Operating Systems Basics

Operating Systems
and Windows

What is an Operating System?

•The most important
program that runs on your
computer. It manages all
other programs on the
machine.

•Every PC has to have one to
run other applications or
programs. It’s the first thing
“loaded”.

Operating System
•It performs basic tasks,
such as:

•Recognizing input from the
keyboard or mouse,

•Sending output to the
monitor,

Operating System

•Keeping track of
files and directories
on the disk, and

•Controlling
peripheral devices
such as disk drives
and printers.

Is There More Than One Type of OS?
•Generally, there are four types,
based on the type of computer
they control and the sort of
applications they support.

1.Single-user, single
task

This type manages the
computer so that one user
can effectively do one
thing at a time.

Types of Operating Systems
2. Multi-user, multi-task

Allows two or more users to run
programs at the same time. Some
operating systems permit hundreds or
even thousands of concurrent users.

3. Real Time Operating Systems

RTOS are used to control machinery,
scientific instruments, and industrial
systems.

There is typically very little user-
interface capability.

Resources are managed so that a
particular operation executes
precisely the same every time.


4. Single-user, Multi-tasking
This is the type of operating system most
desktops and laptops use today.
Microsoft’s Windows and Apple’s MacOS are
both examples of operating systems that will
let a single user have several programs in
operation at the same time.

OS’s Manage Applications
•Operating systems provide
a software platform on top
of which other “application”
programs can run.

•The application programs
must be written to run on a
particular operating system.

•So, your choice of operating
system determines what
application software you can
run.

Operating System Functions

•Besides managing
hardware and software
resources on the system,
the OS must manage
resources and memory.

•There are two broad
tasks to be accomplished.

OS - Memory Storage and Management
1. Each process must have
enough memory in which
to execute, and

It can neither run into the
memory space of another
process,

Nor be run into by another
process.

OS - Memory Storage and Management

1. The different types of memory
in the system must be used
properly so that each process
can run most effectively.

Cache Memory
•Cache - A section of a
computer's memory
which temporarily
retains recently
accessed data in order
to speed up repeated
access to the same data.
• It provides rapid
access without having
to wait for systems to
load.

RAM Memory
•Random access
memory (RAM) is the
best known form of
computer memory.

• RAM is considered
"random access" because
you can access any memory
cell directly if you know the
row and column that
intersect at that cell.

RAM Memory
• The more RAM your computer has,
the faster programs can function.
The two main types are called
DRAM and SRAM. SRAM is faster
than DRAM, but, more expensive.

Remember, that if the power is turned off,
then all data left in RAM, that has not been
saved to the hard drive, is lost.

Virtual Memory
•Virtual Memory – a method of using
hard disk space to provide extra
memory. It simulates additional RAM.

•In Windows, the
amount of virtual
memory available,
equals the amount of
free RAM plus the
amount of disk space
allocated to the swap
file.

Virtual Memory – Swap File

A swap file is an area of your hard disk that is
set aside for virtual memory. Swap files can be
either temporary or permanent.

OS - Wake up call

•When you turn on the power to
a PC, the first program that runs
is a set of instructions kept in
the computer's read-only
memory (ROM).

OS - Wake up Call

•It checks to make sure
everything is functioning
properly.

•It checks the CPU, memory,
and basic input-output
systems (BIOS) for errors.

OS – Wake up Call

•Once successful, the
software will begin to
activate the computer's
disk drives.

•It then finds the first piece
of the operating system:
the bootstrap loader.

OS - Booting the PC
•The bootstrap loader is a
small program that has a
single function: It loads the
operating system into
memory and allows it to
begin operation.

OS - Booting the PC
•The bootstrap loader sets up the
small driver programs that
interface with and control the
various hardware.

•It sets up the divisions of
• memory
• user information, and
• applications.

OS - Booting the PC
•It establishes the data
structures needed to
communicate within
and between the
subsystems and
applications of the
computer.

•Then it turns control of
the computer over to
the operating system.

Windows Desktop

Your Desktop may
look like this…

Windows Desktop

…Or like this.

How Do I Tell The OS What I Want To Do?

•You must continue to give
the operating system
commands that are accepted
and executed.
•The first command was
pushing the “ON” button which
started the “boot” process.

Enter Commands

•Commands can be
entered several ways:
•Through a keyboard.
•Pointing or clicking on
an object with a mouse.
(Graphical User Interface or GUI)

•Sending a command
from another program.

Windows and Mac are GUI’s

•Microsoft Windows and Apple Macintosh
operating systems are “graphical user
interfaces” or GUI’s.

GUI is defined as: A picture used in place of
a word or words to issue commands.

GUI – Standards

• GUI interfaces have standards that
are usually the same or similar in all
systems and applications.

• Standards apply to:
• Pointers and pointing devices
• Icons, desktops, windows and menus

Windows - GUI Pointers
•GUI uses pictures, symbols, or icons rather
than words to represent some object or
function. For example:
•A pointer or mouse pointer is a
small arrow or other symbol that
moves on the screen as you move
a mouse.

• An I-Beam pointer is used by many
desktop publishing systems and word
processors to mark blocks of text and
move the insertion point.

GUI – Cursors / Pointers
•The term
“cursor” typically
is used to show
where your typing
will appear.
Otherwise, the
term “pointer” is
the better choice.

Windows - GUI Icons
• Icon - A small picture that represents a
command, object, file, or window.

•Point and click with a mouse to execute a
command or convert the icon into a window.

•Icons are moveable around the display
screen, just like moving things around on
your desk.

