Transcript Software - Tonga Institute of Higher Education

Tonga Institute of Higher Education
IT 245
Management Information Systems
Lecture 5
Software
Application Software
&
System Software
Versatile Machine
• Computers have become the most
versatile machines man has ever created
• The reason is that software allows a
computer to perform an infinite variety of
tasks.
Computer Software
• When computers first started, software was
defined as anything that was not hardware;
anything that wasn’t real
• Some text book defines software:
– A set of instructions to be used in a computer to get a
certain result
• Example, Microsoft Word is called software, but
the document file that you create is not software.
That is data or a document file.
Types of Software
• “Application” software are programs that
the user runs. These could be Microsoft
Word, Excel, a video game, a DVD video
player
• “System Software” is the software that
runs the operating system. It includes all
the utilities and helper programs that run
the operating system
Computer Programs
• Programs are a set of detailed, step-bystep instructions that tell a computer how
to solve a problem or carry out a task
• Programs are written in a computer
language that the computer can
understand.
• Typical languages might be called C, C++,
Java
Computer Programs
Programming
languages use
different words and
ideas to tell a
computer what to
do
Let’s look at what
this program does
How software works (more)
• A CPU understands a special machine
language only
• Thus, when you write a program in C++,
Java, etc, it must be translated into this
special machine language
• A “compiler” will turn your programming
code into machine language so it will run
correctly
How software works
Code is converted from a high level language like
C++ into machine language so it can run on the computer
Interpreters
• Some programming languages, called
“scripting languages” don’t use compilers
• These use “interpreters”
• The difference is that to run the program,
you run the interpreter first, and tell the
interpreter to run your program (your script
that you made)
• Examples: JavaScript, Perl
Interpreters
• Interpreters are useful because they allow a
program to run on any type of computer
• When you compile a program, it changes into
the binary language that only works on one kind
of processor
• This means your program cannot run on a
computer with a different CPU or operating
system
• An interpreter will change the code automatically
to the right kind of machine language so that the
programmer only needs to write the program
once.
A running program
The steps to run a program
1.
2.
3.
4.
5.
6.
7.
Double click on a program to start
Your clicking opens a compiled executable file stored on the
hard drive
The instructions (code of the program) is loaded into RAM and
then sent to the CPU
The CPU will run the program and ask the user to do
something.
When you are done with the program, you close it and the
CPU stops executing the program
The program instructions are erased from the RAM
The CPU is ready for another program
Overview of Computer Software
Application Software
• End user applications
• Before we start lets look at an example of
the changing world of software in business
Software – Real Case 1
Program components of the top 4 software suites.
Trends in Computer Software
• Trends in software is toward multipurpose, web-enabled
expert-assisted packages with natural language and
graphical user interfaces.
Application Software for End Users
• Can be subdivided into two Categories
– General purpose Category
– Application Specific Category
Application Software for End Users
• Application Specific - are available to
support applications of end users in
business and other fields
– such as managerial, professional and
business uses
• such as transaction processing, decision support,
accounting, sales management, investment
analysis and electronic commerce
Application Software for End Users
• General Purpose – programs that
perform common information processing
jobs for end users. Such as word
processing program, spreadsheet
program, database program, graphic
programs which are popular with
microcomputer users for home, education,
business, scientific and many other
purpose.
Software Suites & Integrated Packages
• Software Suites – comes bundled together as one
software such as MS Office, Lotus Smart Suite etc.
• Integrated Packages – combines some of the
functions of several programs into one software
package, such as MS Works, Workplace etc.
– This have proven that they offer enough functions and
features for many computer users while providing some of
the advantages of software suites in a small package.
Other Software
• Web Browsers – powerful and featurerich sometime called universal client –
install on the workstations of all the clients
(users) in a client/server networks
throughout an enterprise.
• Electronic Mail.
• Word Processing
• Desktop Publishing
• Electronic Spreadsheets
Other Software
• Database Management
– Database Development – Define and organize
the content, relationships and structure of the
data needed to build a database
– Database interrogation – Access the data in a
database to display information in a variety of
formats,
– Database maintenance – Add, delete update
and correct data in a database.
– Application Development – Develop prototypes
of Web pages, queries, forms etc.
