Operating System

Chap. 1) Introduction

경희대학교 컴퓨터공학과

조 진 성

Operating System 1

Computer ?

PersonalComputer

EmbeddedComputer

ServerComputer

Computer SW

Computer HW

Operating System 2

Computer ?　 Computer system components (Abstract view)

Operating System 3

Computer ?　 Computer system organization

Operating System 4

Computer ?　 Modern PC architecture

MemoryControllerHub (MCH)

I/OControllerHub (ICH)

Operating System 5

Operating Systems ?　 OS is a resource manager

Abstraction Sharing

Time multiplexing Space multiplexing

Protection Fairness Performance

　 Definition in textbook Resource allocator Control program Kernel

CPU Memory I/O devices …

Resources

SW which manages ‘Computer HW’ resources for

1) convenience2) efficiency

Operating System 6

Computer System Operation　 Computer HW architecture (Abstract view)

Generalpurposeregisters

PSWSPIRPC

MMU

ALU

CU

Memory

I/O device I/O device…

Bus

Operating System 7

Computer System Operation　 CPU operation

Von Neumann architecture

Instructions Arithmetic instructions: add, subtract, multiply, divide, … Logical instructions: and, or, xor, not, shift, … Control flow instructions: goto, if, call, return, … Data instructions: load, store, move, input, output, …

Operating System 8

Computer System Operation　 Bootstrapping in Linux

The CPU initializes itself and then execute an instruction at a fixed location (0xfffffff0).

This instruction jumps into the BIOS/UEFI. BIOS (Basic Input/Output System) UEFI (Unified Extensible Firmware Interface)

The BIOS/UEFI finds a boot device and fetches Boot Loader(LILO/GRUB). MBR (Master Boot Record) in BIOS ESP (Efi System Partition) in UEFI

The BIOS/UEFI loads and transfers control to LILO/GRUB. LILO/GRUB loads the compressed kernel. The compressed kernel decompresses itself and transfers control to the

uncompressed kernel.

Operating System 9

Computer System Operation　 CPU

Instruction Set Architecture (ISA) CISC vs. RISC Intel, SPARC, MIPS, PowerPC, ARM, Alpha, …

Pipelining Fetch, Decode, Execute, Write Back, etc.

Instruction-Level Parallelism (ILP) Superscalar vs. VLIW Simultaneous multithreading Multi-core

Operating System 10

Computer System Operation　 Multi-core architecture

Operating System 11

Computer System Operation　 Symmetric multiprocessing architecture

Cf) NUMA (Non-Uniform Memory Access) multiprocessing architecture

Operating System 12

Computer System Operation　 Clustered system architecture

Cf) Parallel vs. Distributed system

Operating System 13

Computer System Operation　 I/O operation

I/O request via I/O instruction Direct I/O vs. Memory-mapped I/O Communicates with registers in I/O controller Typically, IR (Instruction Register) & DR (Data Register)

I/O method Programmed I/O Interrupt DMA (Direct Memory Access)

Operating System 14

Computer System Operation　 Interrupt-driven I/O cycle

Operating System 15

Computer System Operation　 I/O mode from the perspective of application processes

Asynchronous/Non-blocking

Synchronous/Blocking

Operating System 16

Computer System Operation　 Interrupt

Generated by hardware devices (asynchronous) E.g.) timer interrupt, keyboard interrupt, etc.

　 Trap Generated by application processes (synchronous) E.g.) system calls

　 Fault (Exception) Generated by CPU instructions (synchronous) Divide-by-zero, page fault, protection fault, etc.

