Slide 1
Chapter
4
Computer Software
Well, Sort-of
Slide 2
Chapter
4
Computer Software
What is Software??
 Various kinds of programs used to operate computers and
related devices
How did it come about??
 The first software program was
actually written about 1833 by Ada
Augusta Lovelace (Lord Byron’s
Daughter)

We can skip forward to computer
programs, however
Slide 3
Chapter
4
Computer Software
 Programming Languages
 First Generation Languages (Machine Language)
 Suppose that I wanted to add two numbers together,
for example 2 + 3
• First, we would have to move the values into
two registers in the CPU’s Internal Storage
R1
R2
2
3
• Next I would have the ALU to add the contents of the
registers and store the result in Register 2 (maybe)
R2
5
(Well, Kind of – It’s a little more involved)
Slide 4
Chapter
4
Computer Software
 Programming Languages
 First Generation Languages (Machine Language)
 We Actually have to do a few things.
• First we have to find the operating code, or op code (by
number) to move the data (let’s assume the command is
number 28)
• Of course, we have know the identifying number for each
of the registers (assume R1 = 12; R2 = 13)
• Finally, we have to find the op code for addition
(Assume it is 37).
• The code I enter might be:
28 2 12;
(Well, Kind of – It’s a little more involved)
28 3 13;
37 12 13 13;
Slide 5
Chapter
4
Computer Software
 Programming Languages
 First Generation Languages (Machine Language)
 Let’s not forget that the computer is just a series of
light-switches (binary). Therefore we need to convert
our decimal values to binary:
2
3
12
13
28
37
= 000000000000010 (on 16-bits)
= 000000000000011 (on 16-bits)
= 00001100 (on 8-bits)
= 00001101 (on 8-bits)
= 00011100 (on 8-bits)
= 00100101 (on 8-bits)
Therefore, We
would enter the
commands:
00011100 000000000000010 00001100;
00011100 000000000000011 00001101;
00100101 00001100 00001101 00001101;
Slide 6
Chapter
4
Computer Software
 Programming Languages
 Second Generation Languages (Assembly – c1948)
 The advancement over machine level languages was
that it was mnemonic (assisting or intended to assist
the memory)
• We did not need to know the specific register
addresses
• We did not need to know the op codes
• For the previous example, the code we enter might be:
MOV 2 R1;
MOV 3 R2;
ADD R1 R2 R2;
 An Assembler would then transfer the commands
into a machine level language
Slide 7
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 The advancement over assembly level languages
was that programmers did not need to know either
the op codes nor the registers used
• Specific locations in RAM were referred to by a user
defined name
• The compiler or interpreter, as well as the operating
system, kept track of the specific locations
• For the previous example, the code we enter might be:
X = 2 + 3 (FORTRAN)
 The code would then be rewritten as either an
assembly language code or directly to a machine
level language
Slide 8
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 In the above example ‘X’ is a specific location in
RAM, although we don’t have to know where it is
• It is usually referred to as a variable
• Meaning that we can change the contents of the
location as we wish
• Although it can be a constant
• Meaning that once we set its value, it can not be
changed
 Either way, the address is assigned by the operating
system at run time and managed by the compiled
program (i.e., the machine-level program)
Slide 9
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 Third generation languages are Procedural in nature
• If, for example, we want to find the average age of
a class, we need to know the procedures involved
• We need to add every persons age in a class
together
• We then need to divide the sum of every persons age
by the number of people in the class
• The result is the average age of the class
 Third generation languages are also known as
structured programming
Slide 10
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 Third generation languages are also referred to as
‘High-level Languages’ (so are 4th generation
languages)
 Third generation languages (as well as 4th generation
languages) may be either interpreted or translated
languages (although they are generally translated)
What’s the difference??
Slide 11
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 Think of a person who works
at the United Nations
 As soon as these people get
a phrase of what a person is
talking about, they put it into
the language which they are
interpreting
 At the end of the day, they might not even know what
the speech was about
(That is not their job)
Slide 12
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 Now think of someone whose job is to
translate a book from one language to
another
• S/he will read the book many times
• S/he will try and find the best way to
say what the author was trying to say
(That IS their job)
What does this have to do with computers??
