Download TCSS 422: Operating Systems - Course Syllabus and Introduction and more Exams Operating Systems in PDF only on Docsity!
Institute of Technology
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma
INTRODUCTION
Wes J. Lloyd
Institute of Technology
University of Washington - Tacoma
TCSS 422: OPERATING SYSTEMS
Syllabus, Course Introduction
C Review
Demographics Survey
Chapter 4: Operating Systems – Three Easy Pieces
Introduce operating systems
Management of resources
Concepts of virtualization/abstraction
CPU, Memory, I/O
Operating system design goals
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
OBJECTIVES
Syllabus
Grading
Schedule
Assignments
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
TCSS422 – SPRING 2018
COMPUTER OPERATING SYSTEMS
TCSS 422 – Spring 2018
Special features!
Going green…
20% reduction of carbon footprint
16 in person class meetings
Online lectures: Monday April 16, Wednesday April 18 No class: Monday April 9, Monday May 28
Saves commuting time
Less fuel expenses Easier to achieve perfect attendance
Final exam Monday June 4th
71 days from now…
TCSS 422
SPRING
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
Assignments
Assignment 0: Linux /scripting
Assignments 1 – 3 (4): roughly every two weeks
Quizzes
~ 6-8 quizzes
Drop lowest two
Variety of formats: in class, online, reading, tutorial / activity
Exams: Midterm and Final
Two pages of notes, calculator
Final exam is comprehensive, with emphasis on new material
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
TCS422 COURSE WORK
Programs - please start early: March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
TCSS 422: PROGRAM DUE DATES
From Virginia Tech Department of Computer Science - 2011 Better than 50% chance of A/B Less than 50% chance of A/B
Institute of Technology
Programs - please start early Work as if deadline is several days earlier Allows for a “buffer” for running into unexpected problems
Underestimation of the task at hand
Allows time to seek C help from SCI 106/108 lab
mentors
If less familiar with C/pointers (TCSS 333),
BUDGET MORE TIME
This quarter: 5% bonus for submitting on the original posted due date
Excludes any class-wide extensions
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
TCSS 422: PROGRAM DUE DATES
Ubuntu 16.
Open source version of Debian-package based Linux
Package management: “apt get” repositories
See: https://packages.ubuntu.com/
Ubuntu Advantages
Enterprise Linux Distribution
Free, widely used by developers
Long term releases (LTS) every 2 years, good for servers
6 month feature releases, good for sharing new features
with the community
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
UBUNTU 16.04 – VIRTUAL MACHINE
Ubuntu 16.
Search online for YouTube videos, tutorials
Search how to install the “Guest Additions”
Provides file system sharing, clipboard integration, mouse
tricks
Windows 10
https://www.youtube.com/watch?v=DPIPC25xzUM
Mac OS X
https://www.youtube.com/watch?v=sNixOS6mHlU
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
UBUNTU 16.04 – VIRTUAL MACHINE
INSTALLATION
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
C PROGRAMING IN TCSS 422
Many OSes are coded primarily in C and Assembly Language
Computerworld, 2017 Tech Forecast Survey
https://www.tacoma.uw.edu/institute-technology/student-
support-workshops-mentors
Institute of Technology Mentors
Located in Science 106 / 108 Labs
Monday – Thursday: ~10 am – 7 pm
Friday: ~ 1 2-5pm
Spring quarter hours to be posted
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
C MENTORING
Office hours: to be announced, and by appointment
End of class: good for quick questions, assignment Q&A
It will be difficult to tutor all 50 students individually on C
Take ownership of your educational outcome
Time spent in TCSS 422 is just ~0.4% of an IT career
Make the most of this limited time
Maximize your educational investment
*** Ask questions in class ***
Also questions after class, email, Canvas discussion boards
Seek help using UWT resources, the internet, YouTube videos
(video.google.com) and online tutorials
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
INSTRUCTOR HELP
Institute of Technology
Responsible for: Making it easy to run programs Allowing programs to share memory Enabling programs to interact with devices March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
OPERATING SYSTEMS
OS is in charge of making sure the system operates correctly and efficiently. The OS is a resource manager Manages CPU, disk, network I/O Enables many programs to Share the CPU Share the underlying physical memory (RAM) Share physical devices
Disks
Network Devices
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
RESOURCE MANAGEMENT
Operating systems present physical resources as virtual representations to the programs sharing them
Physical resources: CPU, disk, memory, …
The virtual form is “abstract” The OS presents an illusion that each user program runs in isolation on its own hardware This virtual form is general, powerful, and easy-to-use March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZATION
What form of abstraction does the OS provide? CPU
Process and/or thread
Memory
Address space
large array of bytes
All programs see the same “size” of RAM
Disk
Files
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
ABSTRACTIONS
Allow applications to reuse common facilities Make different devices look the same Easier to write common code to use devices Linux/Unix Block Devices Provide higher level abstractions More useful functionality March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
WHY ABSTRACTION?
