SlideShare a Scribd company logo
1 of 39
Operating Systems:
 Internals and Design Principles, 6/E
           William Stallings


        Chapter 2
Operating System Overview




                     Patricia Roy
           Manatee Community College, Venice,
                          FL
                  ©2008, Prentice Hall
Operating System
• A program that controls the execution of
  application programs
• An interface between applications and
  hardware
Operating System Objectives
• Convenience: make the computer more
  convenient to use
• Efficiency: in using the system resources
• Ability to evolve: to permit the effective
  development, testing, and introduction of
  new system functions.
Layers and Views
Services Provided by the OS
• Program development
    – Editors and debuggers
•   Program execution
•   Access I/O devices
•   Controlled access to files
•   System access
Services Provided by the OS
• Error detection and response
  – Internal and external hardware errors
  – Software errors
  – OS provide a response that clears the error
    (ending the program that cause error, retry the
    operation, or simply reporting the error to the
    application).
Services Provided by the OS
• Accounting
  – Collect usage statistics
  – Monitor performance
  – Used to anticipate future enhancements
  – Used for billing purposes
Operating System
• Responsible for managing resources
• Functions same way as ordinary computer
  software
  – It is a program that is executed
• Operating system relinquishes control of
  the processor
OS as Resource Manager
Kernel
• Portion of operating system that is in main
  memory
• Contains most frequently used functions
• Also called the nucleus
Evolution of Operating
                Systems
• Serial processing
  – No operating system
  – Programs in machine code loaded from input
    device
  – If an error halted the program, the error
    condition was indicated by lights.
  – The output appears on the printer
Evolution of Operating
                Systems
• Serial processing, two main problems:
  – Schedule time: waste of time for short
    programs. Problem if not finish in the
    allocated time
  – Setup time: included loading the compiler,
    source program, saving compiled program,
    and loading and linking
Evolution of Operating
                Systems
• Simple batch system: the first OS (batch
  OS) on IBM 701 by general Motors
  – Monitor
    • Software that controls the sequence of events
    • Batch jobs together
    • Program returns control to monitor when finished,
      then the monitor automatically begin loading the
      next program.
Desirable Hardware Features
• Memory protection
  – Does not allow the memory area containing
    the monitor to be altered
• Timer
  – Prevents a job from monopolizing the system
  – If the timer expires the user program stopped.
Desirable Hardware Features
• Privileged instructions
  – Certain machine level instructions can only be
    executed by the monitor such as I/O instr.
• Interrupts
  – Early computer models did not have this
    capability. This feature gives the OS the
    flexibility in relinquishing control and regaining
    control to and regaining control from user
    programs.
Memory Protection
• User program executes in user mode
  – Certain instructions may not be executed
  – Certain area’s of memory are protected from
    user’s use.
Memory Protection
• Monitor executes in system mode(Kernel
  mode)
  – Privileged instructions are executed
  – Protected areas of memory may be accessed
System Utilization Example
Uniprogramming
• Processor must wait for I/O instruction to
  complete before proceeding
Multiprogramming
• When one job needs to wait for I/O, the
  processor can switch to the other job
Multiprogramming
Utilization Histograms
Example
Time Sharing Systems
• Using multiprogramming to handle multiple
  interactive jobs
• Processor’s time is shared among multiple
  users
• Multiple users simultaneously access the
  system through terminals, with the OS
  interleaving the execution of each user
  program in a short burst or quantum of
  computation.
Major Achievements
There have been five major theoretical advances
in the development of operating systems:
•   Processes
•   Memory management
•   Information protection and security
•   Scheduling and resource management
•   System structure
Process
• A program in execution
• An instance of a program running on a
  computer
• The entity that can be assigned to and
  executed on a processor
Process
• Consists of three components
  – An executable program
  – Associated data needed by the program
  – Execution context of the program
    • All information the operating system needs to
      manage the process
Process
Memory Management
The os has five principle storage management
responsibilities:
•   Process isolation
•   Automatic allocation and management
•   Support of modular programming
•   Protection and access control
•   Long-term storage
Information Protection and
             Security
Work in security and protection can be
  grouped into four categories:
• Availability
  – Concerned with protecting the system against
    interruption
• Confidentiality
  – Assuring that users cannot read data for
    which access is unauthorized
Information Protection and
             Security
• Data integrity
  – Protection of data from unauthorized
    modification
• Authenticity
  – Concerned with the proper verification of the
    identity of users and the validity of messages
    or data
Scheduling and Resource
          Management
Any resource allocation and scheduling policy must
  consider three factors:
• Fairness
  – Give equal and fair access to resources
• Differential responsiveness
  – Discriminate among different classes of jobs
• Efficiency
  – Maximize throughput, minimize response time,
    and accommodate as many uses as possible
System Structure
• View the system as a series of levels
• Each level performs a related subset of
  functions
• Each level relies on the next lower level to
  perform more primitive functions
• This decomposes a problem into a number
  of more manageable subproblems
Levels
• Level 1
  – Electronic circuits
  – Objects are registers, memory cells, and logic
    gates
  – Operations are clearing a register or reading a
    memory location
• Level 2
  – Processor’s instruction set
  – Operations such as add, subtract, load, and
    store
Levels
• Level 3
  – Adds the concept of a procedure or
    subroutine, plus call/return operations
• Level 4
  – Interrupts
Concepts Related to
         Multiprogramming
• Level 5
  – Process as a program in execution
  – Suspend and resume processes
• Level 6
  – Secondary storage devices
  – Transfer of blocks of data
ConceptsRelated to
         Multiprogramming
• Level 7
  – Creates logical address space for processes
  – Organizes virtual address space into blocks
Deal with External Objects
• Level 8
  – Communication of information and messages
    between processes
• Level 9
  – Supports long-term storage of named files
• Level 10
  – Provides access to external devices using
    standardized interfaces
Deal with External Objects
• Level 11
  – Responsible for maintaining the association
    between the external and internal identifiers
• Level 12
  – Provides full-featured facility for the support of
    processes
• Level 13
  – Provides an interface to the OS for the user