Other Software
• Presentation Graphics and Multimedia
• Personal Information Manager (PIM) – for
end user productivity and collaboration
• PDA personal digital Assistance
GroupWare
• Collaboration Software – software that
helps workgroups and teams of general
purpose application group assignment.
Business Software
• Some of the major application software categories in an EBusiness enterprise
System Software – Computer
System Management
• System software consist of programs that
manage and support a computer system.
• Try Software Case 2
System Application Interactions
System Application Interactions
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System Development Program
Operating System (OS)
User Interface
GUI
Command Driven menu
Operating Systems
• The system software acts as the master
controller for all that takes place on a computer
• Every type of computer has an operating system
that defines many operations
• Examples: How many programs can run at
once? What do the borders around programs
look like? Can the computer connect to the
internet?
OS
• The operating system will coordinate all activities
that occur in a computer
• If, for example, you want to print a document,
– 1. Tell your application to print
– 2. The application tells the operating system that it
wants to print
– 3. The OS talks to the printer device, and the
document gets printed
Basic Function of OS
OS and resources
• The operating system manages system
resources. A resource might be the CPU,
RAM, space on a hard drive
• The OS must ensure all programs can get
access to these resources when they need
to.
– What if two programs both want to print?
– The OS will manage the resource, decide
who prints first and make the other
program wait
The OS and Memory
• One of the most important jobs an OS has it to
manage memory (RAM).
• If more than one program is running, the two
programs are both using the RAM.
• How do we make sure that the programs don’t use
each other's memory??
• The operating system gives each program running
it’s own different “memory space.”
• Sometimes the OS makes mistakes (errors from
programmers) and programs will use memory from
another program. The computer usually will crash
when this happens!!
Internal OS
• Because different programs might need the
same resource (memory, printer, speakers), the
OS must decide when and how each gets its
turn
• It will use “buffers” and “queues” to accomplish
this.
• A buffer is like a line of things waiting to happen.
The OS can finish with one, and then take the
next in line
Buffer/Queue
Program 1
1st
Program 2
Program 3
2nd
3rd
OS and GUI
• An OS will also usually determine the “look
and feel” of a computer.
• With the graphical user interface (GUI) the
OS can change how menus, windows and
icons appear to the person using the
computer
GUI and Text interface. OS changes the way it looks
OS
• The operating system usually lives on the hard
drive because it takes up a lot of space.
• The most important part of the OS is the
“kernel.” The kernel accomplishes the most
important tasks, like managing files and using
memory.
• You can’t close or exit the kernel. It is always
running. It’s what makes your computer and
operating system run.
Types of OS
• Single User – Only allows one person to use a
computer at a time
• Multi-User – more than one person can execute
programs on the computer
• Multi-User don't mean many people can use the
same keyboard and monitor at the same time,
but instead there are ways, by using the
network, to run programs on the computer
More OS Categories
• Multi-tasking – this means the OS can run more
than one program at a time. All current
Operating Systems are multi-tasking and allow
you to do more than one thing at once.
• If you talk on a cell phone and drive at the same
time, you are multi-tasking (doing more than one
thing at a time). A computer is very good at this
More OS categories
• Server OS – this will run all the responsibilities of
a server. It is most useful if it runs a network
• The main difference between a server and a
regular computer is that a server runs certain
programs (called services) that provide things
for the client.
• Any computer can be turned into a server with
the proper programs.
• Desktop OS – used on client or desktop
machines.
Available Operating Systems
• Microsoft – DOS, Windows
3.1,Windows95, Windows98, Windows
2000, Windows XP
• Apple – Macintosh (latest called OSX)
• Linux – Redhat, Mandrake, Suse, Debian
• UNIX – SunOS
Comparison Popular OS
Application Software
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Applications let users accomplish tasks
Word Processing
Desktop Publishing
Web authoring software
Spreadsheets
Accounting, Mathematical, Statistics
software
Other System Program
• Network Management Program
• Database Management System
• Utilities and security programs
Data management software
• Data management software (databases) help
organize, sort, store, and update data.
• A “record” holds the data for a single entity.
– If we had a database for students, a single “record”
would save all the information about one student
• A “field” holds one item of data.