Slide 13
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 There are two classes of program languages
• Those that are interpreted
• BASIC started as an interpreted language
• Those that are translated or compiled
• The compiler makes a few ‘passes’ through the code
• It first checks syntax
• It next checks simple logic
• It sets-up variable tables
• The compiler creates a separate executable (.exe) or
command file (.com)
• These file are machine language files
Slide 14
Chapter
4
Computer Software
 Programming Languages
 Third Generation Languages (mid 1950’s)
 Third generation languages are also referred to as
‘High-level Languages’ (so are 4th generation
languages)
• If, for example, we want to find the average age of
a class, we need to know the procedures involved
• We need to add every persons age in a class
together
• We then need to divide the sum of every persons age
by the number of people in the class
• The result is the average age of the class
Slide 15
Chapter
4
Computer Software
 Programming Languages
 Fourth Generation Languages (4GLs)
 4GLs are non-procedural languages
• If, for example, we want to find the average age of
a class, we need to enter the command
Get Class Average
(or something similar)
• The procedures are built-into the commands
• These end result is still the creation of
machine language files
Slide 16
Chapter
4
Computer Software
 Programming Languages
 Fifth Generation Languages (5GLs)
 Maybe --- Someday
 The intention is have speech recognition Artificial
Intelligence (AI) programs that allow speech
recognition
• Sounds a little like a Star Trek episode
“Computer – Save the world”
Slide 17
Chapter
4
Computer Software
 Programming Languages
 Programming Tools
 Help programmers identify and minimize errors while
they program
 Provide a computer-aided programming environment
• Graphical Programming environments: Akin to
toolbars and menus
• Program Editors: Packages for source code
creation which check key words, structures as the
program is typed in
• Debuggers: a computer program that is used to
test and debug other programs.
Slide 18
Chapter
4
Computer Software
 Programming Languages
 Computer-Aided Software Engineering (CASE)
 Allow program development through the use of
system development models
• e.g., Entity Relationship Diagrams
• An ERD is a model for graphically showing the
contents of a database table and its relationships to
other tables
 Once the model has been constructed, the CASE
tool constructs the data dictionary and can create the
DBMS code (in SQL or any other language)
Slide 19
Chapter
4
Computer Software
 Programming Languages
 Web Languages
 Languages for building multi-media
web applications
 Hypertext Mark-up Languages
(HTML)
• Page description language that creates hypertext
and hypertext linkages
• Hyperlinks: allows control to be given to other parts
of a document or to any document on the WWW
• HTML can be created from various programs
(Word, Frontpage) without formal training in HTML
Slide 20
Chapter
4
Computer Software
 Programming Languages
 Web Languages
 eXtesible Markup Languages (XML)
• Describes the contents of webpages
by applying identifying tags
(contextual labels) to the data in web
documents
• Its primary purpose is to facilitate the sharing of
data across different information systems,
particularly systems connected via the Internet
• XML supports the automatic electronic exchange of
business data between companies and their
customers, vendors, suppliers and partners
Slide 21
Chapter
4
Computer Software
 Programming Languages
 Web Languages
 Java
• OOP language
• Consists of small applets that can
be connected and used on any
operating system
• Programmers are spared the burden of having to
perform manual memory management.
• Your On-line quizzes are Javascripts
Slide 22
Chapter
4
Computer Software
 Programming Languages
 Web Languages
 Java
• OOP language an object-oriented
programming language that is
simple, secure and platform
independent
• Consists of small applets that can be connected
and used on any operating system
• Programmers are spared the burden of having to
perform manual memory management.
• Your On-line quizzes are Javascripts
Slide 23
Chapter
4
Computer Software
 Programming Languages
 Object Oriented Programming (OOP)
 Sometimes also referred to as 5GLs (???)