What level of abstraction? How much of the underlying hardware should be exposed? What if too much? What if too little? What are the correct abstractions? Security concerns March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
ABSTRACTION CHALLENGES
Institute of Technology
Each running program gets its own “virtual” representation of
the CPU
Many programs seem to run at once
Linux: “top” command shows
process list
Windows: task manager
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZING THE CPU
Simple Looping C Program
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZING THE CPU - 2
12 #include#include <stdio.h><stdlib.h> 34 #include#include <sys/time.h><assert.h> 56 #include "common.h" 78 intmain(int argc, char *argv[]) 910 { if (argc != 2 ) { 1112 fprintf(stderr,exit( 1 ); "usage: cpu \n"); 1314 }char *str = argv[ 1 ]; 1516 while ( 1 )Spin( { 1 ); // Repeatedly checks the time and 17 returnsprintf("%s\n", str);^ once^ it^ has run for a second 1819 }return 0 ; 20 }
Runs forever, must Ctrl-C to halt…
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZING THE CPU - 3
prompt> gcc prompt> ./cpu "A" -o cpu cpu.c -Wall A A A ˆC prompt> March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZATION THE CPU - 4
prompt> ./cpu A [1] 7353 & ; ./cpu B & ; ./cpu C & ; ./cpu D & [2] 7354 [3] 7355 [4] 7356 A B D C A B D C A C B D ... Even though we have only one processor, all four of programs seem to be running at the same time!
Computer memory is treated as a large array of bytes
Programs store all data in this large array
Read memory (load)
Specify an address to read data from
Write memory (store)
Specify data to write to an address
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZING MEMORY
Program to read/write memory:
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
VIRTUALIZING MEMORY - 2
12 #include#include <unistd.h><stdio.h> 34 #include#include <stdlib.h>"common.h" (^56) int 78 main({ int argc, char *argv[]) 9 int *p = malloc(sizeof(int)); memory // a1: allocate some 1011 assert(pprintf("(%d) != NULL address); of p: %08x\n", 12 getpid(), (unsigned) address p); (^) of the// a2: memmoryprint out the 1314 p =while 0 ;( (^1) )// a3: { put zero into the first slot of the memory 1516 Spin(p = *p 1 ); + 1 ; (^1718) } printf("(%d) p: %d\n", getpid(), *p); // a (^1920) } return 0 ;
Institute of Technology
Program creates two threads
Check documentation: “man pthread_create”
worker() method counts from 0 to argv[1] (loop)
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
CONCURRENCY - 3
1617 intmain(int argc, char *argv[]) 1819 { if (argc != 2 ) { 2021 fprintf(stderr,exit( 1 ); "usage: threads \n"); 2223 }loops = atoi(argv[ 1 ]); 2425 pthread_t p1, p2;printf("Initial value : %d\n", counter); (^2627) Pthread_create(&p1, NULL, worker, NULL); 2829 Pthread_create(&p2,Pthread_join(p1, NULL NULL);, worker, NULL); 3031 Pthread_join(p2,printf("Final value : %d\n", NULL); counter); (^3233) } return 0 ; March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
Linux
“man”
page
example
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
CONCURRENCY - 4
Command line parameter argv[1] provides loop length
Defines number of times the shared counter is incremented
Loops: 1000
Loops 100000
prompt> prompt> gcc./thread 1000 -o thread thread.c -Wall -pthread Initial Final value value : : 2000 0 prompt> Initial ./thread 100000value : 0 Final value prompt> ./thread 100000 : 143012 // huh?? Initial Final value value : : 137298 (^0) // what the??
When loop value is large why do we not achieve 200000?
C code is translated to (3) assembly code operations
1. Load counter variable into register
2. Increment it
3. Store the register value back in memory
These instructions happen concurrently and VERY FAST
(P1 || P2) write incremented register values back to memory,
While (P1 || P2) read same memory
Memory access here is unsynchronized (no n-atomic)
Some of the increments are lost
March 26, 2018 TCSS422: Operating Systems [Spring 2018] Institute of Technology, University of Washington - Tacoma L1.
CONCURRENCY - 5
QUESTIONS