More Related Content

What's hot (20)

7 Deadlocks
7 Deadlocks7 Deadlocks
7 Deadlocks
 
The ps Command
The ps CommandThe ps Command
The ps Command
 
File system hiearchy
File system hiearchyFile system hiearchy
File system hiearchy
 
Pipelining
PipeliningPipelining
Pipelining
 
Complete Operating System notes
Complete Operating System notesComplete Operating System notes
Complete Operating System notes
 
Os unit 3 , process management
Os unit 3 , process managementOs unit 3 , process management
Os unit 3 , process management
 
17 cpu scheduling and scheduling criteria
17 cpu scheduling and scheduling criteria 17 cpu scheduling and scheduling criteria
17 cpu scheduling and scheduling criteria
 
Lecture 1 introduction to parallel and distributed computing
Lecture 1   introduction to parallel and distributed computingLecture 1   introduction to parallel and distributed computing
Lecture 1 introduction to parallel and distributed computing
 
Process management in os
Process management in osProcess management in os
Process management in os
 
Memory Management
Memory ManagementMemory Management
Memory Management
 
Process threads operating system.
Process threads operating system.Process threads operating system.
Process threads operating system.
 
Storage management
Storage managementStorage management
Storage management
 
Introduction to System Calls
Introduction to System CallsIntroduction to System Calls
Introduction to System Calls
 
Mainframe systems
Mainframe systemsMainframe systems
Mainframe systems
 
Linux Memory Management
Linux Memory ManagementLinux Memory Management
Linux Memory Management
 
Distributed Operating System_1
Distributed Operating System_1Distributed Operating System_1
Distributed Operating System_1
 
40 demand paging
40 demand paging40 demand paging
40 demand paging
 
Processes and threads
Processes and threadsProcesses and threads
Processes and threads
 
Cs8493 unit 4
Cs8493 unit 4Cs8493 unit 4
Cs8493 unit 4
 
Cache memory
Cache memoryCache memory
Cache memory
 

Similar to Lec # 1 chapter 2

cs-intro-os.ppt
cs-intro-os.pptcs-intro-os.ppt
cs-intro-os.pptinfomerlin
 
operating-system-03092013175227-operating-system.ppt
operating-system-03092013175227-operating-system.pptoperating-system-03092013175227-operating-system.ppt
operating-system-03092013175227-operating-system.pptTiktokIndia2
 
Operating systems introduction
Operating systems   introductionOperating systems   introduction
Operating systems introductionveeravanithaD
 
SISTEMAS OPERATIVOS.pptx
SISTEMAS OPERATIVOS.pptxSISTEMAS OPERATIVOS.pptx
SISTEMAS OPERATIVOS.pptxAnalistaSoporte
 