 An object consists of data and procedures that can
be performed on the data
• C++
• Java
• Visual Basic
Slide 24
Chapter
4
Computer Software
 Programming Languages
Slide 25
Chapter
4
Computer Software
 Types of Software
End Users
Applications Software
System Software
Computer
Hardware
System Mgt & Development
General Purpose – Application Specific
Slide 26
Chapter
4
Computer Software
 Types of Software
Slide 27
Chapter
4
Computer Software
 Types of Software
These have
already been
covered
Computer
Software
Systems Management
Programs
System
Software
System
Management
Programs
System
Development
Programs
Slide 28
Chapter
4
Computer Software
 System Software
 Programs that manage the hardware, software,
network, and data resources of computer systems
Operating Systems
• An integrated system of programs that manages the
operations of the CPU, controls I/O, storage resources
and provides various support services as the computer
executes applications




UNIX
Windows/Vista
Linux
Mac OS X
Slide 29
Chapter
4
Computer Software
 System Software
Operating System Interfaces
The part of the OS that
allows communication
with it to load programs,
access files, and
accomplish other tasks
Types:
• Command-Driven
• Menu-Driven
• GUI
Slide 30
Chapter
4
Computer Software
 System Software
Operating System Functions
 Resource Management
• Programs to manage the hardware and networking resources
of a computer system, including its CPU, memory, secondary
storage devices, telecommunications processors, and
input/output peripherals
 Memory management programs keep track of where data
and programs are stored
 Swapping of programs of programs between RAM and
secondary storage
 Swapping allows for virtual memory whereby programs
can process more than RAM would normally allow
Slide 31
Chapter
4
Computer Software
 System Software
Operating System Functions
 File Management
• Programs to control the creation, deletion and access of
data and programs
 Keeping track of the physical location of files on
secondary storage
 Maintaining directories of information about the
location and characteristics of files stored on
secondary storage
Slide 32
Chapter
4
Computer Software
 System Software
Operating System Functions
 Task Management
• Managing the accomplishment of several programs
 Your text applies that multitasking and multiprogramming are the same (NOT):
 Multitasking: performing many applications at what
appears to be the same time (not possible if you
have you have only 1 CPU)
 Multiprocessing: performing many applications at
the same time (assumes that you have more than 1
CPU – but be careful: 2 processors does not imply
you can do twice the work of 1)
Slide 33
Chapter
4
Computer Software
 System Software
Operating System Functions
 Utilities: Consider those available in XP:
Slide 34
Chapter
4
Computer Software
 System Software
Operating System Functions
 Utilities: Consider those available in XP:
 Security Monitors: Monitor and control computer
usage, checking for unauthorized usage
 Character Map: Preferred Character set
 Disk Clean-up: Archiving/deleting infrequently used
programs/data
 Disk defragmenter: Putting fragmented files back
together so they con be collected faster
 Performance Monitors: Monitor and adjust the
performance of computer systems to keep them running
efficiently
Slide 35
Chapter
4
Computer Software
 System Software
Operating System Functions
 Other Systems Software
 Middleware: software that helps diverse software
applications and networked computer systems
exchange data and work together more efficiently
• Web Servers
• Enterprise Application Integration (EAI)
• Application Servers: Software which provides an
interface between an operating system and application
programs of users
Slide 36
Chapter
4
Computer Software
Operating Systems (A quick Aside)
 Linux
 created by Linus Torvalds in 1991
 includes system utilities & libraries
from the GNU Project
• The founding goal of the GNU project was, in the words of
its initial announcement, to develop "a sufficient body of
free software [...] to get along without any software that is
not free."
 Open Source Hardware:
• Free
• Stable
• Easily fixed if bugs appear
Slide 37
Chapter
4
Computer Software
Operating Systems
 Linux
Why did Linux become popular??
 Low-cost alternative in sagging economy
 Fear of Microsoft gaining a stranglehold on corporate
customers
 Intel loosened its relationship with Microsoft
 IBM made an effort to be Linux-compatible
Slide 38
Chapter
4
Computer Software
Operating Systems
 Linux
How is Linux doing??
