SWE202 Fundamental of Operating System Lecture 1: Introduction Asst.Prof.Dr.Surasak Mungsing Faculty of Information Technology Sripatum University

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

Evolution of Computers History of computing The first generation The second generation The third generation The fourth generation The fifth generation

What is a Computer Automated electronic device Computing machine Able to solve simple or complex problems based on mathematics

History of computation Abacus

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

The first generation of computer vacuum tube ENIAC (Electronic Numerical Integrator and Calculator) built by the University of Pennsylvania in More Info at:

The second generation computer transistors Punched card Magnetic tape

The 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 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 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 computer Ultra large-scale integration Notebook, PDA, smart phone OS หลากหลาย เช่น MS Windows, MacOS, Linux, etc

Operating Systems

Importance 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 Systems (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 Systems The zeroth generation The first generation The second generation The third generation The fourth generation

The zeroth generation of OS 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 OS 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 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 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 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 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 Systems Program execution Input/Output processing File systems management Communication Error detection Resource allocation User accounting Security system

Program 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 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 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

Communication Data communication help enhance utilization of computers Data communication between computers handled by network operating system

Error 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 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 accounting Audit trail System Administration policy Accessing right to computer and computer networks Attack behavior under authorized users

Security 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&A

Questions Describe characteristics of the following OS  Batch  Time-sharing  Real-time  Distributed ระบบการทำงานของคอมพิวเตอร์ในปัจจุบัน มีการ เพิ่มขั้นตอนการเข้ารหัสตั้งแต่เริ่มเข้าสู่ระบบ ส่ง ข้อมูลผ่านเครือข่าย หรือแม้แต่บันทึกข้อมูลลง แฟ้ม จงให้เหตุผลเชิงวิชาการและเทคนิคการทำ ให้เกิดผล (implementation) ว่ามีข้อดี / ข้อเสียอย่างไรใน การประยุกต์วิธีเข้ารหัสลับ