SWE202 Fundamental of Operating SystemSWE202 Fundamental of Operating System

Lecture 1: IntroductionLecture 1: Introduction

Asst.Prof.Dr.Surasak MungsingAsst.Prof.Dr.Surasak MungsingFaculty of Information TechnologyFaculty of Information Technology

Sripatum UniversitySripatum University

TopicTopic

• Basic Knowledge of computers• Importance of Operating Systems• Evolution of Operating Systems• Responsibility of Operating Systems

Evolution of ComputersEvolution of Computers

• History of computing• The first generation• The second generation• The third generation• The fourth generation• The fifth generation

What is a ComputerWhat is a Computer

• Automated electronic device• Computing machine• Able to solve simple or complex problems

based on mathematics

History of computationHistory of computation

• Abacus

http://www.youtube.com/watch?v=yfWoR3IJh2A

• Chinese abucus

$26 online step-by-step how to perform addition, subtraction, division, multiplication, square roots and cube roots on a Chinese abacus

The first generation of computerThe first generation of computer

vacuum tubeENIAC (Electronic Numerical Integrator and Calculator) built by the University of Pennsylvania in 1943-45

More Info at: http://www1.fccj.org/jdebo/new_page_3.htm

The second generation computerThe second generation computer

transistors

Punched card Magnetic tape

The second generation computerThe second generation computer

• Transistor era• low cost, low power consumption, low heat

produced• Transistor-based computer• Processing speed in milliseconds per instruction• Store data in punched cards and magnetic tapes• Use assembly language

The third generation of computerThe third generation of computer

• IC-Integrated Circuit era• An IC can contain 100,000 circuit in this period• 1 KB RAM, Intel 4004 (4-bit) and Intel 8008 (8-bit)

used in small electronic devices such as normal calculators, watches, scales, etc.

• Processing power in microseconds per instructions

• High-level programming languages• RDBMS

The fourth generation of computerThe fourth generation of computer

• LSI (Large-scale integration) and VLSI (very large-scale integration)

• Personal Computer or PC era• Processing capability: nanoseconds per

instruction• Pointing device (e.g. mouse click) introduced

The fifth generation of computerThe fifth generation of computer

• Ultra large-scale integration

• Notebook, PDA, smart phone

• OS หลากหลาย เช่�น MS Windows, MacOS, Linux, etc

Operating SystemsOperating Systems

Importance of Operating SystemsImportance of Operating Systems

1. It moderates the relationship between the computer and its peripherals

2. It helps in the management of files,- copying, deleting, moving of files from one storage location to the other.

3. It encourages the memory for its efficient usage and thus adding the speed of the computer.

Importance of Operating SystemsImportance of Operating Systems(cont.)(cont.)

4. It manages the activities of the processor in terms of job execution according to the priority of arrival , of jobs

5. It informs the user of any hardware or software error

6. It makes communication between the computer and the user or the operator possible

Evolution of Operating SystemsEvolution of Operating Systems

• The zeroth generation• The first generation• The second generation• The third generation• The fourth generation

The zeroth generation of OSThe zeroth generation of OS

• 1940-1949 • switches controlled directly by users• Controlled by machine language (0 or 1 or

binary)• no concept of software (no computer

program) only use hardware control

The first generation of OSThe first generation of OS

• 1950-1959• batch processing• batch job controlled computer operations and

then handled control to OS after job completion

• Responsibility of OS was to set up computer to be ready for the next batch job

The second generation of OSThe second generation of OS

• beginning of 1960’s• multiprogramming• multiprocessing• multitasking• single CPU• OS-user interface development• time-sharing (both interactive mode and

batch mode)

The third generation of OSThe third generation of OS

• late 1960’s – beginning of 1970• general-purpose operating systems• the end of monolithic programming • operating system layer• device driver to directly control hardware

The fourth generation of OSThe fourth generation of OS

• After 1970’s• Personal computer (PC) invention• on-line data demand via personal computers and

computer network• size of OS was reduced to core OS that was

necessary to only computer• Break into independent subsystems, e.g. file systems,

memory management, process management, I/O system, etc. and utilities programs such as database system and virtual machine

Variety of OSVariety of OS

• new architectures require more specific OS• connectivity applications (LAN, WAN,

distributed processing, parallel distributed processing, real-time operating systems) need modular program as plug-and-play

Responsibility of Operating SystemsResponsibility of Operating Systems

• Program execution• Input/Output processing• File systems management• Communication• Error detection• Resource allocation• User accounting• Security system

Program executionProgram execution

• Program load scheduling• Program execution from beginning to end• Normal termination and abnormal

termination• Protecting ripple effects to other program

loading into memory or other resource such as files, hardware, network etc.

Input/Output processingInput/Output processing

• Provide facility for receiving and sending data from and to external system

• Communicate with Input/Output devices through drivers

• Protecting and ensuring correctness and integrity of data at all time of program execution

File systems managementFile systems management

• Permanent store of data• File creating, storing, updating, and deleting

are normally accomplished by user software• Users don’t know where in physical memory

their files stored

CommunicationCommunication

• Data communication help enhance utilization of computers

• Data communication between computers handled by network operating system

Error detectionError detection

• OS detects errors during program execution at all time to maintain data integrity

• Erros may be caused by program, computer architecture physical limitations, power supply system, attackers

• Examples of errors – trying to write data in write-protect section of memory, divide by zero, overflow in control register etc.

Resource allocationResource allocation

• OS responsible for fair resource allocation to support execution of user programs, utility programs, or OS program according to design policy of OS designer

• Also avoid and prevent problems in competing for limited resources of user program and OS program, e.g. deadlocks and trashing

User accountingUser accounting

• Audit trail• System Administration policy• Accessing right to computer and computer

networks• Attack behavior under authorized users

Security systemSecurity system

• Security is important, especially, in multiuser system

• Access rights or privileges for using resources, utility programs, and communication through computer network must be controlled

• Examples of computer and data security: firewall installation, data encryption, etc.

Q&AQ&A

QuestionsQuestions• Describe characteristics of the following OS

Batch Time-sharing Real-time Distributed

• ระบบการทำ�างานของคอมพิ�วเตอร�ในปั�จจ�บ�น ม�การเพิ��มข��นตอนการเข�ารหั�สต��งแต"เร��มเข�าส#"ระบบ ส"งข�อม#ลผ่"านเคร&อข"าย หัร&อแม�แต"บ�นทำ(กข�อม#ลลงแฟ้*ม จงใหั�เหัต�ผ่ลเชิ�งว�ชิาการและเทำคน�คการทำ�าใหั�เก�ดผ่ล (implementation) ว"าม�ข�อด�/ข�อเส�ยอย"างไรในการปัระย�กต�ว�ธี�เข�ารหั�สล�บ