　 Hardware interrupt vs. Software interrupt

Operating System 17

Computer System Operation　 Six steps process to perform DMA transfer

Operating System 18

Computer System Operation　 Storage hierarchy

• ROM vs. RAM• SRAM vs. DRAM

Operating System 19

Computer System Operation　 Memory hierarchy

　 Caching Cache management policy

Write-through vs. Write-back Cache coherency

Operating System 20

Computer System Operation　 Physical hard disk structure (HDD)

platters surfaces tracks sectors cylinders arm heads

platter

surface

track sector

cylinder

arm

head

Operating System 21

Computer System Operation　 Compact Flash card internals (SSD)

Processing Unit: FTL(Flash Translation Layer)

FlashController NAND Flash

Memory

DataIN/OUT

Control

ARMcore SRAM NOR

HOSTDMA0/1

Operating System 22

Computer System Operation　 System call

Cf) Function call

user modekernel mode

httpd: read( )

trap to kernel mode; save app state

find read( ) handler in vector table

restore app state, return to

user mode, resume

trap handler

read( ) kernel routine

Operating System 23

Computer System Operation　 Hardware protection

CPU protection Timer (periodic interrupt, 10ms in Linux)

Memory protection Protection fault (E.g. segmentation violation in Linux)

I/O protection Dual mode operation in CPU Privileged instructions only in kernel mode

Operating System 24

Computer System Operation　 OS takes control of the system

Bootstrapping

System calls

Interrupts

Hardware

trap

interrupts

System call

Operating System 25

Computer History　 1st Generation (1945-55)

Vacuum Tubes and Plugboards

No OS No Programming Languages No Assembly Languages

Operating System 26

Computer History　 2nd Generation (1955-65)

Transistors and Mainframes

Batch systems OS is called “Resident Monitor” CPU is underutilized due to the bottleneck in I/O

Operating System 27

Computer History　 3rd Generation (1965-80)

Integrated Circuits (ICs)

Architectural advances The notion of “Computer Architecture” IBM System/360 family

Multiprogramming systems Increased CPU utilization

Time-sharing systems Improved response time Traditional OS features

Operating System 28

Computer History　 4th Generation (1980-)

LSIs & VLSIs

Architectural advances Microprocessors: smaller and faster Storages: larger and faster CPU work is offloaded to I/O devices Personal computers (Desktop system)

Modern OS Features GUI (Graphical User Interface) Multimedia Internet & Web Networked / Distributed, etc.

Operating System 29

Computing Environments　 Traditional computing

Mainframe system Batch system Multiprogramming system Time-sharing system

Desktop system

　 Mobile computing Hand-held system

Limited memory Slow processors Small display screens

　 Real-time embedded computing Real-time systems

Hard real-time vs. Soft real-time Embedded systems

Operating System 30

Computing Environments　 Client-server computing

Large-scale server in data center Clustered server

Parallel + Distributed + Storage

Operating System 31

Computing Environments　 Peer-to-peer computing

Discovery protocol Napster, Gnutella, VoIP, etc.

　 Cloud computing Infrastructure as a Service (IaaS) Platform as a Service (PaaS) Software as a Service (SaaS)

Operating System 32

Computing Environments　 Virtualization

VMM or Hypervisor

Non-virtual Machine Virtual Machine

Operating System 33

Computing Environments　 Virtual machine examples

　 Java JVM executes “platform-neutral byte-codes” JIT (Just-In-Time) compilers increase performance

Hardware

Windows

WindowsProcesses

VMWare

Linux

LinuxProcesses

Hardware

Mac OS X

MacProcesses

Parallels

Windows

WindowsProcesses

Parallels

Linux

LinuxProcesses

JVM

JavaThreads

JVM

JavaThreads

Operating System 34

Computing Environments　 Distributed computing

Collection of separate, possibly heterogeneous, systems networked together Network operating systems provides illusion of a single system E.g.) Hadoop

Operating System 35

OS HistoryA long time ago,

in a galaxy far, far away, …

　 IBM OS/360: Multiprogramming

　 MIT CTSS (Compatible Time-Sharing System)

　 MIT, Bell Labs, GE, MULTICS(MULTiplexed Information and Computing Service)

And Unix was born in 1969

Operating System 36

OS History: Unix (1969-85)