4 Module - Operating Systems Configuration and Use by Mark John Lado
4 Module - Operating Systems Configuration and Use by Mark John Lado4 Module - Operating Systems Configuration and Use by Mark John Lado
4 Module - Operating Systems Configuration and Use by Mark John LadoMark John Lado, MIT
 
list of all Functions of operating system.pptx
list of all Functions of operating system.pptxlist of all Functions of operating system.pptx
list of all Functions of operating system.pptxErAnjuBala
 
Kernel security Concepts
Kernel security ConceptsKernel security Concepts
Kernel security ConceptsMohit Saxena
 
Engg-0505-IT-Operating-Systems-2nd-year.pdf
Engg-0505-IT-Operating-Systems-2nd-year.pdfEngg-0505-IT-Operating-Systems-2nd-year.pdf
Engg-0505-IT-Operating-Systems-2nd-year.pdfnikhil287188
 

Similar to Lec # 1 chapter 2 (20)

Chapter02-rev.pptx
Chapter02-rev.pptxChapter02-rev.pptx
Chapter02-rev.pptx
 
cs-intro-os.ppt
cs-intro-os.pptcs-intro-os.ppt
cs-intro-os.ppt
 
Chapter02
Chapter02Chapter02
Chapter02
 
Chapter02
Chapter02Chapter02
Chapter02
 
operating-system-03092013175227-operating-system.ppt
operating-system-03092013175227-operating-system.pptoperating-system-03092013175227-operating-system.ppt
operating-system-03092013175227-operating-system.ppt
 
Operating systems introduction
Operating systems   introductionOperating systems   introduction
Operating systems introduction
 
SISTEMAS OPERATIVOS.pptx
SISTEMAS OPERATIVOS.pptxSISTEMAS OPERATIVOS.pptx
SISTEMAS OPERATIVOS.pptx
 
4 Module - Operating Systems Configuration and Use by Mark John Lado
4 Module - Operating Systems Configuration and Use by Mark John Lado4 Module - Operating Systems Configuration and Use by Mark John Lado
4 Module - Operating Systems Configuration and Use by Mark John Lado
 
list of all Functions of operating system.pptx
list of all Functions of operating system.pptxlist of all Functions of operating system.pptx
list of all Functions of operating system.pptx
 
Kernel security Concepts
Kernel security ConceptsKernel security Concepts
Kernel security Concepts
 
Os1
Os1Os1
Os1
 
Unit 2.pptx
Unit 2.pptxUnit 2.pptx
Unit 2.pptx
 
Unit 2.pptx
Unit 2.pptxUnit 2.pptx
Unit 2.pptx
 
Operating system Chapter One
Operating system Chapter OneOperating system Chapter One
Operating system Chapter One
 
Os unit i
Os unit iOs unit i
Os unit i
 
Operating System-adi.pdf
Operating System-adi.pdfOperating System-adi.pdf
Operating System-adi.pdf
 
Os concepts
Os conceptsOs concepts
Os concepts
 
Engg-0505-IT-Operating-Systems-2nd-year.pdf
Engg-0505-IT-Operating-Systems-2nd-year.pdfEngg-0505-IT-Operating-Systems-2nd-year.pdf
Engg-0505-IT-Operating-Systems-2nd-year.pdf
 
OS chapter 1.pptx
OS chapter 1.pptxOS chapter 1.pptx
OS chapter 1.pptx
 
OS chapter 1.pptx
OS chapter 1.pptxOS chapter 1.pptx
OS chapter 1.pptx
 

Recently uploaded

Infrared simulation and processing on Nvidia platforms
Infrared simulation and processing on Nvidia platformsInfrared simulation and processing on Nvidia platforms
Infrared simulation and processing on Nvidia platformsYoss Cohen
 
So einfach geht modernes Roaming fuer Notes und Nomad.pdf
So einfach geht modernes Roaming fuer Notes und Nomad.pdfSo einfach geht modernes Roaming fuer Notes und Nomad.pdf
So einfach geht modernes Roaming fuer Notes und Nomad.pdfpanagenda
 
QMMS Lesson 2 - Using MS Excel Formula.pdf
QMMS Lesson 2 - Using MS Excel Formula.pdfQMMS Lesson 2 - Using MS Excel Formula.pdf
QMMS Lesson 2 - Using MS Excel Formula.pdfROWELL MARQUINA
 
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesHow to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesThousandEyes
 
All These Sophisticated Attacks, Can We Really Detect Them - PDF
All These Sophisticated Attacks, Can We Really Detect Them - PDFAll These Sophisticated Attacks, Can We Really Detect Them - PDF
All These Sophisticated Attacks, Can We Really Detect Them - PDFMichael Gough
 
