Fundamental Concepts and History

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1 Fundamental Concepts and History Minsoo Ryu Real-Time Computing and Communications Lab. Hanyang University

2 Topics Covered I. Fundamental Concepts II. Evolution of OS 2

3 Key Concepts of OS 1. Abstraction 2. Protection 3. Illusion 4. Coordination and Optimization 3

4 Abstraction Pick out only key features to reduce complexity Provide a clean, uniform, and standard interface to users hiding hardware complexity e.g.) POSIX APIs (Application Programming Interfaces) Application S/W Application S/W Operating System S/W Hardware Without OS Hardware With OS 4

device drivers, scheduling, GUI POSIX Standard API

5 OS can be viewed as a Big Library An organized collection of reusable program code Bootstrapping, device drivers, scheduling, GUI POSIX Standard API implementations University Library POSIX Standard

6 Typical System Structure App Application 1 Application 2 Application N Library System Calls GUI Manager Process & Thread Memory Management Inter-process Management OS File System Sync Primitives CPU Scheduling Network Protocols Device Driver Device Driver Interrupt & Exception Handlers Device Driver Device Driver HW Processors, Memory, Storage, Network, Sensors, Actuators 6

7 System Calls vs. Library Calls System calls provide the interface between application SW and the operating system 7

8 Execution Flow App Application 1 Application 2 Application N printf( ) Library receive( ) write( ) System Calls read( ) GUI Manager ( ) Scheduler IPC OS File System ( ) Memory Manager proc_protocol( ) Device Driver write( ) interrupt( ) Device Driver Device Driver HW Processors, Memory, Display, Network, Sensors, Actuators 8

9 Execution Flow without OS Event Handler Structure ISR_#1( ) helper_#1( ) ISR_#2( ) SW wait( ) bootstrap( ) interrupt( ) ISR_#3( ) ISR_#n( ) helper_#2( ) helper_#m( ) power ON interrupt HW Processors, Memory, Storage, Network, Sensors, Actuators 9

10 Execution Flow without OS Simple Scheduler Structure task_#1( ) task_#2( ) SW wait( ) interrupt( ) schedule( ) task_#3( ) bootstrap( ) task_#n( ) power ON interrupt HW Processors, Memory, Storage, Network, Sensors, Actuators 10

Protection OS protects the system from many types of application faults Example: separation of each program s memory space Determine the range of legal

11 Protection OS protects the system from many types of application faults Example: separation of each program s memory space Determine the range of legal addresses Base register holds the smallest legal memory address. Limit register contains the size of the range Memory outside the defined range is protected 11

12 Use of A Base and Limit Register 12

13 Hardware Address Protection 13

Task A Task B Task C Task D Task A (weight 25.0%) time Task B (weight 12.

14 Illusion Make hardware limitations go away As if there are infinite number of processors (time sharing) As if there is extremely large memory (virtual memory) Task A Task B Task C Task D Task A (weight 25.0%) time Task B (weight 12.5%) Task C (weight 50.0%) Task D (weight 12.5%) Time Shared Multitasking Virtual Memory 14

15 Coordination and Optimization Make many things work together efficiently Concurrency Multitasking (synchronization and scheduling) Multi-user support Multithreading Efficiency Overlapped I/O and Processing I/O devices and the CPU can execute concurrently Effective storage management Caching, paging, and swapping Fast interrupt handling 15

16 Multitasking and Synchronization 아들아냉장고에카레있다. 엄마 우리헤어져!! 잘먹고잘살아라!! 여자친구 Without synchronization write With synchronization 아들아우리헤어져!! 냉장고에카레잘먹고잘살아라!! 있다. 여자친구엄마 아들아냉장고에카레있다. 엄마우리헤어져!! 잘먹고잘살아라!! 여자친구 16

17 Multitasking and Scheduling 도착알림 메세지도착 도착알림 메세지도착 17

18 II. Evolution of OS

19 What is the First Computer? From B.C 4000 Input and Output Physical movements by hands and read by eyes No programming and no special I/O devices Very volatile memory and slow Abacus! The first hand-held computer? 19

20 The ENIAC (1946) The first computer that uses electricity Technology Vacuum tubes Floor space 1,000 square feet Weight 30 tons Input/Output Cards, lights, switches Human operators Speed Less than 5,000 operations per second 20

21 The History of Computers and OS Why history? Hard to define and explain the notion of operating system Learning about the OS history will help you understand what it is and how it works Three phases of History Phase I: early 50s late 60s Mainframe computers Monitor + human operators Phase II: late 60s late 90s (modern OS concepts) Minicomputers and personal computers Advent of UNIX Phase III: late 90s present (mobile, cloud, and multicore) 21

22 Phase I. Mainframe Computers From 1960s to 1970s Technology Transistors Input devices Panel switches, paper tape, punched cards Card readers, magnetic tape Output devices Display lights on the console Line printers 22

