It controls all activity
and performs operations on data based on its
instruction set. The CPU is made up of several
major units as diagrammed below.
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Processing Unit

• The CPU consists of these main elements
• Control Unit - executes the instructions as
  interpreted
• Arithmetic / Logic Unit - performs mathematical
  and
• logical operations
• Registers - serve as the short term memory for
• the ALUs computations and provides some
• reserved space for certain functions
• Clock Unit - generates pulses that determine the
  
• speed of instruction processing, the rate is
  measured in megahertz (Mhz)

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Processing Unit

• The CPU has two main features
• Its speed measured in millions of instructions
  per
• second, or MIPS
• Its word size is the number of bits the CPU can
• process at a time. An 32-bit processor
  manipulates 32 bits simultaneously.

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System Memory

• A PC has three basic types of memory
• Cache memory that is built into the CPU (not the
  CPU registers) called L1 or L2 cache
• Read Only Memory (ROM) that is used to boot
  the system (among other applications)
• Random Access Memory (RAM) which is the main
• memory that acts like the workshop or desktop
  of the CPU

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Output Devices

• The purpose of an output device is to present
• electronic data (and the results of our work) in
  a
• form that can be understood and used. For
• example, think how hard it would be to use a
• computer without a monitor.
• Typical output devices on a PC are
• Monitor
• Printer or Plotter
• Speakers

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Output Devices

• Monitors
• CRT Cathode Ray Tube, like a Television
• LCD Liquid Crystal Display
• TFT Thin-Film Transistor
• Printers
• Laser printers
• Inkjet
• Thermal Wax
• Dot-Matrix

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Auxiliary Storage Devices
These devices, also known as secondary storage,
are where the PC stores data that must last from
session to session. Basically speaking this is
the permanent data storage. Though they differ
in their technologies and methods of storage,
the result is the same the PC can easily
retrieve the stored data for use at a later
time. These components are many times referred
to as Mass Storage devices.
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Auxiliary Storage Devices

• Types of Auxiliary or Mass Storage devices are
• Floppy disk drive
• Hard disk drive
• Optical disks (Compact discs, DVD)
• Zip drives
• Jazz or Bernoulli drives
• Tape drives
• Flash memory

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Computer Software
Software is computer instructions (Programs) and
data. Anything that is electronically stored
on a computer storage device is considered
software. It is intangible and exists only
electronically.

• Two general types of software
• System software
• Application software

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System Software
Systems software are the programs that
control the computer and manage its resources.
Such as operating systems and system utilities.
Operating systems perform the basic tasks of
computing like managing the input and output of
data and interpreting the instructions of the
programs. System Utility software performs more
basic functions such as file management or
backup, but they must work under an operating
system.
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The Operating system connects components and
directs the flow of data.
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System Software

• Examples of Operating systems
• Windows (XP, 2000, ME, 98, 95, 3.1, CE)
• DOS (MS-DOS, DR-DOS, PC-DOS)
• Mac OS X
• Unix (Solaris, FreeBSD, SCO UNIX)
• Linux
• Palm OS
• BeOS

Operating systems are written to run on specific
processors (platforms).
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System Software

• Examples of Utility software
• Anti-virus software
• Norton, McAfee, Sophos, Trend Micro
• File Management
• PKZip, WinZip, Norton SystemWorks
• Disk Utilities
• PartitionMagic, System Commander
• Backup
• Retrospect, Backup MyPC

Utility software is written to run under specific
operating systems.
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Application Software
Application software consists of programs that
help you work and play on the computer. This
category includes word processors, games,
spreadsheets, drawing and other
productivity programs. This is the bulk of
all software written.
Application software is written to run under
specific operating systems.
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Application Software

• Examples of Application software
• Document Processing
• Adobe Acrobat, WordPro, TextBridge
• Graphics
• Flash, CorelDraw, PaintShop Pro
• Games
• MS Flight Simulator, Tomb Raider
• Programming
• Kylix, CodeWarrior
• Suites
• StarOffice, WordPerfect Office, Office 2000
• Database Management
• Oracle, SQL Server, MySQL

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Communication Networks aka Computer Networks
Two or more computers connected to share data and
resources are networked. The simple idea
behind computer networking is to allow users to
access more information and give them access to
devices not directly attached to their local
system, such as printers or storage devices.
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Computer Networks

• Two of the main types of computer networks are
• LAN - Local Area Network
• WAN - Wide Area Network
• A LAN is comprised of computers located within
• close proximity, such as in an office or
  building.
• A WAN is a network of computers that are situated
  
• further apart, but still connected. Such a
  network
• might be of computers within a single state
  agency
• or of a multi-national corporation worldwide.

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Computer Networks
A PC must have a Network Interface Card installed
to connect it to a network. The cards,
frequently called nics, come installed in many
new computers as they are also used for cable
modem and DSL internet service. The computers
can be configured in several ways, the most
popular of these architectures are
peer-to-peer and client/server. The first is a
loose connection of local computers with no
central authority, the later relies on a
server to manage the network and its resources.
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A peer-to-peer network requires the computers to
be connected to each other by a network cable,
usually an unshielded twisted pair cable known
as CAT 5. Connecting more then two computers
require the use of a network hub as shown.
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A client/server network uses a computer known as
the server to manage the network and control
access to resources. The computers can be
connected using various types of cable including
CAT 5, coaxial and fiber optical.
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Computer Networks

• Local Area Networks are configured in 3 basic
• topologies. These are either the logical or
• physical way the computers are connected. Each
• connection on the network is known as a node.
• These topologies are
• Star
• Bus
• Ring

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A Star topology connects all the nodes directly
to the server or to a connecting device such as
a hub.
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All nodes on a Bus topology are connected to
a central line or backbone.
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Nodes on a Ring topology are connected in a
closed loop. This means that each node has two
connections, one in and another out. Using this
type of topology the data must travel through
all the nodes.
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Computer Network Software

• Computer networks use special operating systems
• and other system software to manage the network,
• its resources and its users. Network Operating
• Systems (NOS) should be very secure and robust
• to provide reliable network services.
• Examples of such software are
• Windows 2000 Server
• Novell NetWare
• Unixtoo many flavors to link them all
• Linux

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The Internet
The Internet is a worldwide computer
network. Actually it is a loose collection of
networks. There is no central control or
authority, all cooperation is voluntary to a
degree Users access the Internet by using a
network that is connected to a backbone
usually through an Internet Service Provider
(ISP). The real access path to the net is
through a Network Access Point (NAP).
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The World Wide Web
The World Wide Web is a collection of computers
connected via the Internet that support the use
of documents written in HyperText Markup
Language (HTML). The web uses the HyperText
Transfer Protocol (HTTP) as the standard for the
formatting and transmission of these
documents. Not every server on the net uses
HTTP, and therefore is not part of the Web.
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• The Internet is very large and diverse, there is
  no
• one method of access and there are many protocols
• used such as
• NNTP - Network News Transfer Protocol for
• newsgroups
• SMTP - Simple Mail Transfer Protocol for sending
  
• e-mail
• FTP - File Transfer Protocol used for sending
  files
• Its a wonder it works so well, much less at all.

Hobbes' Internet Timeline http//info.isoc.org/gu
est/zakon/Internet/History/HIT.html