Design pattern talk by Kaya Weers - 2024 (v2)
Design pattern talk by Kaya Weers - 2024 (v2)Design pattern talk by Kaya Weers - 2024 (v2)
Design pattern talk by Kaya Weers - 2024 (v2)Kaya Weers
 
Glenn Lazarus- Why Your Observability Strategy Needs Security Observability
Glenn Lazarus- Why Your Observability Strategy Needs Security ObservabilityGlenn Lazarus- Why Your Observability Strategy Needs Security Observability
Glenn Lazarus- Why Your Observability Strategy Needs Security Observabilityitnewsafrica
 
Long journey of Ruby standard library at RubyConf AU 2024
Long journey of Ruby standard library at RubyConf AU 2024Long journey of Ruby standard library at RubyConf AU 2024
Long journey of Ruby standard library at RubyConf AU 2024Hiroshi SHIBATA
 
A Glance At The Java Performance Toolbox
A Glance At The Java Performance ToolboxA Glance At The Java Performance Toolbox
A Glance At The Java Performance ToolboxAna-Maria Mihalceanu
 
React JS; all concepts. Contains React Features, JSX, functional & Class comp...
React JS; all concepts. Contains React Features, JSX, functional & Class comp...React JS; all concepts. Contains React Features, JSX, functional & Class comp...
React JS; all concepts. Contains React Features, JSX, functional & Class comp...Karmanjay Verma
 
Bridging Between CAD & GIS: 6 Ways to Automate Your Data Integration
Bridging Between CAD & GIS:  6 Ways to Automate Your Data IntegrationBridging Between CAD & GIS:  6 Ways to Automate Your Data Integration
Bridging Between CAD & GIS: 6 Ways to Automate Your Data Integrationmarketing932765
 
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...Jeffrey Haguewood
 
Genislab builds better products and faster go-to-market with Lean project man...
Genislab builds better products and faster go-to-market with Lean project man...Genislab builds better products and faster go-to-market with Lean project man...
Genislab builds better products and faster go-to-market with Lean project man...Farhan Tariq
 
A Framework for Development in the AI Age
A Framework for Development in the AI AgeA Framework for Development in the AI Age
A Framework for Development in the AI AgeCprime
 
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotes
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotesMuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotes
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotesManik S Magar
 
Potential of AI (Generative AI) in Business: Learnings and Insights
Potential of AI (Generative AI) in Business: Learnings and InsightsPotential of AI (Generative AI) in Business: Learnings and Insights
Potential of AI (Generative AI) in Business: Learnings and InsightsRavi Sanghani
 
Generative AI - Gitex v1Generative AI - Gitex v1.pptx
Generative AI - Gitex v1Generative AI - Gitex v1.pptxGenerative AI - Gitex v1Generative AI - Gitex v1.pptx
Generative AI - Gitex v1Generative AI - Gitex v1.pptxfnnc6jmgwh
 
Connecting the Dots for Information Discovery.pdf
Connecting the Dots for Information Discovery.pdfConnecting the Dots for Information Discovery.pdf
Connecting the Dots for Information Discovery.pdfNeo4j
 
WomenInAutomation2024: AI and Automation for eveyone
WomenInAutomation2024: AI and Automation for eveyoneWomenInAutomation2024: AI and Automation for eveyone
WomenInAutomation2024: AI and Automation for eveyoneUiPathCommunity
 

Recently uploaded (20)

Infrared simulation and processing on Nvidia platforms
Infrared simulation and processing on Nvidia platformsInfrared simulation and processing on Nvidia platforms
Infrared simulation and processing on Nvidia platforms
 
So einfach geht modernes Roaming fuer Notes und Nomad.pdf
So einfach geht modernes Roaming fuer Notes und Nomad.pdfSo einfach geht modernes Roaming fuer Notes und Nomad.pdf
So einfach geht modernes Roaming fuer Notes und Nomad.pdf
 
QMMS Lesson 2 - Using MS Excel Formula.pdf
QMMS Lesson 2 - Using MS Excel Formula.pdfQMMS Lesson 2 - Using MS Excel Formula.pdf
QMMS Lesson 2 - Using MS Excel Formula.pdf
 
How Tech Giants Cut Corners to Harvest Data for A.I.
How Tech Giants Cut Corners to Harvest Data for A.I.How Tech Giants Cut Corners to Harvest Data for A.I.
How Tech Giants Cut Corners to Harvest Data for A.I.
 
