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Module 2

Computers and Their Business Applications

Learning Objectives (1 of 2)

Define a computer system, and describe its components

Discuss the history of computer hardware and software

Analyze the impact of the three factors distinguishing the computing power of computers

Summarize the three basic computer operations

Discuss the types of input, output, and memory devices

Learning Objectives (2 of 2)

Explain how computers are classified and their business applications

Apply knowledge of two major types of software and their use in a business setting

List the five generations of computer languages

Define object-oriented programming

Defining a Computer (1 of 3)

A computer is a machine that:

Accepts data as input

Processes data without human intervention using stored instructions

Outputs information

Instructions (i.e., a program) are:

Step-by-step directions for performing a specific task

Written in a language the computer can understand

Defining a Computer (2 of 3)

Garbage in, garbage out (GIGO)

If input data is erroneous, the information provided by the computer is also erroneous

Defining a Computer (3 of 3)

Writing a computer program

Identify what needs to be done

Plan a method to achieve the goal

Select the right language

Depends on the problem being solved and the type of computer being used

A program is also called the source code

Must be translated into object code, consisting of binary 0s and 1s

Computer understands 0s and 1s of binary code as on or off signals

Components of a Computer System (1 of 5)

Hardware components

Physical devices such as keyboards, monitors, and processing units

Software components

Programs written in computer languages

Components of a Computer System (2 of 5)

Central processing unit (CPU) is the heart of a computer; has two components:

Arithmetic logic unit (ALU): performs arithmetic operations (+, –, *, /) and comparison or relational operations (<, >, =)

Control unit: tells the computer what to do, such as instructing the computer which device to read or send output to

Components of a Computer System (3 of 5)

Computers can either have a single processor or multiprocessors

Multiprocessing: use of two or more CPUs in a single computer system

Exhibit 2.1 The Building Blocks of a Computer

Components of a Computer System (4 of 5)

Bus: link between devices connected to the computer

Parallel or serial

Internal (local) or external

Disk drive: peripheral device for recording, storing, and retrieving information

Components of a Computer System (5 of 5)

CPU case: enclosure containing the computer’s main components

Referred to as computer chassis or tower

Motherboard: main circuit board containing connectors for attaching additional boards

Usually contains CPU, basic input/output systems (BIOS), memory, storage, interfaces and expansion slots

Exhibit 2.2 Components of a Computer System

The History of Computer Hardware and Software

Major developments in hardware have taken place over the past 60 years

To make these developments more clear, computers are often categorized into “generations”

Table 2.1 Hardware Generations

Generation	Date	Major Technologies	Example
First	1946-1956	Vacuum tube	ENIAC
Second	1957-1963	Transistors	IBM 7094, 1401
Third	1964-1970	Integrated circuits, remote data entry, telecommunications	IBM 360, 370
Fourth	1971-1992	Miniaturization, VSLI, personal computers, optical disks	Cray XMP, Cray II
Fifth	1993-present	Parallel processing, gallium arsenide chips, optical technologies	IBM System zEnterprise EC12

The Power of Computers

Computers draw their power from three factors that far exceed human capacities

Speed

Accuracy

Storage and retrieval capabilities

Speed

Computer speed is measured as the number of instructions performed per fractions of a second

Millisecond: 1/1,000 of a second

Microsecond:1/1,000,000 of a second

Nanosecond:1/1,000,000,000 of a second

Picosecond:1/1,000,000,000,000 of a second

Accuracy

Degree of accuracy is critical in many computer applications

A small degree of inaccuracy could lead the space shuttle to land in Canada instead of the United States

Storage and Retrieval

Storage: saving data in computer memory

Retrieval: accessing data from memory

Data is stored in bits

American Standard Code for Information Interchange (ASCII)

Data code for text files, PC applications, and the Internet

Defines up to 128 characters

Table 2.3 Storage Measurements (Approximations)

Value	Size in Bytes
1 bit	A single value of 0 or 1
8 bits	1 byte or character
210 bytes	1,000 bytes, or 1 kilobyte (KB)
220 bytes	1,000,000 bytes, or 1 megabyte (MB)
230 bytes	1,000,000,000 bytes, or 1 gigabyte (GB)
240 bytes	1,000,000,000,000 bytes, or 1 terabyte (TB)
250 bytes	1,000,000,000,000,000 bytes, or 1 petabyte (PB)
260 bytes	1,000,000,000,000,000,000 bytes, or 1 exabyte (EB)

Computer Operations

Computer functions

Three basic tasks: arithmetic operations, logical operations, and storage and retrieval operations

Add, subtract, multiply, divide, and raise numbers to a power (exponentiation)

Perform comparison operations by comparing two numbers

Store massive amounts of data in very small spaces and locate a particular item quickly

Input, Output, and Memory Devices

To use a computer and process data, three major components are needed

Input

Output

Memory

Input Devices

Send data and information to the computer

Keyboard, mouse, touch screen, stylus, trackball, data tablet, barcode reader, optical character reader (OCR), magnetic ink character recognition (MICR) system, optical mark recognition (OMR) system, camera, microphone

Output Devices

Many output devices are available for both mainframes and personal computers

Display output in the forms of soft copy (screen) and hard copy (print)

CRT, LCD OLED displays

Inkjet, Laser printers

Other output devices include:

