Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of...
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Transcript of Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of...
![Page 1: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/1.jpg)
Fall 2000 M.B. Ibáñez
Lecture 01Introduction
What is an Operating System?
The Evolution of Operating Systems
Course Outline
![Page 2: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/2.jpg)
Fall 2000 M.B. Ibáñez
What is an Operating System?
• A program that acts as an intermediary between a user of a computer and the computer hardware.
• Operating system goals:– Execute user programs – Make solving user problems easier– Allocate resources in a efficient and fair way
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Fall 2000 M.B. Ibáñez
Abstract View of System Components
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Hardware
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lots of different components,with different speds,different protocols for communication
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user 1 user 2 user n
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They want low cost and efficient services
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compiler text editor database system
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They want to have an easy life (don’t have to worry about speeds,use of file instead of blocks, large memory, etc)
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Operating System
![Page 4: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/4.jpg)
Fall 2000 M.B. Ibáñez
Services given by an Operating System
• Efficient program execution– Keeping all the devices busy– Good throughput for the user
• Access to I/O devices
• Controlled access to system and files
• Error detection and response
• Accounting
![Page 5: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/5.jpg)
Fall 2000 M.B. Ibáñez
Evolution of Operating SystemsSerial Processing
• From the late 1940s to the mid-1950s• There was no Operating System
– These machines were run from a console, consisting of display lights, toggle switches, some form of input device, and a printer
• Job scheduling– A user used a sign-up sheet to reserve machine time.
• How to run a job?– Load the compiler and source program into memory– Save the object program– Loading and linking together the object program and common functions
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Fall 2000 M.B. Ibáñez
Evolution of Operating SystemsSimple Batch Systems
• Mid-1950s
• The users did not interact directly with the computer system. The operator would sort programs into batches with similar requirements.
• The user prepared a job. A Monitor executed the job.$JOB
$FTN
<FORTRAN instructions>
$LOAD
$RUN
<data>
$END
![Page 7: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/7.jpg)
Fall 2000 M.B. Ibáñez
Memory Layout For a Resident Monitor
Boundary
InterruptProcessing
DeviceDrivers
JobSequencing
Control LanguageInterpreter
UserProgram
Area
Monitor
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From Operating Systems.Internals and Design Principles.W. Stalling. Prentice Hall
![Page 8: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/8.jpg)
Fall 2000 M.B. Ibáñez
There are some hardware features desirable
• Memory protection the user program should not alter the monitor’s
area
• Timer to prevent a single job from monopolizing the
system
• Privileged instructions I/O instructions by example
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Fall 2000 M.B. Ibáñez
Multiprogrammed Batch Systems
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time
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A
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A
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A
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B
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time
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A
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![Page 10: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/10.jpg)
Fall 2000 M.B. Ibáñez
Effects of Multiprogramming
Uniprogramming Multiprogramming
Processor use 17% 33%
Memory use 30% 67%
Disk use 33% 67%
Printer use 33% 67%
Elapsed time 30 min. 15 min.
Throughput rate 6 jobs/hr 12 jobs/hr
Mean response time 18 min. 10 min.
a
From Operating Systems.Internals and Design Principles.W. Stalling. Prentice Hall
![Page 11: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/11.jpg)
Fall 2000 M.B. Ibáñez
Time-sharing systems
• 1960s, they become common early 1970s
• Multiprogramming allows the processor to handle multiple batch jobs at a time
– Main objective: Maximize processor use
• Multiprogramming can be used to handle multiple interactive jobs: time -sharing
– Main objective: Minimize response time
• Processor time is shared among multiple users
• Multiple users simultaneously access the system through terminals
![Page 12: Fall 2000M.B. Ibáñez Lecture 01 Introduction What is an Operating System? The Evolution of Operating Systems Course Outline.](https://reader035.fdocuments.in/reader035/viewer/2022062718/56649e895503460f94b8e697/html5/thumbnails/12.jpg)
Fall 2000 M.B. Ibáñez
Primitive Time-sharing Operating System
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Monitorjob 1free
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Monitorfreejob 2
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Monitorfreejob2job3
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Monitorfreejob1job3
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Fall 2000 M.B. Ibáñez
New problems for the Operating Systems
• Multiple jobs are in memory– They must be protected from interfering with each other
• Multiple interactive users– The file system must be protected so that only authorized
users have access to a particular file
• The contention for resources, such as printers and mass storage devices, must be handled
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Fall 2000 M.B. Ibáñez
Characteristics of Modern Operating Systems.What forces a change?
Developments in hardware
• Multiprocessor machines
• Greatly increased machine speed
• High-speed network attachments
• Increasing size and variety of memory storage services
New applications
• Multimedia applications
• Internet and Web access
• client/server computing
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Fall 2000 M.B. Ibáñez
Characteristics of Modern Operating Systems Microkernel architecture
• A microkerner architecture assigns only a few essential functions to the kernel, such as– Address spaces
– Interprocess communication
– Basic scheduling
• The microkernel approach simplifies implementation, provides flexibility, and is well suited to a distributed environment
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Fall 2000 M.B. Ibáñez
Characteristics of Modern Operating SystemsMultithreading
• Multithreading– technique in which a process, executing an application,
is divided into threads that can run simultaneously
• Thread– dispatchable unit of work
– executes sequentially and is interruptable
• Process – collection of one or more threads
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Fall 2000 M.B. Ibáñez
Characteristics of Modern Operating Systems Symmetric multiprocessing (SMP)
• Systems with multiple multiprocessors– there are multiple processors
– these processors share same main memory and I/O facilities
– All processors can perform the same functions
• Advantages over uniprocessor architectures– Performance
– Availability
– Incremental growth
– Scaling
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Fall 2000 M.B. Ibáñez
Characteristics of Modern Operating Systems Distributed operating systems
• provides the illusion of a single main memory
• used for distributed file system
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Fall 2000 M.B. Ibáñez
Outline of the Course
• Processes
• Memory
• I/O devices
• File systems
• Protection and security