silberschatz, galvin and gagne 2002 1.1 operating system concepts chapter 1: introduction what is...

Silberschatz, Galvin and Gagne 20021.1Operating System Concepts

Chapter 1: Introduction

What is an Operating System? Mainframe Systems Desktop Systems Multiprocessor Systems Distributed Systems Clustered System Real -Time Systems Handheld Systems Computing Environments


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 and make solving user problems easier. Make the computer system convenient to use.

Use the computer hardware in an efficient manner.


Computer System Components

1. Hardware – provides basic computing resources (CPU, memory, I/O devices).

2. Operating system – controls and coordinates the use of the hardware among the various application programs for the various users.

3. Applications programs – define the ways in which the system resources are used to solve the computing problems of the users (compilers, database systems, video games, business programs).

4. Users (people, machines, other computers).


CPU

Number crunsh

Data shuffle


CPU

CISC

complex instruction set computer

RISC

reduced instruction set computer


CPU

micro-CODE

Beräknings instr.

Kontroll instr.


CPU

ALU // FPU

Heltal // Flyttal


Register

Data och Adress register

Seg.P. Seqment pointer

PC program counter

IR Instruktions reg.

SP stackpekare

CC Condision Code reg.( flags)


Instruktioner ASEMBLER

Instruktioner

JMP - JUMP to “adr”

Fetch “adr” till “reg: A”

Fetch “adr” till reg: B”

Add “reg:A med Reg:B lägg svaret i “Reg C”

Mov Reg: C till adr:


Språkbinär kod- maskin språk

---------------------------------

Assembler kod

----------------------------------

C, Fortran, Pascal, Cobol.

----------------------------------

Smaltalk , JAVA,

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Kod generatorer


INTEL x86 /CICS

8080

8088

8086

80286

8087

80287

80386

80387

80486

387

586PentiumII, III IV


SPARC / risc

en Öppen Konstruktion

ISA Instruction Set Architectur

ROSS,Weitech, Texas, Cypress Fujitsu

SuperscalärSparc 1 (32/16

Sparc 2 (32/16)

Micro Sparc (32)

Hyper Sparc (32)

Super Sparc (32)

Ultra Sparc (64)


Superscalär

Multipla CPUer i samma skal

separata delar utför hämtning/återlämning av inst. o.data

utför förarbete ex: beräkna adresser

se vidare på: www.pcworld.com/jul00/cpus

http://www.intel.com/home/pentium4/


Hyper - Threading

INTEL P4 (2,8Ghz)

http://www.intel.com/info/hyperthreading/


Addressbus

Data bus A ddress

bus

Data bus

MINNECPU

Add re ss

bus

Data bu s

Grafik/

Add ress

bus

Da ta bu s

DISK

Data busAd dre ss

bus

Tangentbord

Video

8 / 16 bit “ISA bus”


PCI brige MinneCPU

cache

PCI/ISAbrige

Videocontroller

Networkcontroller

SCSIcontroller

7 el. 14

IDE/PCI contr.max 2

IDE/ISA Printer, modem, ljud


Abstract View of System Components


Operating System Definitions

Resource allocator – manages and allocates resources. Control program – controls the execution of user programs

and operations of I/O devices . Kernel – the one program running at all times (all else being

application programs).


Mainframe Systems

Reduce setup time by batching similar jobs Automatic job sequencing – automatically transfers control

from one job to another. First rudimentary operating system. Resident monitor

initial control in monitor control transfers to job when job completes control transfers pack to monitor


Memory Layout for a Simple Batch System


Multiprogrammed Batch Systems

Several jobs are kept in main memory at the same time, and the CPU is multiplexed among them.


OS Features Needed for Multiprogramming

I/O routine supplied by the system. Memory management – the system must allocate the memory

to several jobs. CPU scheduling – the system must choose among several

jobs ready to run. Allocation of devices.


Time-Sharing Systems–Interactive Computing

The CPU is multiplexed among several jobs that are kept in memory and on disk (the CPU is allocated to a job only if the job is in memory).

A job swapped in and out of memory to the disk. On-line communication between the user and the system is

provided; when the operating system finishes the execution of one command, it seeks the next “control statement” from the user’s keyboard.

On-line system must be available for users to access data and code.


Desktop Systems

Personal computers – computer system dedicated to a single user.

I/O devices – keyboards, mice, display screens, small printers. User convenience and responsiveness. Can adopt technology developed for larger operating system’

often individuals have sole use of computer and do not need advanced CPU utilization of protection features.

May run several different types of operating systems (Windows, MacOS, UNIX, Linux)


Parallel Systems

Multiprocessor systems with more than on CPU in close communication.

Tightly coupled system – processors share memory and a clock; communication usually takes place through the shared memory.

Advantages of parallel system: Increased throughput Economical Increased reliability

graceful degradation fail-soft systems


Parallel Systems (Cont.)

Symmetric multiprocessing (SMP) Each processor runs and identical copy of the operating system. Many processes can run at once without performance

deterioration. Most modern operating systems support SMP

Asymmetric multiprocessing Each processor is assigned a specific task; master processor

schedules and allocated work to slave processors. More common in extremely large systems


Symmetric Multiprocessing Architecture


Multi CPU maskiner

Multiprocessing

betyder att olika processer kan processas simultant.

MAO. en maskin med 8 cpu kan exec. 8 processer som tillhör olika program, eller

olika processer i samma program.


Multi CPU maskiner

Asymetriska

Symetriska

Löst-kopplade

Tät-kopplade


Asymetriska

Kärnan kör på CPU 0

All disk I/O kör på CPU 1

Allt trafik till från nätverker går på CPU 2


Symetriska

Alla CPUer är värda lika mycket,

processerna kan vandra runt bland CPU-erna.


Loosely Coupled,

varje CPU har eget minne.

minnes accesser sker över en för varje cpu dedicerad mines bus.

I/O sker över en System bus.

Detta ger en snabb maskin.

“Shared memmory” är svårt att genomföra.

CPU

Minne Minne Minne Minne

CPU CPUI/O Controler kort


Tightly Coupled

Alla CPU delar minnet/ minnes bus.

Cpuerna kan skick interupt till annan cpu,

de kan även kommunisera via shared memory

CPU

Minne Minne Minne Minne

CPU CPU CPUI/O Controler kort


Distributed Systems

Distribute the computation among several physical processors. Loosely coupled system – each processor has its own local

memory; processors communicate with one another through various communications lines, such as high-speed buses or telephone lines.

Advantages of distributed systems. Resources Sharing Computation speed up – load sharing Reliability Communications


Distributed Systems (cont)

Requires networking infrastructure. Local area networks (LAN) or Wide area networks (WAN) May be either client-server or peer-to-peer systems.


General Structure of Client-Server


Clustered Systems

Clustering allows two or more systems to share storage. Provides high reliability. Asymmetric clustering: one server runs the application while

other servers standby. Symmetric clustering: all N hosts are running the application.


Real-Time Systems

Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems.

Well-defined fixed-time constraints. Real-Time systems may be either hard or soft real-time.


Real-Time Systems (Cont.)

Hard real-time: Secondary storage limited or absent, data stored in short term

memory, or read-only memory (ROM) Conflicts with time-sharing systems, not supported by general-

purpose operating systems.

Soft real-time Limited utility in industrial control of robotics Useful in applications (multimedia, virtual reality) requiring

advanced operating-system features.


Handheld Systems

Personal Digital Assistants (PDAs) Cellular telephones Issues:

Limited memory Slow processors Small display screens.


Migration of Operating-System Concepts and Features


Computing Environments

Traditional computing Web-Based Computing Embedded Computing

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