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesHow to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
 
All These Sophisticated Attacks, Can We Really Detect Them - PDF
All These Sophisticated Attacks, Can We Really Detect Them - PDFAll These Sophisticated Attacks, Can We Really Detect Them - PDF
All These Sophisticated Attacks, Can We Really Detect Them - PDF
 
Design pattern talk by Kaya Weers - 2024 (v2)
Design pattern talk by Kaya Weers - 2024 (v2)Design pattern talk by Kaya Weers - 2024 (v2)
Design pattern talk by Kaya Weers - 2024 (v2)
 
Glenn Lazarus- Why Your Observability Strategy Needs Security Observability
Glenn Lazarus- Why Your Observability Strategy Needs Security ObservabilityGlenn Lazarus- Why Your Observability Strategy Needs Security Observability
Glenn Lazarus- Why Your Observability Strategy Needs Security Observability
 
Long journey of Ruby standard library at RubyConf AU 2024
Long journey of Ruby standard library at RubyConf AU 2024Long journey of Ruby standard library at RubyConf AU 2024
Long journey of Ruby standard library at RubyConf AU 2024
 
A Glance At The Java Performance Toolbox
A Glance At The Java Performance ToolboxA Glance At The Java Performance Toolbox
A Glance At The Java Performance Toolbox
 
React JS; all concepts. Contains React Features, JSX, functional & Class comp...
React JS; all concepts. Contains React Features, JSX, functional & Class comp...React JS; all concepts. Contains React Features, JSX, functional & Class comp...
React JS; all concepts. Contains React Features, JSX, functional & Class comp...
 
Bridging Between CAD & GIS: 6 Ways to Automate Your Data Integration
Bridging Between CAD & GIS:  6 Ways to Automate Your Data IntegrationBridging Between CAD & GIS:  6 Ways to Automate Your Data Integration
Bridging Between CAD & GIS: 6 Ways to Automate Your Data Integration
 
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...
Email Marketing Automation for Bonterra Impact Management (fka Social Solutio...
 
Genislab builds better products and faster go-to-market with Lean project man...
Genislab builds better products and faster go-to-market with Lean project man...Genislab builds better products and faster go-to-market with Lean project man...
Genislab builds better products and faster go-to-market with Lean project man...
 
A Framework for Development in the AI Age
A Framework for Development in the AI AgeA Framework for Development in the AI Age
A Framework for Development in the AI Age
 
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotes
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotesMuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotes
MuleSoft Online Meetup Group - B2B Crash Course: Release SparkNotes
 
Potential of AI (Generative AI) in Business: Learnings and Insights
Potential of AI (Generative AI) in Business: Learnings and InsightsPotential of AI (Generative AI) in Business: Learnings and Insights
Potential of AI (Generative AI) in Business: Learnings and Insights
 
Generative AI - Gitex v1Generative AI - Gitex v1.pptx
Generative AI - Gitex v1Generative AI - Gitex v1.pptxGenerative AI - Gitex v1Generative AI - Gitex v1.pptx
Generative AI - Gitex v1Generative AI - Gitex v1.pptx
 
Connecting the Dots for Information Discovery.pdf
Connecting the Dots for Information Discovery.pdfConnecting the Dots for Information Discovery.pdf
Connecting the Dots for Information Discovery.pdf
 
WomenInAutomation2024: AI and Automation for eveyone
WomenInAutomation2024: AI and Automation for eveyoneWomenInAutomation2024: AI and Automation for eveyone
WomenInAutomation2024: AI and Automation for eveyone
 

