Information
technology
Nasih a.kareem
muhammed
What is a computer?

Is Any device capable of processing information
to produce a desired result. No matter how
large or small they are, computers typically
perform their work in three well-defined steps:
(1) accepting input, (2) processing the input
according to predefined rules (programs), and
(3) producing output. There are several ways to
categorize computers, including class (ranging
from microcomputers to supercomputers),
generation (first through fifth generation), and
mode of processing (analog versus digital).
Ways to Categorize Computers



Class: Computers can be classified as mainframes, minicomputers,
microcomputers, or PDAs. All other things (for example, the age of the
machine) being equal, such a categorization provides some indication
of the computer’s speed, size, cost, and abilities.
Generation: First-generation computers of historic significance, such as
UNIVAC(Universal Automatic Calculator), introduced in the early 1950s,
were based on vacuum tubes. Second-generation computers,
appearing in the early 1960s, were those in which transistors replaced
vacuum tubes. Third-generation computers, dating from the 1960s, were
those in which integrated circuits replaced transistors. Fourth-generation
computers, appearing in the mid-1970s, are those, such as
microcomputers, in which large-scale integration (LSI) enabled
thousands of circuits to be incorporated on one chip. Fifth-generation
computers are expected to combine very-large-scale integration (VLSI)
with sophisticated approaches to computing, including artificial
intelligence and true distributed processing.
Mode of processing: Computers are either analog or digital. Analog
computers, generally used in scientific pursuits, represent values by
continuously variable signals that can have any of an infinite number of
values within a limited range at any particular time. Digital computers,
the type most people think of as computers, represent values by
discrete signals—the bits representing the binary digits 0 and 1.
Computer components
 Hardware
 Software
Hardware
 Hardware
:
The physical components of a
computer system, including any peripheral
equipment such as printers, modems, and
mouse devices.
Type of devices


Input devices.
Output devices.
Input devices
A

peripheral device whose purpose is to allow
the user to provide input to a computer
system.
Example:
Keyboard, mouse, scanner, joystick, TrackPoint,
.. etc
Output devices
A
piece of hardware that can be used for
receiving data from computer.

Example:
Printer, plotter, speaker … etc.
software
 Computer
programs; instructions that
make hardware work
 Two main types of software


System software (operating systems): which
controls the workings of the computer.
e.g. Windows, Linux, Unix ..etc.
Applications: such as word processing
programs, spreadsheets, and databases,
which perform the tasks for which people
use computers.
continue
 Two
additional categories, which are neither
system nor application software but contain
elements of both, are network software,
which enables groups of computers to
communicate, and language software,
which provides programmers use the tools
that they need to write programs.
File
A
file is the basic unit of storage that
enables a computer to distinguish one set
of information from another. A file is the
“glue” that binds a conglomeration of
instructions, numbers, words, or images
into a coherent unit that a user can
retrieve, change, delete, save, or send to
an output device.
Folder
a
container for programs and files in
graphical user interfaces, symbolized on
the screen by a graphical image (icon) of
a file folder. This container is called a
directory in other systems.
 subdirectory n. A directory (logical
grouping of related files) within another
directory. (folder in folder)
File path
 relative
path. A path that is implied by the
current working directory. if the full
pathname is not entered the current
working directory becomes the relative path
of the file referred to.
 absolute path. A path to a file that begins
with the drive identifier and root directory
ends with the complete file name.
C:\user\university\stage1\it.doc
File extensions
A
set of characters added to a filename that
serves to extend or clarify its meaning or to
identify a file as a member of a category. An
extension may be assigned by the user or by
a program.
Example of some extensions
extension
Purpose (related to)
.doc , .docx
document word processing
.xls , .xlsx
Excel (spread sheet)
.jpg , .gif , .png , .bmp
Image (picture)
.psd
Photo shop application
.txt , .rtf
Text plain (Notepad)
.avi , .mpeg, .mp4, .wmv
Video type file
.mp3, .wma
Sound type file
.exe , .com , .bat
Executable file
.zip , .rar , .7zp
Archive (compressed)file
.pdf
Book reader type of file
File property
A
detail about a file that helps identify it,
such as a descriptive title, the author
name, the subject, or a keyword that
identifies topics or other important
information in the file.
command-line interface
A
form of interface between the operating
system and the user in which the user types
commands, using a special command
language. Although systems with
command-line interfaces are usually
considered more difficult to learn and use
than those with graphical interfaces
graphical user interface
 visual
computer environment that
represents programs, files, and options
with graphical images, such as icons,
menus, and dialog boxes, on the screen.
The user can select and activate these
options by pointing and clicking with a
mouse or, often, with the keyboard.
Basic I/O routines (Function)
open( )
close( )
read( )
write( )
create( ) remove( )
 File