Plotters to convert output to graphics

Voice synthesizers convert output to voice

Memory Devices

Main memory

Stores data and information and is usually volatile

Contents are lost when electrical power is turned off

Secondary memory

Nonvolatile

Holds data when the computer is off or during course of a program's operation

Serves as archival storage

Main Memory Devices (1 of 2)

Semiconductor chips made of silicon

Can be volatile or nonvolatile

Random access memory (RAM)

Volatile memory, in which data can be read from and written to

Known as read-write memory

Cache RAM: stores recently accessed memory

Resides on the processor

Main Memory Devices (2 of 2)

Read-only memory (ROM)

Nonvolatile

Data cannot be written to it

Typically stores BIOS information and the computer system’s clock

Other types of ROM

Programmable read-only memory (PROM)

Erasable programmable read-only memory (EPROM)

Secondary Memory Devices (1 of 2)

Nonvolatile; used for storing large volumes of data for long periods

Magnetic disks

Made of Mylar or metal

Used for random-access processing

Magnetic tape

Made of a plastic material

Stores data sequentially; used for storing backups

Secondary Memory Devices (2 of 2)

Other devices include:

Hard disks

USB flash drives and memory cards

Solid-state drives (SSD)

Redundant array of independent disks (RAID) system

Collection of disk drives used for fault tolerance and improved performance

Found in large network systems

Cloud storage

Online storage involving multiple virtual servers that are hosted by third parties

Access data anytime, anywhere

Improved security and collaboration

Table 2.4 Capacity of Secondary Memory Devices

Device	Storage Capacity
Memory stick	1 TB
Hard disk	16 TB
SD Card	1 TB
SSD	60 TB

Storage Area Networks and Network-Attached Storage

Storage area network (SAN)

Dedicated high-speed network consisting of both hardware and software

Connect and manage shared storage devices

Disk arrays, tape libraries, and optical storage devices

Network-attached storage (NAS)

Network-connected computer dedicated to provide file-based data storage services to other network devices

Software on the NAS handles data storage, file access

Popular for Web servers and e-mail servers

Classes of Computers

Classified based on cost, amount of memory, speed, and sophistication

Computer classifications

Subnotebooks and notebooks

Personal and minicomputers

Mainframes

Supercomputers

Server Platforms: An Overview

Server: computer and all the software for managing network resources and offering services to a network

Available server platforms:

Application servers

Database servers

Disk servers

Fax servers

File servers

Mail servers

Print servers

Remote access servers (RAS)

Web servers

What is Software?

The programs that run a computer system

Classifications

System software: works in the background and takes care of tasks such as deleting unneeded files

Application software: performs specialized tasks

Operating System Software (1 of 2)

Set of programs for controlling and managing computer hardware and software

Provides an interface between a computer and the user

Increases computer efficiency by helping users share computer resources and performing repetitive tasks for users

Operating System Software (2 of 2)

Consists of control programs to manage hardware and resources by performing:

Job management

Resource allocation

Data management

Communication

Supervisor program (i.e., the kernel)

Responsible for controlling all other programs in the OS

Application Software

Commercial software or software developed in house; used to perform a variety of tasks on a personal computer

Word processing, spreadsheet, database, presentation, and graphics

Desktop publishing

Financial planning and accounting

Project management

Computer-aided design (CAD)

Computer Languages (1 of 4)

Machine language

First generation of computer languages

Consists of a series of 0s and 1s representing data or instructions

Dependent on the machine

Time-consuming to write a program

Computer Languages (2 of 4)

Assembly language

Second generation of computer languages

Higher-level language than machine language

Also machine dependent

Uses a series of short codes, or mnemonics, to represent data or instructions

Writing programs in assembly language is easier than in machine language

Computer Languages (3 of 4)

High-level languages

Third-generation of computer languages

Machine independent

Used for Web development and Internet applications

Self-documenting; easier to learn and code

Fourth-generation languages (4GLs)

Commands are powerful and easy to learn

Use macro codes that can take the place of several lines of programming

Computer Languages (4 of 4)

Fifth-generation languages (5GLs)

Use artificial intelligence technologies

Knowledge-based systems, natural language processing (NLP), visual programming, and a graphical approach to programming

Designed to facilitate natural conversations between an individual and the computer

Object-Oriented Programming: A Quick Overview (1 of 2)

Object-oriented programming (OOP) language

Organized around a system of objects that represent the real world as opposed to a series of computational steps used in traditional languages.

Two main parts: objects and classes

Objects

Items that contain both data and the procedures that read and manipulate it

Classes

Define the format of the object and the action it performs

Object-Oriented Programming: A Quick Overview (1 of 2)

Major advantages of OOP

Modularity

Written for specific and self-contained modules

Easier to write, modify, and troubleshoot than traditional codes

New features can be added as new modules without impacting existing modules

Reuse of codes for other purposes

Codes written for one object can be simply modified for another object

Effective problem solving

Can break down a program into small-sized problems

Can solve one module or one object at a time

Exhibit 2.4 Object-oriented Programming key principles

Summary (1 of 2)

A computer can have many definitions

Major developments in hardware have taken place over the past 60 years

Computers draw their power from speed, accuracy, and storage and retrieval capabilities

Computers perform arithmetic, logical, and storage and retrieval operations

Summary (2 of 2)

Computers are classified based on cost, amount of memory, speed, and sophistication

To process data, a computer requires input, output, and memory devices

Software is all the programs that run a computer system

System software

Application software

Computer languages include machine, assembly, high-level, fourth- and fifth- generation languages

OOP languages emphasize simplicity and adaptability