1. CS 444 Introduction to Operating Systems
Lecturer: Dr. Ronald Cheung
Office: S/3/073
Phone:

2. Course Objectives
This course will teach you details of the operating system
It will cover topics:
Processes and threads
Deadlocks
Memory management
I/O systems
File systems
Real-time operating systems (if time permits)

3. Introduction Syllabus and Lecture Notes Required Textbooks
Web:
Required Textbooks
Modern Operating Systems, 4th Ed., A. Tanenbaum

4. Introduction HW assignments Homework is an Individual Group Effort
Assignment write-ups will be on my website
HW will be done on the ulab UNIX machine by student groups (2 students to a group)
The executable will be downloaded to the SAPC VM and debugged remotely
Homework is an Individual Group Effort
You can answer questions for each other as long as you acknowledge any help that you receive from others
BUT DON’T HAVE OR LET ANYONE ELSE DO YOUR HOMEWORK FOR YOU!
Exams will definitely have programming questions
If I discover any cheating, I’ll follow school policy!

5. Getting Started
UNIX Account
Apply for a cs444 account
Edit your .cshrc file in your home to add “load module ulab” (set up environment to compile programs that can run on SAPCs)
Install VMWare Workstation 10 for PC or VMWare Fusion 8 for MAC
Download the corresponding .exe or .dmg and .txt files from /nobackup/blade71/cheungr/
Install it on your PC or MAC using the license key provided
Remote access from your home
login on “users.cs.umb.edu” using ssh2 or putty
Then ssh ulab and cd cs444
You can edit your files and compile a program for the SAPC
Download the executable to the SAPC VM and debug

6. Getting Started Putty (Officially Recommended by Systems Staff)
Download, UnZIP and Execute Installer as directed
Use Putty configured for SSH2 instead of TELNET
Use PSCP or PSFTP for secure ftp

7. Getting Started
Assume students know C programming, make, and tools such as mtip, Tutor, gdb from ulab
Useful links on ulab:
Professor Wilson’s CS 341 lectures:

8. Components of a Computer System
Physical Devices
Microarchitecture
Machine Language
Operating System
Compilers
Editors
Command
Interpreter
Spread sheet
Web Browser
Games
Hardware
System programs
Application programs
Operating system runs in kernel (supervisory) mode
Protected from user tempering by hardware
Other software runs in user mode
users are free to modify if he/she so chooses
Boundary between Operating Systems and User mode programs is blurred

9. What is an Operating System?
Programming at machine language level primitive and awkward. Operating Systems provide:
a clean abstract set of services to access hardware resources that is easier to program
Management of these resources

10. A Bottom-up View OS manages all pieces of a complex system
Provides an orderly and controlled allocation and access of hardware resources
Arbitrates which application has access to what resources at what time

11. Timeline of OS Milestones
Apple
DOS 3.1
Windows NT
Windows 98
OS/2
Apple
MAC
Windows
Vista
PC-DOS
Windows
3.0
MAC OS
MAC
OS X
UNIX
CP/M
1970
1980
1990
2000
2010
Windows 95
NeXT
Step
Windows XP
Windows 7
BSD
UNIX
GNU
LINUX
Windows
ME, 2000
Windows
1.01; Atari ST
source:

12. Categories of Operating Systems
Server OS (UNIX, Windows Server, Linux)
serves multiple users
PC OS (Mac OS, Windows)
serves a single user
Real-time OS (VxWorks, pSOS)
completes tasks within a given time budget
Embedded OS (Blackberry OS, Apple iOS)
fits into small hand held device

13. System Calls What is a System Call?
Interface between user programs and the operating system
User program transfers control to the operating system using a trap instruction. Once it completes the work, it returns the program to user space
System calls vary from one operating system to another

14. Types of System Calls
UNIX/LINUX- POSIX (International standard )
Process Management
File management
Directory Management
Miscellaneous
Windows Win32 API
Compatible among Windows versions
Many are library calls (user mode to user mode)
About
100 calls
Several
1000 calls

15. User Memory Layout Important powers of 2: 1G=230, 1M=220, 1K=210
reserved
code
data
stack 0x 0x
0xFFFFFFFF
0x7FFFFFFF
Solaris UNIX
Win 32
C lib Dll
Important powers of 2:
1G=230, 1M=220, 1K=210
0xFFFFFFFF = = 4G-1

16. Dynamic Link Library(DLL)
Also known as dynamic library
code can be called by a program that is not stored in the program’s executable file
brought to memory at runtime via dynamic linkage to user’s program
calls to library are direct since it is in user memory

17. Example of UNIX System Calls
See debugging session captured in syscalls.html
C program runs on a Sun Sparc machine with the Solaris OS