USG/USDL/ATTISDSG/USO/USL

Bell LaboratoriesResearch

Berkeley SoftwareDistributions

1969 First Edition

1973 Fifth Edition

1976 Sixth Edition

1977 PWB MERT CB UNIX 1BSD

1977 UNIX RT Seventh Edition 2BSD

32V

1979 3BSD

3.0 4.0BSD

1980 XENIX 3.0.1

1981 4.0.1 4.1BSD

1982 5.0 Sys tem III 4.1aBSD

1983 5.2 Sys tem V XENIX 3 Eighth 4.1cBSDEdition

2.9BSD

2.8BSD

1984 Sys tem V SunOS 4.2BSDRelease 2

1985

Figure 1.1 The UNIX system family tree, 1969-1985

Operating System 37

OS History: Unix (1985-96)

System V Eighth1985 Release 2 XENIX 3 SunOS Edition 4.2BSD 2.9BSD

1986 MACH 4.3BSD

Sys tem V1987 Release 3 Ninth 2.10BSD Chorus Edition

XENIX 5

1988 MACH 2.5 4.3BSD-Tahoe

Sys tem V1989 Release 4 NeXT SunOS4 Tenth 2.11BSD

Step Edit ion

SunOS3

Chorus NET/1 V3

1990 OSF/1 Plan 9 4.3BSD-Reno

1991 NET/2

386BSD

1992 Solaris NetBSD 0.8

DEC UNIX BSDI 1.0 FreeBSD 1.0 Novell1993 Linux UNIX Solaris 2

Ware 4.4BSD

1994 4.4BSD Lite-1

1995 SCO FreeBSD 2.0 BSDI 2.0 UNIX 4.4BSD

Lite-21996

Figure 1.2 The UNIX system family tree, 1986-1996

Operating System 38

OS History: Unix (1997-)　 Sun Solaris　 HP HP-UX　 IBM AIX　 Caldera (SCO) Unixware　 Compaq (Digital) Tru64　 SGI Irix　 Linux, FreeBSD, NetBSD　 Apple Mac OS X, etc.

　 Cf) POSIX

Operating System 39

OS History: Windows & Linux

1.0 2.0 3.0 3.2 4.0

3.0 3.1

5.0 6.0

3.1 3.51

7.0

95

4.0

98

2K XP

1981 82 84 86 88 90 91 93 94 95 98 00 01

ME

0.01 0.99 1.0 1.2 2.0

96 97 99

1.0

92

98SE2.0

3.1 3.11

2.1 2.2 2.4

MS-DOS Family

Windows Family

Windows for WorkGroup Family

Windows NT Family

Linux

Operating System 40

OS History: Windows & Linux

07 09

2.6.33

10 15

A.B.CA: Kernel versionB: Major revisionC: Minor revision

04

2.6.0

Windows 8

12

3.2.0 4.4.0

Operating System 41

OS History: Linux　 1983

Richard Stallman, GNU project and free software concept gcc, gdb, glibc, and other tools

　 1991 Linus Tovalds, Linux kernel project Completely free operating system: Linux/GNU

　 1995 Linux is more and more popular on server systems

　 2000 Linux is more and more popular on embedded systems

　 2008 Linux is more and more popular on mobile devices

　 2010 Linux is more and more popular on phones

Operating System 42

OS History: Linux　 Television

　 Personal router

　 PoS (Point of Sales) terminal

　 Laser cutting machine

　 Viticulture machine

Operating System 43

OS History: Taxonomy 　 Mainframe systems

CTS, MULTICS, IBM MVS, VM　 Desktop systems

DOS, Windows, MacOS, Unix/Linux　 Distributed systems

Amoeba(Vrije Univ.), Locus(UCLA), Grapevine(Xerox), V(Stanford), Eden(U. of Washington), Chorus/Nucleus(Inria)

　 Embedded systems Vertex, pSOS, VxWorks, OSE, Windows-CE, Embedded Linux Company-proprietary OS (Cisco, Qualcomm, Palm, Cellvic)

　 Real-time systems Real-Time Linux, Spring(U. of Massachusetts), HARTS(U. of Michigan),

MARUTI(U. of Maryland)