 Linux runs almost 15% of all servers
 Growing at 23% per year
 Over 10% of IBM mainframe sales run Linux
 Only 1% of PCs use Linux but 30% of CIOs were
considering moving their companies’ PCs to Linux
Slide 39
Chapter
4
Computer Software
 Types of Software
Computer
Software
programs that perform
common information
processing jobs for
end users
Application
Software
General
Purpose
Applications
Application
Specific
Programs
Applications Software:
perform information
processing tasks for end
users
support specific
applications of end
users in business and
other fields
Slide 40
Chapter
4
Computer Software
 General-Purpose Application Software
 Software Suites: Several programs bundled together
•
•
•
•
Cheaper than cost of all individual programs
Use similar GUIs (Icons, menus, etc)
Share similar tools (spell checkers, wizards, hot keys)
Problem: Bloatware
Slide 41
Chapter
4
Computer Software
 General-Purpose Application Software
 Integrated Packages: Provides some of
the features of several programs in one
software package
• Omit some features found in software suites
• Cheaper
• Requires less storage
 Web Browsers: Software interface
used to point and click through the
hyperlinked resources of the Internet
• MS Explorer
• Netscape navigator (defunct)
• Mozilla Foxfire (freeware)
Slide 42
Chapter
4
Computer Software
 General-Purpose Application Software
 Electronic Mail: software used to send
and receive electronic messages and
file attachments via the Internet,
intranets or extranets
• MS Outlook, Yahoo!Mail, Gmail
 Instant Messaging: software used to
send and receive electronic messages
instantly to facilitate real time
communication and collaboration
• AOL Instant Messenger
• MSN Messenger
• Yahoo! Messenger
Slide 43
Chapter
4
Computer Software
 General-Purpose Application Software
 Word Processing: software that
supports the creation, editing, revision
and printing of documents
• Include features such as spellchecking,
thesaurus, and grammar correction
 Desktop Publication: software that
supports the production of materials
that look professionally published
• Professional quality publications which
integrate text and graphics
Slide 44
Chapter
4
Computer Software
 General-Purpose Application Software
 Electronic Spreadsheets: Software
that supports the development of
electronic worksheets consisting of
rows and columns used for business
analysis, planning and modeling
 Presentation Graphics: Software that
helps convert numeric data into
graphics displays and prepare
multimedia presentations including
graphics, photos, animation, and video
clips
Slide 45
Chapter
4
Computer Software
 General-Purpose Application Software
 Video Software: Software that
supports the development of full video,
usually along with text and audio
• It usually includes the ability to import
and export video, cut and paste sections
of a video clip, add special effects and
transitions
 Personal Information Manager
(PIM): Software for end user
productivity and collaboration
• Organizes data and retrieves
information in a variety of forms (e.g.,
calendar) and allows distribution to
others
Slide 46
Chapter
4
Computer Software
 General-Purpose Application Software
 Groupware: Software that helps
workgroups and teams work together
to accomplish group assignments
• Also called collaborative software
• Relies on the Internet, Intranets and
Extranets on a global scale by virtual
teams located anywhere in the world
• MS Word and MS Excel keep track of who made changes
to the documents
• Lotus Notes
• Microsoft Exchange
• Microsoft’s SharePoint and IBM’s Webshare allow quick
creation of websites to share information
Slide 47
Chapter
4
Computer Software
 Software Implementation
 Custom Software: software
applications that are developed within
an organization for use by that
organization
 Commercial Off-the-shelf (COTS)
Software: software that is developed
by a software developer with the
intention of selling the software in
multiple copies
Slide 48
Chapter
4
Computer Software
 Software Implementation
 Application Service Providers (ASP):
companies that own, operate, and
maintain application software and the
computer system resources required to
offer the use of the application software
for a fee as a service over the Internet
• Lower cost of initial investment
• Lower cost of operating and maintaining software
• Reduces the need for much of the IT Infrastructure
and IT Personnel
Slide 49
Chapter
4
Computer Software
 Software Implementation
 Software Licensing: Purchasing the
right to use specific software under the
terms of the software licensing
agreement
• Purchasing a piece of software
does NOT mean ownership; it is a
license to use the software
• Intended to protects the vendor’s intellectual property
right
• The license prohibits duplication or resale of multiple
copies of the software
Slide 50
Chapter
4
Computer Software
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