23 Human Operators Cost vs. performance of mainframes Computers were very expensive $750,000 plus $185,000 for a high speed printer Humans were cheap Significant amount of setup time Human programmer/operator Program, setup, monitor, and debug Significant amount of setup time 23

Resident Monitor A resident monitor can be considered a primitive precursor to the operating system It governed the machine before and after each job

24 Resident Monitor A resident monitor can be considered a primitive precursor to the operating system It governed the machine before and after each job control card was executed, loaded and interpreted each control card, and acted as a job sequencer for batch processing operations Resident Monitor 24

I/O operation CPU is switched to another job Benefit Increase of CPU utilization

25 Multiprogrammed Batch Systems Several jobs are kept in main memory at the same time CPU is multiplexed among them Eventually a job may have to wait for some task such as I/O operation CPU is switched to another job Benefit Increase of CPU utilization Reduction of CPU idle time Job scheduling is required When multiple programs are ready IBM

26 Spooling Emergence of faster I/O devices Slow mechanical devices Card reader -> CPU -> line printer Fast magnetic devices Card reader -> tape drives -> CPU -> tape drives -> line printer Performance improvement by Spooling Simultaneous Peripheral Operation On-Line Spooling overlaps I/O and computation 26

27 Phase II. Modern Computers Since late 1960s With the advent of microprocessor chips Minicomputers, workstations, and personal computers 27

28 UNIX Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix Development started in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others The pre-history of Unix dates back to the mid-1960s MIT, Bell Labs, and General Electric were developing an innovative time-sharing operating system called Multics for the GE-645 mainframe Multics introduced many innovations, but had many problems (the size and complexity) Bell Labs slowly pulled out of the project and decided to redo the work on a much smaller scale 28

29 UNIX (Phase II) 29

30 Multitasking and Multi Users Multi-programming and multi-tasking Several programs are kept in main memory They run at the same time (time-sharing) Interactive and on-line system User enters a command and the system executes them The system seeks the next control statement from the user s keyboard or mouse Multi-user environment Different users can use the computer at the same time 30

Personal Computers Personal computers such as the Atari 800,

history of the personal computer as a massmarket consumer

Personal Computer that coined both the term Personal Computer

31 Personal Computers Personal computers such as the Atari 800, released in 1978, and the BBC Micro, released in 1981 The history of the personal computer as a massmarket consumer electronic device began in 1981 with the launch of the IBM Personal Computer that coined both the term Personal Computer and PC Atari 800 (1978) Xerox Alto (1973) Apple II (1977) IBM 5150 (1981) 31

a graphical user interface (GUI), concepts first introduced by

32 Mouse and GUI The Xerox Alto, developed at Xerox PARC in 1973, was the first computer to use a mouse, the desktop metaphor, and a graphical user interface (GUI), concepts first introduced by Douglas Engelbart Xerox Alto (1973) Atari ST (1985) Windows 1.0 (1985) 32

Internet and WWW ARPANET was the precursor network for academic and military purposes (1980s) NSF funding and private funding led to worldwide participation in the Internet The

33 Internet and WWW ARPANET was the precursor network for academic and military purposes (1980s) NSF funding and private funding led to worldwide participation in the Internet The World Wide Web is the primary application A NeXT Computer was used by Tim Berners-Lee at CERN and became the world's first Web server (1991) The first Web server (HTTP daemon) 33

connectivity Battery-operated Motorola DynaTAC

34 Phase III. Mobile, Cloud, and Multicore The first PDA was released in 1984 by Psion, the Organizer Typical features Touch screens and memory cards Wireless connectivity Battery-operated Motorola DynaTAC (1984) Palm TX (2005) Mobile OSes Palm OS Microsoft Windows Mobile with a Windows CE kernel Apple iphone (2007) 34

35 Windows CE 35

original ARPANET by as early as 1977 and the CSNET by 1981 The popularization of

36 Cloud Computing The origin of the term cloud computing in computing is unclear The cloud symbol was used to represent networks of computing equipment in the original ARPANET by as early as 1977 and the CSNET by 1981 The popularization of the term can be traced to 2006 when Amazon.com introduced its Elastic Compute Cloud 36

Multicore Computing Released in 2001, the POWER4 was a multicore

non-embedded microprocessor In October 2011, a heterogeneous

little, was announced by ARM Holdings Linux kernel version 2.

37 Multicore Computing Released in 2001, the POWER4 was a multicore microprocessor, with two cores on a single die, the first non-embedded microprocessor In October 2011, a heterogeneous computing architecture, called big.little, was announced by ARM Holdings Linux kernel version 2.0 was released in 1996, the major feature of 2.0 was multiprocessor support POWER4 big.little Apple A5 37

38 Migration of Operating-System Concepts and Features 38

39 39

Introduction to Computer Systems and Operating Systems

Introduction to Computer Systems and Operating Systems Minsoo Ryu Real-Time Computing and Communications Lab. Hanyang University msryu@hanyang.ac.kr Topics Covered 1. Computer History 2. Computer System