Operating Systems. Rafael Ramirez (T, S)

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1 Operating Systems Rafael Ramirez (T, S) Sergio Giraldo(P, S) Matteo Segnorini (P, S) T=Teoria; S=Seminarios; P=Prácticas Operating Systems Introduction Slide 1

edu Matteo Segnorini (P, S) matteo.segnorini@upf.

2 Operating Systems Calendario Curso en: Ø Web de la ESUP Operating Systems Introduction Slide 2

3 Operating Systems Topics: 1. Operating System introduction - Introduction, operating system components, types of systems, 2. Process Management - Processes & threads, process synchronization, CPU scheduling, 3. Memory Management - Main Memory, virtual memory 4. Storage Management - File-system interface, file-system implementation 5. I/O systems & security - I/O hardware, application I/O interface, security threats Operating Systems Introduction Slide 3

Process Management - Processes & threads, process synchronization, CPU scheduling, 3.

4 Operating Systems Evaluation: Examen teoría 60% Prácticas 30% se ha de aprobar tanto teoria como prác/sem Seminarios 10% Prácticas = (0.6 * practicas) + (0.4 * examen de prácticas) se ha de aprobar tanto prac-examen como prácticas Participación Operating Systems Introduction Slide 4

5 Operating Systems Operating Systems Introduction Slide 5

6 Operating Systems Seminarios (4): grupos de 2-4 Prácticas (5): grupos de 2 Operating Systems Introduction Slide 6

7 Operating Systems Course Book: A. Silberschatz, P.B. Galvin, G. Gagne. Fundamentos de sistemas operativos. McGraw Hill, Other books: W. Stallings. Sistemas operativos : aspectos internos y principios de diseño, Prentice Hall L. Duran-Rodriguez. Sistemas operativos: referencia bàsica. Marcombo, A.S. Tanenbaum, Modern operating systems. Prentice Hall, Operating Systems Introduction Slide 7

Sistemas operativos : aspectos internos y principios de diseño, Prentice Hall 2005. L. Duran-Rodriguez.

8 Operating Systems Contact: q Clase q Seminarios/Prácticas q q Horas oficina: Cualquier dia (previa cita) q Anuncios, documentacion, q Moodle + Operating Systems Introduction Slide 8

9 Introduction Chapter 1 & 2 - Course Book OS Introduction Slide 9

10 What is an Operating System? OS Introduction Slide 10

11 What is an OS? OS Introduction Slide 11

12 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: l Execute user programs and make solving user problems easier. l Make the computer system convenient to use. " Use the computer hardware in an efficient manner. OS Introduction Slide 12

13 Types of Operating Systems? " OS for Batch systems " Time-shared OS (multiprogramming) l Why multiprogramming? l OS features needed for multiprogramming? " Desktop OS convenience/responsiveness? " OS for Parallel systems l Tightly coupled system l Throughput? Economy? Reliability? l Symmetric/asymmetric multiprocessing? OS Introduction Slide 13

l OS features needed for multiprogramming? " Desktop OS convenience/responsiveness?

14 Types of Operating Systems? " OS for Distributed systems l Loosely coupled system LAN & WAN " Real-time OS l time constraints l Soft real-time l Hard real-time " Hand-held OS l Limitations OS Introduction Slide 14

15 Common System Components A system as large and complex as an OS can be created only by partitioning it into smaller pieces " Process Management " Main Memory Management " Secondary Storage Management " File Management " I/O System Management " Protection System " OS Structures Slide 15

Management " Main Memory Management " Secondary Storage Management "

16 System Calls " System calls provide the interface between a running program and the operating system. l For example open input file, create output file, print message to console, terminate with error or normally l Generally available as routines written in C and C++ " Mostly accessed by programs via a high-level Application Program Interface (API) rather than direct system call use l Provides portability (underlying hardware handled by OS) l Hides the detail from the programmer " Win32 API for Windows " POSIX API for UNIX, Linux, and Mac OS X " Java API for the Java virtual machine (JVM) OS Structures Slide 16

C and C++ " Mostly accessed by programs via a high-level Application Program Interface (API) rather than direct system call use l Provides portability

17 API System Call OS Relationship OS Structures Slide 17

18 Standard C Library Example " C program invoking printf() library call, which calls write() system call OS Structures Slide 18

19 System Call Parameter Passing " Three general methods used to pass parameters to the OS l Simplest: pass the parameters in registers? l Parameters stored in a block, or table, in memory, and address of block passed as a parameter in a register l Parameters placed, or pushed, onto the stack by the program and popped off the stack by the operating system OS Structures Slide 19

l Parameters stored in a block, or table, in memory, and address of block passed as a

20 OS Design Implementation " Mechanisms determine how to do something, policies decide what will be done. " The separation of policy from mechanism is a very important principle in designing OSs l It allows maximum flexibility if policy decisions are to be changed later. l The timer is a mechanism providing CPU protection. How long it runs for a particular user is a policy decision. OS Structures Slide 20

allows maximum flexibility if policy decisions are to be changed later.

21 Virtual Machines Non-virtual Machine" Virtual Machine" appearance that users have their own processor operator s console? Virtual computer/memory? OS Structures Slide 21

22 Communication Models " Communication between processes may take place using either message passing or shared memory. " Message passing l Information is exchanged through an interprocess communication facility provided by the OS l Computers have host names, processes have process names for identification purposes l Useful when smaller number of data need to be exchanged l Easier to implement than shared memory " Shared memory l Processes use map memory system calls to gain access to regions of memory owned by other processes l Allows maximum speed and convenience of communication l Problems arise in the area of protection and synchronization OS Structures Slide 22

23 Communication Models Message Passing" Shared Memory" OS Structures Slide 23

Chapter 1: Introduction. What is an Operating System?

Chapter 1: Introduction. What is an Operating System? 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