The document discusses operating systems, including their functions, goals, historical development, and types used in different computers. It provides an overview of how operating systems act as an interface between the user and computer hardware, manage resources and allow for easier programming. Key points include that operating systems evolved from batch processing to support timesharing, personal computing and distributed systems. The types of operating systems depend on factors like response time and how data is input, with examples being batch, interactive, real-time, hybrid and embedded systems.

1. OPERATING SYSTEM
Genesis,
Development &
Functions

2. OPERATING SYSTEM
 Program that acts as an intermediary/interface between a user of a computer and
the computer hardware
 It provides a user-friendly environment in which a user may easily develop and
execute programs
 Otherwise, hardware knowledge would be mandatory for computer programming.

3. OPERATING SYSTEM
Operating system goals:
 Execute programs and solve user problems
easily
 Make the computer system convenient to
use
manner
Manage all hardware and software
 Controls every file, device, section of main
memory and nanosecond of processing time
 Controls who can use the system

4. • When you turn on the computer, the CPU automatically begins executing instructions
stored in ROM.
• The operating system (OS) loads from the disk into part of the system’s memory.
• OS loads the application program into memory and remains in memory, So that, it can
provide services to the application program—display on-screen menus, communicate
OPERATING SYSTEM

5. WHAT DOES AN OPERATING
SYSTEM DO?
Every computer depends on an operating system to:
 Keep hardware running efficiently
 Maintains file system
 Support multitasking
 Manage virtual memory
Operating system runs continuously when computer is on….

6. FUNCTIONS OF AN OPERATING
SYSTEM
Includes five essential subsystem managers
 Memory Manager
 Processor Manager
 Device Manager
 File Manager
 Network Manager

7. MAIN MEMORY MANAGEMENT
In charge of main memory
 Random Access Memory (RAM)
Responsibilities include:
 Preserving space in main memory occupied by
operating system
 Checking validity and legality of memory space
request
 Setting up memory tracking table
 Tracks usage of memory by sections
 Needed in multiuser environment
 De-allocating memory to reclaim it

8. PROCESSOR MANAGEMENT
In charge of allocating (CPU)
Tracks process status
 An instance of program execution
Two levels of responsibility:
 Handle jobs as they enter the system
 Handled by Job Scheduler
 Manage each process within those jobs
 Handled by Process Scheduler

9. DEVICE MANAGEMENT
In charge of monitoring all resources
 Devices, channels, and control units
Responsibilities include:
 Choosing most efficient resource allocation
method
 Printers, ports, disk drives, etc.
 Based on scheduling policy
 Allocating the device
 Starting device operation
 Deallocating the device

10. FILE MANAGEMENT
In charge of tracking every file in the system
 Data files, program files, compilers, application
programs
Responsibilities include:
 Enforcing user/program resource access
restrictions
 Uses predetermined access policies
 Controlling user/program modification
restrictions
 Read-only, read-write, create, delete
 Allocating resource
 Opening the file
 De-allocating file (by closing it)

11. NETWORK MANAGER
 In all modern operating systems
 Assumes responsibility for networking tasks
 Convenient way for users to share resources
 Retains user access control
Resources include:
 Hardware (CPUs, memory areas, printers, tape
drives, modems, and disk drives)
 Software (compilers, application programs, and
data files)

12. FUNCTIONS OF AN OPERATING
SYSTEM
Each manager:
 Works closely with other managers
 Performs a unique role
Manager task
 Monitor its resources continuously
 Enforce policies determining:
 Who gets what, when, and how much
 Allocate the resource (when
appropriate)
 De-allocate the resource (when
appropriate)

13. HISTORICAL DEVELOPMENT OF AN
OPERATING SYSTEM

14. HISTORICAL DEVELOPMENT OF OS
Upto year 1955
 Computers based on vacuum tube
technology
 No standard operating system software
 Poor machine utilization
From 1956- 1963
 I/O device speed gradually became faster
 Records blocked before retrieval or storage
 Access methods developed
 Buffer between I/O and CPU introduced & Reduced speed
discrepancy

15. HISTORICAL DEVELOPMENT OF OS
TILL 1970
 Faster CPUs Speed caused problems with slower I/O devices
 Multiprogramming schemes used to reduce speed discrepancy with CPU
 Main memory physical capacity limitations
 Virtual memory developed to solve physical limitation
 Database management software was developed
 A number of query systems introduced
 Programs started using English-like words, modular structures, and standard

16. HISTORICAL DEVELOPMENT OF OS
From 1971 to 1980
 Cost/performance ratio of computer
components
 More flexible hardware (firmware)
 Multiprocessing
 Allowed parallel program execution
 Evolution of personal computers
Upto 1990
 Demand for Internet capability
 Sparked production of networking capability
 Increased networking
 Tighter security demands to protect hardware and
software
 Multimedia applications
 Demanding additional power, flexibility, and device
compatibility for most operating systems

17. FROM 1990 TILL PRESENT
 Primary design features support:
 Multimedia applications
 Internet and Web access
 Client/server computing
 Evolution of high-speed communications
 Distributed processing and networked systems introduced
 Computer systems requirements
 Increased CPU speed
 High-speed network attachments
 Increased number and variety of storage devices
 Virtualization

18. EVOLUTION OF COMPUTER OPERATING
SYSTEM

19. EVOLUTION OF OPERATING SYSTEM
 The evolution of operating systems went through seven major phases.
 Each of them significantly changed the ways in which users accessed computers
through the open shop, batch processing, multiprogramming, timesharing,
concurrent programming, personal computing, and distributed systems.

20. EVOLUTION OF OPERATING SYSTEM
Major Phases Technical Innovations
Open Shop The idea of OS
Batch Processing Tape batching,
First-in, first-out scheduling.
Multi-programming Processor multiplexing, Indivisible operations, Demand paging, Input/output spooling, Priority scheduling,
Remote job entry
Timesharing Simultaneous user interaction,
On-line file systems
Concurrent Programming Hierarchical systems, Extensible kernels, Parallel programming concepts, Secure parallel languages
Personal Computing Graphic user interfaces
Distributed Systems Remote servers

21. OPERATING SYSTEMS IN DIFFERENT TYPES
OF COMPUTERS

22. OPERATING SYSTEM TYPES
Five categories
 Batch
 Interactive
 Real-time
 Hybrid
 Embedded
Two distinguishing features
 Response time
 How data enters into the system

23. BATCH SYSTEMS & INTERACTIVE
SYSTEMS
Batch Systems
 Input relied on punched cards or tape
 Efficiency measured in throughput
 Faster turnaround than batch systems
 Slower than real-time systems
 Introduced to provide fast turnaround when
debugging programs
 Time-sharing software developed for operating
system

24. REAL-TIME SYSTEMS
 Reliability is key
 Fast and time limit sensitive
 Used in time-critical environments
 Space flights, airport traffic control, high-speed aircraft
 Industrial processes
 Distribution of electricity
 Telephone switching
 Must be 100% responsive, 100% of the time

25. HYBRID & EMBEDDED SYSTEMS
Hybrid systems
 Combination of batch and interactive
 Accept and run batch programs in the
background
 Interactive load is light
Embedded systems
 Computers placed inside other products
 Adds features and capabilities
 Operating system requirements
 Perform specific set of programs
 Not interchangeable among systems