Object Icons & Shortcut Icons
•You can create
•One type of and use a
icon is an shortcut icon to
object icon. open any
It allows application
you to open quickly. You
applications don’t have to
and use the Start
documents Menu to access
on your PC. a program or
document.

Windows - GUI Windows & Desktop
• You can divide the screen into
different areas.
• In each window, you can run a
different program or display a
different file.
• You can move windows around the
display screen, and change their
shape and size at will.

Windows - GUI Menus
•Menu - is an on-screen list
of options for using a
program. It can also be a
list of categories with many
other menu options under
it. Menus can "pop up" or
"pull down."

GUI – Share Data
•Because the formats are well-defined,
different programs that run under a common
GUI can share data. This makes it possible,
for example, to copy a graph created by a
spreadsheet program into a document
created by a word processor.

Windows - Taskbar
•Taskbar – shows you the windows
or programs that are currently open
on the desktop. You can switch
between windows by clicking on the
applicable button.

Windows – System Tray
•System Tray – shows you running
programs that were started
automatically by the operating
system, like anti-virus programs, the
clock and volume controls. These
programs are running in the
background.

Windows - Quick Launch Toolbar

•Quick Launch Toolbar – contains
one-click buttons, or shortcuts,
which open programs. You can
customize this toolbar however you
like.

Start Button

•The start button allows you to easily
access your computer programs or
configure Windows. By default the
start button is located at the bottom
left side of the screen.

Title Bar

•At the top edge of the window, inside
its border, is the title bar which extends
across the width of the window. It
contains the title of the application or
document.

•A small icon in the far left corner of
the title bar represents the object being
viewed in the window.

Minimize, Maximize and Resize Windows

•The title bar contains three little
buttons in the upper right-corner of the
window and are used to manage the
window size or close it altogether.

Minimize - Maximize
•The first button is the minimize
button and it will hide the window.
The window can be opened again
by clicking its button on the
taskbar.

•The second button is maximize,
which makes the window take
up all the screen space. Clicking
again turns the window back to
the size it was. The double-box
image is known as the restore
button.

Close Window

•The last button will
close a window. If it is
the last window of a
certain type of
program, it will exit or
quit that program.

Move a Window
•You can move a window to any
location on the desktop by “clicking
and dragging” the title bar with your
mouse.
•This is also referred to as
“drag and drop”.

•You can also
drag and drop
icons to move
the location of
files or shortcuts.

Menu Bar

•Menu bar - The horizontal bar near the
top of a window that displays the
names of menus from which you can
access features and perform tasks for
the current application.

Types of Menu Items

• Arrow: another menu
will cascade from it.

• Three dots: a dialog
box will open,
containing choices
for you to make.

Types of Menu Items
•Checkmark:
clicking this item
will toggle the
feature on or off.

•If a keyboard
shortcut is shown in
the menu, you can
use those keys to
run the command
without having to
open the menu.

Scroll Bar

•Scroll bar - the narrow
rectangular bar at the far
right of windows.
•Clicking on the up or down
arrow enables you to move
up and down through a
document.
• A movable square
indicates your location in
the document.

Windows Frame & Resizing
•You can also resize a
window by a click and
drag move.

Put the mouse cursor on the
edge of a window (that is not
maximized) and when the
pointer changes to a double
arrow, click and drag for the
new size. Some windows
have a handle on them for
resizing.

Status Bar

•Status bar – is located at the
bottom of a window and contains
information about formatting
options, errors, prompts,
messages, or the status of an
application.

Dialog Boxes

1. List box
2. Spin control box
3. Slide
4. Drop-down list
5. Radio button
6. Checkbox
7. Text box

Windows – Start Menu
• Start Menu – gives you access to all
programs and functions on your PC,
including “help” files and “search”
capabilities.

Windows HELP
•Access Windows 95 HELP menu
Windows
HELP through
the Start
menu.

Windows HELP
Windows 98 HELP menu

Windows HELP
•Windows XP HELP menu

Windows System Programs
•Windows has a number of internal
programs as part of the operating system
that help keep you organized and your
PC healthy.

•Here are a few:

Windows - My Computer

Al
s
the o k
Ex Wi now
plo nd n a
rer ows s

•My Computer – inside this icon you can find every
folder and file that your PC has access to.

Windows – Recycle Bin
•Recycle Bin – Deleted files and folders go here
first, where they wait to be permanently deleted
by you, or by rules that you set up. This is a
temporary storage area on your hard drive.

Windows – My Docs

•My Documents – a place to store
the documents and files you
create. Clicking on this opens an
explorer window displaying the
detail.

•It’s wise to keep the files you
create separate from the program
files, so when you backup your
data, it’s all located in one
location. You can then backup
just this area of your storage.

My Documents – Explorer Window

Windows – Network Neighborhood

•Network Neighborhood –
serves as a window into the
network resources you have
on your PC.

•If you are connected to a
network you will see all
the other PC’s linked to
your network and you can
share files, printers or
other hardware.

Logoff
•If your have multiple users on a PC
with separate “profiles” or user
logons, use the logoff process to
close out of your profile or to
switch users.

Shutdown Windows
•There is a “graceful” way of
shutting down your PC that will
save your program settings and
files.
•This shutdown process basically puts
the operating system to bed.

Which Explorer?
•Tip: Don't confuse Windows Explorer
with Internet Explorer.

•Windows Explorer is the
program that lets you explore
things "inside" your own
computer.

•Internet Explorer lets you
explore things "outside" your
computer -- namely things on the
Internet.

Operating Systems Basics

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