CMPT 300 Day: Operating System Instructor: Senqiang Zhou TA: Rong Ge {szhoua, rge}@cs.sfu.ca.
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CMPT 300 Day: Operating System Instructor: Senqiang Zhou TA: Rong Ge {szhoua, rge}@cs.sfu.ca
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Transcript of CMPT 300 Day: Operating System Instructor: Senqiang Zhou TA: Rong Ge {szhoua, rge}@cs.sfu.ca.
CMPT 300 Day: Operating System
Instructor: Senqiang Zhou TA: Rong Ge {szhoua, rge}@cs.sfu.ca
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What Is This Course About?
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Office Hours & Places Instructor:
Time: Mon. 14:30-15:30 Wed 11:00-12:00 Place: ASB 9911
TA: Time: Tue. 10:00-12:00 Fri. 14:00-15:00 Place: MTF109 North - CSIL Linux Study Area
E-MAIL List: [email protected] ACS SFU account desk at Strand Hall
Course web-page: http://www.cs.sfu.ca/CC/300/szhoua/
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Grading
Four assignments count for 20%. One term project counts for 15%. One 1-hour mid-term exam counts for
20%. Covers Ch 1 to Ch 3 .
One 3-hour final exam counts for 45%. Covers Ch1 to Ch 6.
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Pre-requisites
C/C++: Necessary for term project Necessary to understand the codes in
textbook Basic hardware knowledge:
CPU, memory, bus, hard disk, I/O devices
Basic data structures: Queue, stack, etc.
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Chapter 1 Introduction
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Outline
Definitions of operating system History of operating systems Categories of operating systems Computer hardware review Operating system concepts System calls
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Why Do We Need OS?
Many resources Hardware: processors, memory, disks,
printers, keyboard, monitors, network interfaces, …
Software: compilers, office tools, browsers, games, …
Many tasks Programming, surfing web, handling emails,
solving equations, playing music, … Many users
Share the resources: fairness Vs. Efficiency
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A Computer Without OS
Consider a daily task: read data from diskette Basic commands: 13 parameters
Disk address, #blocks to read, #blocks per track….
Controller chips 23 status and error field
Do you want to program the hardware directly?
A simpler interface is needed!
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The Benefits of OS
Hide the tedious details They are out of the user’s interest E.g., to access data, only need to specify the
file name. Provide a variety of services: system
calls A set of procedures an be called by programs using special
instructions. A simple interface
Present key features to programmer Meet requirements from many programs
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OS As A Virtual Machine
Virtual machine/extended machine Hide the underlying hardware Access hardware through a set of
system calls Trade-off
Higher efficiency in program development and system management
More important with complex software Less efficiency in program execution
Less important with faster machine
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OS As A Resource Manager Multiplexing (sharing) resources
In time Users/programs take turns using resources CPU, printers, etc.
In space Users/programs get parts of resources Main memory, disk, etc.
Protecting resources E.g., user’s memory space
Issues about a good manager Fairness, efficiency, safety, …
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What Is An Operating System?
Provide user programs with a simpler interface
Manage resources
Banking system
Airline reservation
Web browserUser programs
Compilers EditorsCommand interpreter System
programsOperating system
Machine language
Hardware
Micro-architecture
Physical devices
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Outline
What is an operating system? History of operating systems Categories of operating systems Computer hardware review Operating system concepts System calls
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History of Operating Systems
OS and architecture of computers Computer evolves so does OS To provide better service OS has
impact on computer design Keep evolving through years (1944-)
Four generations so far during 60 years Speed, volume, storage, interface… Most important: price keeps dropping How many generations for car industry?
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The First Generation Computer Vacuum tubes and plug-boards
1944-1955 Huge volumes, slow speed, low stability, expensive!
Applications: Straightforward numerical calculations Absolutely no game!
Scenario Single group of people designed, built, programmed,
operated and maintained a machine All in absolute machine language: no assembly
language No operating system
People did all the tasks.