Lec # 1 chapter 2

  • 1. Operating Systems: Internals and Design Principles, 6/E William Stallings Chapter 2 Operating System Overview Patricia Roy Manatee Community College, Venice, FL ©2008, Prentice Hall
  • 2. Operating System • A program that controls the execution of application programs • An interface between applications and hardware
  • 3. Operating System Objectives • Convenience: make the computer more convenient to use • Efficiency: in using the system resources • Ability to evolve: to permit the effective development, testing, and introduction of new system functions.
  • 5. Services Provided by the OS • Program development – Editors and debuggers • Program execution • Access I/O devices • Controlled access to files • System access
  • 6. Services Provided by the OS • Error detection and response – Internal and external hardware errors – Software errors – OS provide a response that clears the error (ending the program that cause error, retry the operation, or simply reporting the error to the application).
  • 7. Services Provided by the OS • Accounting – Collect usage statistics – Monitor performance – Used to anticipate future enhancements – Used for billing purposes
  • 8. Operating System • Responsible for managing resources • Functions same way as ordinary computer software – It is a program that is executed • Operating system relinquishes control of the processor
  • 9. OS as Resource Manager
  • 10. Kernel • Portion of operating system that is in main memory • Contains most frequently used functions • Also called the nucleus
  • 11. Evolution of Operating Systems • Serial processing – No operating system – Programs in machine code loaded from input device – If an error halted the program, the error condition was indicated by lights. – The output appears on the printer
  • 12. Evolution of Operating Systems • Serial processing, two main problems: – Schedule time: waste of time for short programs. Problem if not finish in the allocated time – Setup time: included loading the compiler, source program, saving compiled program, and loading and linking
  • 13. Evolution of Operating Systems • Simple batch system: the first OS (batch OS) on IBM 701 by general Motors – Monitor • Software that controls the sequence of events • Batch jobs together • Program returns control to monitor when finished, then the monitor automatically begin loading the next program.
  • 14. Desirable Hardware Features • Memory protection – Does not allow the memory area containing the monitor to be altered • Timer – Prevents a job from monopolizing the system – If the timer expires the user program stopped.
  • 15. Desirable Hardware Features • Privileged instructions – Certain machine level instructions can only be executed by the monitor such as I/O instr. • Interrupts – Early computer models did not have this capability. This feature gives the OS the flexibility in relinquishing control and regaining control to and regaining control from user programs.
  • 16. Memory Protection • User program executes in user mode – Certain instructions may not be executed – Certain area’s of memory are protected from user’s use.
  • 17. Memory Protection • Monitor executes in system mode(Kernel mode) – Privileged instructions are executed – Protected areas of memory may be accessed
  • 19. Uniprogramming • Processor must wait for I/O instruction to complete before proceeding
  • 20. Multiprogramming • When one job needs to wait for I/O, the processor can switch to the other job
  • 24. Time Sharing Systems • Using multiprogramming to handle multiple interactive jobs • Processor’s time is shared among multiple users • Multiple users simultaneously access the system through terminals, with the OS interleaving the execution of each user program in a short burst or quantum of computation.
  • 25. Major Achievements There have been five major theoretical advances in the development of operating systems: • Processes • Memory management • Information protection and security • Scheduling and resource management • System structure
  • 26. Process • A program in execution • An instance of a program running on a computer • The entity that can be assigned to and executed on a processor
  • 27. Process • Consists of three components – An executable program – Associated data needed by the program – Execution context of the program • All information the operating system needs to manage the process
  • 29. Memory Management The os has five principle storage management responsibilities: • Process isolation • Automatic allocation and management • Support of modular programming • Protection and access control • Long-term storage
  • 30. Information Protection and Security Work in security and protection can be grouped into four categories: • Availability – Concerned with protecting the system against interruption • Confidentiality – Assuring that users cannot read data for which access is unauthorized
  • 31. Information Protection and Security • Data integrity – Protection of data from unauthorized modification • Authenticity – Concerned with the proper verification of the identity of users and the validity of messages or data
  • 32. Scheduling and Resource Management Any resource allocation and scheduling policy must consider three factors: • Fairness – Give equal and fair access to resources • Differential responsiveness – Discriminate among different classes of jobs • Efficiency – Maximize throughput, minimize response time, and accommodate as many uses as possible
  • 33. System Structure • View the system as a series of levels • Each level performs a related subset of functions • Each level relies on the next lower level to perform more primitive functions • This decomposes a problem into a number of more manageable subproblems
  • 34. Levels • Level 1 – Electronic circuits – Objects are registers, memory cells, and logic gates – Operations are clearing a register or reading a memory location • Level 2 – Processor’s instruction set – Operations such as add, subtract, load, and store
  • 35. Levels • Level 3 – Adds the concept of a procedure or subroutine, plus call/return operations • Level 4 – Interrupts
  • 36. Concepts Related to Multiprogramming • Level 5 – Process as a program in execution – Suspend and resume processes • Level 6 – Secondary storage devices – Transfer of blocks of data
  • 37. ConceptsRelated to Multiprogramming • Level 7 – Creates logical address space for processes – Organizes virtual address space into blocks
  • 38. Deal with External Objects • Level 8 – Communication of information and messages between processes • Level 9 – Supports long-term storage of named files • Level 10 – Provides access to external devices using standardized interfaces
  • 39. Deal with External Objects • Level 11 – Responsible for maintaining the association between the external and internal identifiers • Level 12 – Provides full-featured facility for the support of processes • Level 13 – Provides an interface to the OS for the user