attribute
Read only
Hidden file
Compress file
right click on file/folder -> properties
Keyboard
 Alphanumeric
Keys: These keys are used for
entering letters and numbers.
 Special Keys: Keys such as Control (CTRL), SHIFT,
SPACEBAR, ALT, CAPS LOCK, and TAB are
special keys. These special keys perform special
functions depending on when and where they
are used.
 Punctuation Keys colon (:), semicolon (;),
question mark (?), single quotation marks (‘ ’),
and double quotation marks (“ ”).
 Command Keys: Keys such as INSERT (INS),
DELETE (DEL), and BACKSPACE are command
keys
Cont.
 Enter
key: accepting data
 Navigation Keys
 Function Keys: Keys labeled from F1 to F12 are
function keys. You use them to perform specific
functions. Their functions differ from program to
program. The function of the F1 key in most
programs is to access the help file associated
with a program
 Numeric Keypad
 Windows Key: It has the Microsoft Logo This key is
used to open the Start menu, or is used in
combination with a second key to perform
common Windows tasks.
Folder properties
open( )
close( )
read( )
write( )
create( ) remove( )
 Folder



attribute
Read only
Hidden file
Compress file: The process of reducing the size
of a file for transmission or storage
 Customize

Change folder icon and folder image
Desktop


The desktop is the primary user interface of a
computer. When you boot up your computer,
the desktop is displayed once the startup
process is complete.
Desktop includes:
the desktop background (or wallpaper)
 icons of files and folders
 Task bar : it is located at the bottom of the screen
by default.
Note: In Mac OS X, the desktop includes a menu
bar at the top of the screen.
 Notification Area
 Context Menu (Right click)

Right click (context menu)
 View

Size, arrange, view.
 Sort
by
 Refresh
 Paste
 Paste Shortcut
 New
 Folder synchronization
 Screen resolution
 Gadget
 Personalize
Shortcut
 icon
on the desktop that a user can
double-click to immediately access a
program, a text or data file, or a Web
page.
Notification area button
 Clock,
battery, network, Speaker, show
Desktop
Keyboard shortcut
Display Help
Copy the selected item
Cut the selected item
Paste the selected item
Undo an action
Redo an action
Delete the selected item and move it to the
Recycle Bin
Delete the selected item without moving it
Shift+Delete
to the Recycle Bin first
Rename the selected item
F2
Ctrl+Shift with an arrow key Select a block of text
Select more than one item in a window or
Shift with any arrow key
on the desktop, or select text within a
document
Select multiple individual items in a window
Ctrl with any arrow
or on the desktop
key+Spacebar
F1
Ctrl+C (or Ctrl+Insert)
Ctrl+X
Ctrl+V (or Shift+Insert)
Ctrl+Z
Ctrl+Y
Delete (or Ctrl+D)
Keyboard shortcut
Ctrl+A
F3
Alt+Enter
Alt+F4
Ctrl+F4
Alt+Tab
Ctrl+Alt+Tab
Ctrl+Mouse scroll wheel
Windows logo key +Tab
Ctrl+Windows logo
key +Tab
Alt+Esc
Select all items in a document or window
Search for a file or folder
Display properties for the selected item
Close the active item, or exit the active
program
Close the active document
Switch between open items
Use the arrow keys to switch between open
items
Change the size of icons on the desktop
Cycle through programs on the taskbar by
using Aero Flip 3-D
Use the arrow keys to cycle through
programs on the taskbar by using Aero Flip
3-D
Cycle through items in the order in which
they were opened
Keyboard shortcut Cont.
F4
Display the address bar list
in Windows Explorer
Ctrl+Esc
Open the Start menu
F10
Activate the menu bar in the active
program
Right Arrow
Open the next menu to the right, or open a
submenu
Left Arrow
Open the next menu to the left, or close a
submenu
F5 (or Ctrl+R)
Refresh the active window
Alt+Up Arrow
View the folder one level up
in Windows Explorer
Esc
Cancel the current task
Ctrl+Shift+Esc
Open Task Manager
Shift when you insert a CD Prevent the CD from automatically playing
Left Alt+Shift
Switch the input language when multiple
input languages are enabled
Security Windows 7
Action Center
Use Action Center to make sure your
firewall is on, your antivirus software is up to
date, and your is computer set to install updates
automatically.
Security Windows 7 cont.
Windows Defender
Use Windows Defender to help prevent
spyware and other potentially unwanted software
from being installed on your computer without
your knowledge.
Security Windows 7 cont.
User Account Control
User Account Control asks for your
permission before installing software or opening
certain kinds of programs that could potentially
harm your computer or make it vulnerable to
security threats.
Security Windows 7 cont.
Backup and Restore
It's important to back up your files and
settings regularly so that if you get a virus or
have any kind of hardware failure, you can
recover your files.
Security Windows 7 cont.
Windows Update
Set Windows Update to download and
install the latest updates for your computer
automatically.
Security Windows 7 cont.
Windows Firewall
Windows Firewall can help prevent
hackers and malicious software, such as viruses,
from gaining access to your computer through
the Internet.