Operating Systems – Introduction Slide 1
Operating Systems
Rafael Ramirez (T, S)
[email protected]
55.316
Sergio Giraldo(P, S)
[email protected]
Matteo Segnorini (P, S)
[email protected]
Operating Systems – Introduction Slide 2
Operating Systems
Calendario Curso en:
Ø Web de la ESUP
Operating Systems – Introduction Slide 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
Operating Systems – Introduction Slide 4
Operating Systems
Evaluation:
Examen teoría
60%
Prácticas
30%
se ha de aprobar tanto teoria como prác/semSeminarios
10%
Prácticas = (0.6 * practicas) + (0.4 * examen de prácticas)
se ha de aprobar tanto prac-examen como prácticas
Operating Systems – Introduction Slide 5
Operating Systems – Introduction Slide 6
Operating Systems
Seminarios (4): grupos de 2-4
Prácticas (5): grupos de 2
Operating Systems – Introduction Slide 7
Operating Systems
Course Book:
A. Silberschatz, P.B. Galvin, G. Gagne. Fundamentos de sistemas operativos. McGraw Hill, 2009.
Other books:
W. Stallings. Sistemas operativos : aspectos internos y principios de diseño, Prentice Hall 2005.
L. Duran-Rodriguez. Sistemas operativos: referencia bàsica. Marcombo, 2000.
Operating Systems – Introduction Slide 8
Operating Systems
Contact:
qClase
qSeminarios/Prácticas
qq
Horas oficina: Cualquier dia (previa cita)
q
Anuncios, documentacion, …
q
Moodle +
http://www.dtic.upf.edu/~rramirez/os/
OS Introduction Slide 9
Introduction
OS Introduction Slide 10
OS Introduction Slide 11
OS Introduction Slide 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
OS Introduction Slide 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?
OS Introduction Slide 14
Types of Operating Systems?
"
OS for Distributed systems
l
Loosely coupled system
– LAN & WAN
"
Real-time OS
ltime constraints
lSoft real-time
lHard real-time
"
Hand-held OS
lLimitations
OS Structures Slide 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 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
OS Structures Slide 17
OS Structures Slide 18
Standard C Library Example
"
C program invoking printf() library call, which calls
OS Structures Slide 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
OS Structures Slide 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
OS Structures Slide 21
Virtual Machines
Non-virtual Machine" Virtual Machine"
• appearance that users have their own processor
OS Structures Slide 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
OS Structures Slide 23
