The document discusses real-time operating systems (RTOSes). It defines an RTOS as an operating system intended for applications that process data as it comes in without buffer delays. Examples provided of applications that use RTOSes include embedded systems, industrial robots, and scientific research equipment. The document outlines two basic RTOS designs: event-driven systems that switch tasks only when higher priority events need service, and time-sharing systems that switch tasks on a clock interrupt. Real-life examples of RTOSes mentioned include Windows CE, QNX, RT Linux, VxWorks, and Tron.

1. Operating System
Real Time Operating System
The real time operating system is an operating system that intended to
serve real time applications that process the data as it come in , typically
without buffer delays.
A Real Time Operating System is a multitasking operating system
designed for real time applications.
Examples of RTOS
Embedded System , Industrial Robots,Scientific Research Equipment etc.
Vision of RTOS
 An RTOS simplify the creation of real time application
 This requires a good devolopement of software
 An RTOS can respond more quickly and predictably to an event than
other operating system

2. There are two basic design for RTOS
• 1.Event driven:-Switch task only when an event of higher
priority needs services called pre-emptive priority.
• 2. Time Sharing Design:-Switch task on a clock interrupt , and
events called Round Robin
Real Life Example of RTOS:-
Windows CE
QNX
RT Linux
Vx Works
Tron

3. ACTIVE LINE
Time Sharing System:-
Time Sharing is a technique which enables many peoples ,located at various
terminals , to use a particular computer at same time.
Processors Time , Which is shared among multiple users simultaneously is
term as Time Sharing.
CPU
USER2
USER4
USER3
USER1

4. Security and Protection of OS
In OS, Computer Security and Mechanism provided by an OS must
address the Following:-
Confidentiality or privacy-The requirement that information
mentioned by computer system be accessible by authorized parties.
External Protection of OS-
• Unauthorized Access:-Mechanism assuring only authorized
individuals se classified materials
• Malicious-Modification or Destruction
• Accidental-Introduction to inconsistency
• Authentication-How do we know the user is who she say she is .Can
have passwords of Domains.

5. Protection of password : Issues Include:-
1.It is very easy to guess passwords since people use simple and easily remembered
words.
2.Need exists to change password continually.
3.Limiting number of tries before locking up.
4.Use the complex password atleast 15 character.
Here we represent the Secure Devolopement Life Cycle
Security
requirment
Security Design
Implementation
Testing of
Security
Operation and
Mentainence

6. Application Level
Operating System
Firmware:BIOS
Application Level Security:-
• App Protect
• App licensing-enabling new business models
Secure OS:-
• Windows 10 IoT Featuring :-Bitlocker and Device Guard
Secure/Trusted Boot:-
• Secure Firmware upgrade
• Preventing tempering of the system BIOS