OPERATING SYSTEM(17512) SESSION : COURSE : COMPUTER TECHNOLOGY SEMESTER : FIFTH SUBJECT CODE : FACULTY : PANKAJ G. INGOLE DEPARTMENT OF CM GHRP, NAGPUR

TEACHING AND EXAMINATION SCHEME Teaching SchemeExamination Scheme THTUPRPAPER HRS THPRORTWTOTA L NOTE : Two Class tests each of 25 Marks ( PTT – I & PTT – II ) Unit tests ( Chapter wise ) Assignments ( Chapter wise ) SYLLABUS

REFERENCE BOOK Text book for Theory : Operating System Concepts – Eighth Edition Silberschatz and Galvin, Addison-Wesley Inc. Reference book for Practical : Unix Concepts and programming Sumitabha Das, Tata McGraw Hill

UNIT I CONTENTSLECTURESMARKS Introduction: Objectives: Distinguish between various generation of computer. Classify different types of operating system. 1.1 Operating System - Evaluation, Generations 1st, 2nd, 3rd 1.2 Different Types of Operating systems- Batch operating system, Multi Programmed, Multitasking, Time Shared OS. Multiprocessor Systems, Distributed Systems, Cluster Systems, Real time systems. 4 12

LECTURE 1 & 2 UNIT 1

LECTURE I & 2 : CHAPTER I TOPICS Operating System – Evaluation Generations of operating System – 1 st, 2 nd, 3 rd

What is OS ? OPRATINGSYSTEMOPRATINGSYSTEM How do I use them? How do I manage them?

What is OS ? Interface between humans & computers Interface between software & hardware An OS is a software (a very complex one!) that makes the hardware usable by humans/software Hardware provides “raw computing power” OS makes the computing power conveniently available to users, by managing the hardware carefully to achieve good performance OS is a “Manager” of resources!

History of Computers Before the 1500s, in Europe, calculations were made with an abacus ◦ Invented around 500BC, available in many cultures (China, Mesopotamia, Japan, Greece, Rome, etc.) In 1642, Blaise Pascal (French mathematician, physicist, philosopher) invented a mechanical calculator called the Pascaline None of these machines had memory, and they required human intervention at each step

In 1822 Charles Babbage (English mathematician, philosopher), sometimes called the “father of computing” built the Difference Engine Machine designed to automate the computation (tabulation) of polynomial functions (which are known to be good approximations of many useful functions) ◦ Based on the “method of finite difference” ◦ Implements some storage In 1833 Babbage designed the Analytical Engine, but he died before he could build it ◦ It was built after his death, powered by steam

Generation of Computers First Generation ( ) Second Generation( ) Third Generation( ) Fourth Generation( ) Fifth Generation(1990 till date)

First Generation Second Generation Third Generation Fourth Generation Technology Vacuum TubesTransistors Integrated Circuits( multiple transistors) Microchips ( Billions of transistors) SizeFilled whole buildings Filled half a room Smaller Tiny-Palm Pilots is as powerful as old building sized computer

Generation 1 : ENIAC The ENIAC (Electronic Numerical Integrator and Computer) was unveiled in 1946: the first all-electronic, general-purpose digital computer

Generation 2 : IBM7094

Generation 3 : Integrated Circuits

Generation 4 : VLSI Generation 4 : VLSI Improvements to IC technology made it possible to integrate more and more transistors in a single chip ◦ SSI (Small Scale Integration): ◦ MSI (Medium Scale Integration): ,000 ◦ LSI (Large Scale Integration): 1, ,000 ◦ VLSI (Very Large Scale Integration): >10,000 Microprocessors

Generation 5? The term “Generation 5” is used sometimes to refer to all more or less “sci fi” future developments Voice recognition Artificial intelligence Quantum computing Bio computing Nano technology Learning Natural languages

LECTURE 3 LECTURE 3 UNIT 1

LECTURE 3 : CHAPTER I TOPICS Different types of operating systems Batch Operating System Multi programmed Multitasking

Early Batch System bring cards to 1401 read cards to tape put tape on 7094 which does computing put tape on 1401 which prints output

Batch Operating System In Batch processing same type of jobs batch (BATCH- a set of jobs with similar needs) together and execute at a time. The OS was simple, its major task was to transfer control from one job to the next. The job was submitted to the computer operator in form of punch cards. At some later time the output appeared. The OS was always resident in memory. (Ref. Fig. next slide) Common Input devices were card readers and tape drives.

