2. WHAT IS AN OPERATING SYSTEM?
The operating system is the most important program that
runs on a computer. Every general-purpose computer must have
an operating system to run other programs. Operating systems
perform basic tasks, such as recognizing input from
the keyboard, sending output to the display screen, keeping
track of files and directories on the disk, and
controlling peripheral devices such as disk drives and printers.
An interface between users and hardware - an environment
"architecture
For large systems, the operating system has even greater
responsibilities and powers. It is like a traffic cop -- it makes sure
that different programs and users running at the same time do
not interfere with each other. The operating system is also
responsible for security, ensuring that unauthorized users do
not access the system.
3. Need of Operating System
In earlier day’s user had to design the application
according to the internal structure of the hardware.
Operating System was needed to enable the user to
design the application without concerning the details
of the computer’s internal structure. In general the
boundary between the hardware & software is
transparent to the user.
4. Usage of Operating System
Easy interaction between the human & computer.
Starting computer operation automatically when
power in turned on.
Loading & scheduling users program.
Controlling input & output.
Controlling program execution.
Managing use of main memory.
Providing security to users program.
5. Starting up an operating system:
• Read boot strap program from ROM:
==> enables access to floppy and hard drives.
==>look for the core OS
(DOS: COMMAND.COM )
• Load the core OS into RAM.
• Run a sequence of jobs in batch mode.
7. Classification of operation systems
Multi-user: Allows two or more users to run programs
at the same time. Some operating systems permit
hundreds or even thousands of concurrent users.
Multiprocessing : Supports running a program on more
than one CPU.
Multitasking : Allows more than one program to run
concurrently.
Multithreading : Allows different parts of a single
program to run concurrently.
Real time: Responds to input instantly. General-
purpose operating systems, such as DOS and UNIX,
are not real-time.
-hard real time system
-soft real time system
CLASSIFICATION OF OPERATION SYSTEMS
8. Storage Hierarchy
Fast and Expensive
Slow an Cheap
Very fast storage is very
expensive. So the Operating
System manages a hierarchy of
storage devices in order to make
the best use of resources.
9.
10. advantages of windows
Language support.
Ease of use
Word processors
Backup and restore.
Accessibility
Encryption
Device management
Sticky notes
Internet games
Security features.
11. disadvantages of windows
Price: Microsoft windows is costly compared to
Linux
Security: When compared to linux it is much more
prone to viruses and other attacks.
Reliability: It needs to be rebooted periodically
else there is a possibility of hang up of the
system.
Software Cost: Even though the windows have
softwares, games for free most of the programs
will cost more than 200$.
13. ADVANTAGES OF LINUX
OS is a free of Cost
Security
Choice (Freedom)
Software
LINUX IS VERY STABLE
Reliable
Extremely powerful
14. Disadvantages of Linux
Understanding
Compatibility
Alternative Programs
Linux does not run most commercial software
Less off-line help is available for Linux
Some re-training can be required
Linux does currently not play Blu-ray discs
Not all hardware is supported
15.
16. Advantages Android
Multitasking:
Easy access to thousands of applications via the
Google Android Android App Market
Can install a modified ROM
Phone options are diverse
Ease of notification
Widget
OS Updates
Cost Effective
17. Disadvantages of Android
Hardware
Need internet connection
Wasteful Battery
Many applications contain virus
Continuous Internet connection
Application Quality
Advertise