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The Second Generation OS
Transistors and batch systems 1955-1965
Applications Scientific and engineering calculation Programming Language: FORTRAN
IBM 1401 IBM 7094 IBM 1401
Cards from programmers
Read batch of jobs onto tape
Input tape
Do computing
Output tape
Print out
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Ancestor of Today’s OS
Batch system Read a job from tape run the job
write output onto a output tape Load next job
A typical input job: series of commands $JOB$FORTRAN$LOAD$RUN
Examples: FMS, IBSYS
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The Third Generation OS
Features: ICs and multiprogramming 1965-1980
Applications Numerical calculations in science &
engineering Word-oriented, large-scale scientific
computers Massive commercial data processing
Character-oriented, commercial computers
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Key Advances in 3rd Gen OS
Multiprogramming Run job 2 while job 1 waiting for I/O Keep CPU busy
Spooling Read jobs from cards to disk asap Load new jobs from disk whenever old job
done Time sharing
CPU is allocated in turn Different from multiprogramming
Job 3
Job 2
Job 1
OS
Memory partitions
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Milestones
IBM OS/360 M.I.T. CTSS M.I.T. MULTICS Ken Thompson UNIX
AT&T UNIX System V UC Berkeley UNIX BSD IEEE POSIX Andrew S. Tanenbaum MINIX Linus Torvalds Linux
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The Fourth Generation OS Personal computers
1980-now VLSI circuits Cheap: an individual has her own computer
Milestones Kildall CP/M for Intel 8080, Z80 MS-DOS/BASIC for IBM PC Engelbart GUI MS Windows, Windows NT UNIX X Windows Network & distributed operating systems
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Outline
What is an operating system? History of operating systems Categories of operating systems Computer hardware review Operating system concepts System calls
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Categories of OS
Mainframe operating systems Server operating systems Multiprocessor operating systems Personal computer operating
systems Real-time operating systems Embedded operating systems Smart card operating systems
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Mainframe Operating Systems
Characters of mainframe computers Strong I/O capability, e.g., 1000 disks,
TB space High-end servers: web server, B2B
server Features of OS
Batch (background) Transaction processing (interactive) Timesharing
Example: IBM OS/390
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Server Operating Systems
Hardware platforms Very large personal computers or
workstations Services
Printing File accessing Web
Examples UNIX, Windows 2000, Linux
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Multiprocessor Operating Systems
Multiple CPUs within a single system Parallel computers:
Local memory, connected via WAN, loosely coupled
Multi-computers: Local memory, connected via LAN, tightly coupled
Multiprocessors: share memory, connected via BUS
Features of OS Variations of the server operating systems
Special features for communication and connectivity between CPUs
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Personal Computer OS
User friendly interface Easy to manipulate Abundant application software: word
processing, spreadsheets, internet access, game…
Examples Windows 98, Windows 2000 Macintosh operating system Linux
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Outline
What is an operating system? History of operating systems Categories of operating systems Computer hardware review Operating system concepts System calls
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Components of A Computer
System bus: connect all components
Bus
CPU MemoryVideo
controllerKeyboard controller
Floppy disk
controller
Hard disk controller
Monitor Keyboard
Floppy disk
driver
Hard disk
driver
I/O Devices
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CPU (Processor)
Basic model Fetching instruction decoding executing Different CPUs have different instruction sets.
Registers Program counter: pointer to next instruction PSW: program status word
Condition code bit, the mode (kernel or user), etc. Stack pointer: point to the top of current stack General registers: hold temporary results
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Working Modes
Two modes in CPU Kernel mode: full capability User mode: I/O, memory protection
instructions are disallowed. System calls: get OS service for user
program, switch to kernel mode by TRAP instruction.
User Program
OS User ProgramSystem
CallService Done
User mode
Kernel mode
User mode
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Memory Hierarchy
Typical access time
Typical capacity
1 nsecRegiste
r<1 KB
2 nsec Cache 1 MB
10 nsec Main memory 64MB-1G
10 msec Magnetic disk 5-100 GB
100 sec Magnetic tape 20-100 GB
Reason: Trade off between speed and Cost
RAM
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Memory Management
Hold multiple programs in main memory Improve CPU utilization. Why?
Problems Protection
Program A is not allowed to fetch data within program B
Protect kernel from users’ programs Relocation
Each program starts from logical address 0 How to load and allocate them into main
memory?
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Base/Limit Registers
Base register Point to the start of a program Its content is added to every
program address Limit register
Record the size of program + data Limit of addresses
Virtual address physical address Base = 4096, limit = 6114 Virtual addr = 2000 physical addr
= 2000+4096=6096 < limit, legal! MMU: memory management unit
User program and data
User program and data
Operating system
0
Base
Limit
0xFFFFFFF
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Split Program and Data Why: multiple users
may run a same program
How: base/limit registers for program and data, respectively
Overhead of switching: context switch
User-2 data
User-1 data
User program
Operating system
Base-1
Limit-1
Registers when
running program 1
Base-2
Limit-2
Base-2
Limit-2
Registers when
running program 2
Base-1
Limit-1