Common output devices were line printers, tape drives, and card punches. Users did not interact directly with the computer systems, but he prepared a job (comprising of the program, the data, & some control information). OS User Program Area

Multi programmed System Multiprogramming is a technique to execute number of programs simultaneously by a single processor. In Multiprogramming, number of processes reside in main memory at a time. The OS picks and begins to executes one of the jobs in the main memory. If any I/O wait happened in a process, then CPU switches from that job to another job. Hence CPU in not idle at any time.

OS Job 1 Job 2 Job 3 Job 4 Job 5 Figure dipicts the layout of multiprogramming system. The main memory consists of 5 jobs at a time, the CPU executes one by one. Advantages: Efficient memory utilization Throughput increases CPU is never idle, so performance increases.

Multitasking/Time Sharing System Time sharing, or multitasking, is a logical extension of multiprogramming. Multiple jobs are executed by switching the CPU between them. In this, the CPU time is shared by different processes, so it is called as “Time sharing Systems”. Time slice is defined by the OS, for sharing CPU time between processes. Examples: Multics, Unix, etc.,

LECTURE 4 LECTURE 4 UNIT 1

LECTURE 4 : CHAPTER I TOPICS Different types of operating systems Multiprocessor System Distributed System Cluster Systems Real Time Systems

Multiprocessor System Multiprocessor systems with more than one CPU in close communication. Tightly coupled system – processors share memory and a clock; communication usually takes place through the shared memory. Advantages of Multiprocessor system: ◦ Increased throughput ◦ Economical ◦ Increased reliability  graceful degradation  fail-soft systems

Symmetric multiprocessing (SMP) ◦ Each processor runs an identical copy of the operating system. ◦ Many processes can run at once without performance deterioration. ◦ Most modern operating systems support SMP Asymmetric multiprocessing ◦ Each processor is assigned a specific task; master processor schedules and allocates work to slave processors. ◦ More common in extremely large systems

Symmetric Multiprocessing Architecture

Distributed System Distributed System Distribute the computation among several physical processors. Loosely coupled system – each processor has its own local memory; processors communicate with one another through various communications lines, such as high-speed buses or telephone lines. Advantages of distributed systems. ◦ Resources Sharing ◦ Computation speed up – load sharing ◦ Reliability ◦ Communications

Cluster Systems Like multiprocessor systems, but multiple systems working together ◦ Usually sharing storage via a storage-area network (SAN) ◦ Provides a high-availability service which survives failures  Asymmetric clustering has one machine in hot-standby mode  Symmetric clustering has multiple nodes running applications, monitoring each other

Cluster Systems Cluster Systems

Real Time Systems Real Time Systems A system is said to be Real Time if it is required to complete it’s work & deliver it’s services on time. Example – Flight Control System ◦ All tasks in that system must execute on time. Non Example – PC system

Hard and Soft Real time system Hard Real Time System ◦ Failure to meet deadlines is fatal ◦ Example : Flight Control System Soft Real Time System ◦ Late completion of jobs is undesirable but not fatal. ◦ System performance degrades as more & more jobs miss deadlines ◦ Example : Live video streaming, Online Databases

MSBTE Asked Questions 1. What is operating system? Explain the generations of computer system. Sum-2011 (4M) 2. Explain in detail various generations of operating system. Sum-2012 (8M), Win-2010(4M), Win-2014(4M) 3. Define operating system. State different types of operating system. Win-2009 (4M), Sum- 2010(4M) 4. List any four functions of operating system. Sum- 2010(4M), Sum-2014(4M), Win-2014(4M) 5. Differentiate between multiprogramming and multitasking. Sum-2009(4M), Sum-2010(4M), Win-2012(4M). 6. Describe real time system. State any two examples of its applications. Sum-2009(4M), Win-2009(4M), Win- 2010(4M), Sum-20013(4M), Win-2013(4M), Sum- 2014(4M), Win-2014(4M) 7. Explain Batch processing operating system. Sum-2009(4M), Sum-2013(4M), Win-2014(2M)

8. Explain Multiprocessor system concept. Win-2009(4M), Sum- 2011(4M), Sum-2014(4M), Win-2014(2M) 9. Explain Distributed system in detail. Sum-2010(4M), Sum- 2011(4M), Sum-2012(4M) 10. Describe Multiprogramming and Multitasking. WIn-2010(4M), Sum-2014(4M) 11. Describe time sharing system along with example. Win- 2010(4M), Win-2013(4M) 12. Differentiate between time sharing system and real time system. Sum-2011(4M) 13. What is Multitasking operating system? State advantages of multitasking operating system. Win-2011(4M), Win-2013(4M) 14. What is meant by Clustered system? Sum-2012(4M). 15. List any four system components and explain any two. Win- 2013(4M)