Transcript IT 141 – Information Systems 1

Lecture 05:
Computer Operations
and
Data Retrieval
Objectives
 Retrieve, view and closed a Word Processing
 Create, save and print a word processed document
 Retrieve, view and closed a Spreadsheet
 Retrieve, view and closed a Graphic file
 Retrieve, view and closed a Database.
Topics
 Software Basics
 Operating systems
 Types of software
 Software Installation
 Copyright laws
Introduction
 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
 The US government 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.
NOT EXAMINED
Computer Programs
 Programs are a set of detailed, step-by-step
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 [NOT EXAMINED]
Programming
languages use
different words and
ideas to tell a
computer what to
do
Let’s look at what
this program does
NOT EXAMINED
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
NOT EXAMINED
How software works
Code is converted from a high level language like
C++ into machine language so it can run on the computer
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
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
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
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
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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.
 NOT EXAMINED
 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, Window
Vista,
 Apple – Macintosh (latest called OSX)
 Linux – Redhat, Mandrake, Suse, Debian
 UNIX – SunOS
Application Software
 Applications let users accomplish tasks
 Word Processing - MSWord
 Spreadsheets - Excel
 Presentation – PowerPoint
 Database - Access
 Desktop Publishing - Publisher
 Accounting, Mathematical, Statistics software
 Web authoring software
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
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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.
3.
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
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.
Environmental Problem
 Power Surges
 when something boosts the electrical charge at some
point in the power lines which increase the electrical
potential energy
 Courses
 Lightning
 High-power electrical devices
 Faulty wiring
 How Surge Protectors Work
 When to Use a Surge Protector
Environmental Problem
 How Surge Protectors Work
 Protect electronic devices from surges.
 If the voltage from the outlet surges or spikes -- rises
above the accepted level -- the surge protector diverts
the extra electricity into the outlet's grounding wire.
 When to Use a Surge Protector
 Surge protector depends on what sort of device being
hooking up to power supply
Environmental Problem
 Blackout
 An accidental loss of electric power
 Effect – total cut out, - unexpected increases
 Avoid – using UPS – Uninterrupted Power Supply
Summary
 Operating systems
 Application Software
 Word Processor, Spreadsheet, Databases, Media players,
 Installing software
 Copyrights and Open Source
 Environmental Problems