– The students name would be a field. So would his
age, or address
Databases
• Database Management Software (DBMS) – this
helps people sort through a lot of data. It is a
piece of software like MS Access or mySQL
• Most powerful DBMS use what is called a
“relational” database structure.
• “Relational” means that relationships can be
found and created between different sets of data.
– For example, you might have a set of data about
students and one about classes.
– If the class table saved who was in the class, you
could look up and see where that student lived, using
the student table. This is a relationship
DBMS
• So how do you use a DBMS?
• There are user interfaces that help
• The main way is through a programming
language called SQL (Structured query
language). A query is a question.
• Example: You could “query” a database of
students to find all students with the name Sione
– The SQL statement to do that would look like
– Select * from StudentInformation where
firstname=“Sione”
Other queries
• Some advanced databases use Natural Language
Queries.
• This means you could just enter:
– What students are named Sione?
• This would work the same as the SQL query
– select * from StudentInformation where name=“Sione”
Graphics Software
• Paint software – image editing (for fixing images)
• Photo editing software – can fix photos
• Drawing software – for making objects, boxes,
lines
• 3-D graphics
• CAD software (Computer Aided Design) – used
by people who make buildings, cars, anything
that needs to be designed before it is built.
• CAD software can make blueprints for designs
Music Software
• To hear music on your computer, you need a
music player (like windows media player or
winamp).
• These players can “decode” a specific format of
music into the kind needed for it to come out of
speakers.
• MP3 is a format of music. An MP3 player can
‘decode’ the mp3 format into one that you can
hear.
• There are other formats like WAV, Ogg Vorbis,
WMA
Software Installations
• To install software you
will need the
“distribution disks” either CDs or
floppies.
• Also you need to
make sure your
computer has enough
memory and is fast
enough to run the
software
• This is called “system
requirements”
Steps in Installing Software
1.
2.
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4.
5.
6.
Copy files from the disk (CD or floppy)
Uncompress files (they are compressed to save space)
Analyze computer to see if it meets system requirements
Identify where operating systems files are that the
program might need.
For example: A MP3 Player might need to know how to
use the OS to send sound to the speakers
Update system files like the windows registry. The
program might need to tell the OS something about itself
Move files into correct place
Uninstalling software
• To get rid of software that you don’t want anymore
first look for a uninstaller program that came with
the installation of the program.
• If there is not an uninstaller, go to the control
panels (on windows) and look for the icon that
says, Add/Remove Programs.
• If you just try to delete a program, there may be
many parts that are left over from the program that
will take up space if not removed
Uninstalling
What is the Windows Registry
• Microsoft computers use the “windows registry” to tie
all the pieces of the computer hardware, peripherals
and software together
• The registry keeps track of where certain things are
like printers, memory, scanners, software ‘modules’
and OS components
• It also keeps track of user settings, like desktop
pictures, installed programs and what programs will
run when the computer starts up
• It is a database of information for the Windows
operating system
Registry
Registry
Copyrights and Software
• Companies try very hard to stop people
from stealing software.
• It is difficult because of a computer's ability
to do many things
• Computers make it easy to copy and
duplicate anything, including software,
movies and music
Copyrights and Software
• Companies have tried aggressively to stop
“software pirating” but fail.
• It is said the computer industry loses over
12 billion US dollars a year
• Piracy is very bad especially in India,
China, and Eastern Europe where many
people are too poor to buy software
Copyrights and Software
• Not all software costs money
• Shareware – lets you try software for a
while, then asks you to pay for it to
continue
• Freeware – the software is totally free
Copyrights and Software
• People today are beginning to realize they do
not need to buy software and can use free
software
• This software is called “open-source” - because
all the code that people made is available to see
and change.
• “Closed-source” is what companies like
Microsoft use to hide their property so people
cannot change and use it improperly
Open Source
• Open source is mainly associated with Linux and
Unix, two types of operating systems
• The Linux operating system and all the
programs that can be used with it are free and
are open source
• If a program is open source and you don’t like
how it runs, you are free to change the code and
make the program do something else
Open Source
• Because open source allows everyone to
look at the code or programming, people
say it is more secure and more stable.
• Many people all over the world can look at
the software, instead of just a few people
inside a company.
Summary
• Operating systems
• Application Software
– Databases, Media players,
• Installing software
• The Window Registry
• Copyrights and Open Source