Operating Systems. Design and Implementation. Andrew S. Tanenbaum Melanie Rieback Arno Bakker. Vrije Universiteit Amsterdam

Operating Systems Design and Implementation Andrew S. Tanenbaum Melanie Rieback Arno Bakker Vrije Universiteit Amsterdam Operating Systems - Winter 2012

Outline Introduction What is an OS? Concepts Processes and Threads Memory Management File Systems Vrije Universiteit Amsterdam Slide 4

Chap 1 - Overview What is an Operating System? Concepts System Calls Structure Vrije Universiteit Amsterdam Slide 4

What is an OS? Vrije Universiteit Amsterdam Slide 13

2 Views on OSes OS as a Virtual Machine Extending the HW functionality Hides the messy details of programming the HW OS as a Resource Manager Protects against simultaneous usage of resources Fair sharing of resources (scheduling) Resource accounting Vrije Universiteit Amsterdam Slide 15

How to View an OS Operating Systems 2011 Program OS System calls Vrije Universiteit Amsterdam Slide 16

Concept: Processes Operating Systems 2011 Vrije Universiteit Amsterdam Slide 17

Multiple Processes Operating Systems 2011 init shell Vrije Universiteit Amsterdam some_ program Slide 18

System Calls Operating Systems 2011 System Calls are the interface the Operating System offers to applications. Problem: Mechanics of issuing a system call are highly machine dependent Solution: Provide a library to allow system calls from C programs: libc Library functions System Calls Instruction Set Architecture Applications / Processes Libraries Operating System Hardware Bash libc Linux kernel x86_64 Vrije Universiteit Amsterdam Slide 27

System Calls: Process Management (1/2) Vrije Universiteit Amsterdam Slide 28

System Calls: Process Management (2/2) Vrije Universiteit Amsterdam Slide 29

System Calls: Signals Operating Systems 2011 Vrije Universiteit Amsterdam Slide 30

Concept: Mounting (1/2) Operating Systems 2011 Vrije Universiteit Amsterdam Slide 23

File System Mounting (2/2) Operating Systems 2011 Vrije Universiteit Amsterdam Slide 24

Special Files (1/2) Storage devices are mapped into the file tree via mounting. Idea: do this for all devices. Mechanism: Special files in /dev Two types: Operating Systems 2011 Vrije Universiteit Amsterdam Slide 25

Special Files (2/2) Operating Systems 2011 Vrije Universiteit Amsterdam Slide 26

System Calls: Files Operating Systems 2011 Vrije Universiteit Amsterdam Slide 31

System Calls: Directories Operating Systems 2011 Vrije Universiteit Amsterdam Slide 32

System Calls: Implementation Operating Systems 2011 Vrije Universiteit Amsterdam Slide 35

OS Structure: UNIX Operating Systems 2011 Vrije Universiteit Amsterdam Slide 37

OS Structure: Linux Operating Systems 2011 Vrije Universiteit Amsterdam Slide 38

Operating Systems Chapter 2 - Processes Vrije Universiteit Amsterdam Operating Systems - Winter 2012

Chap 2 - Overview Scheduling Processes Threads Vrije Universiteit Amsterdam Slide 1

Recall: Process Vrije Universiteit Amsterdam Slide 2

One CPU, Many Processes Processes share the CPU(s) A scheduler determines which process to run next Keeps track of the process state Following some scheduling policy (random robin, shortest job first, etc). Vrije Universiteit Amsterdam Slide 3

Process States Vrije Universiteit Amsterdam Slide 5

Context Switching Operating Systems 2011 Vrije Universiteit Amsterdam Slide 39

Process Implementation Operating Systems 2011 Process Table: ps -ef Vrije Universiteit Amsterdam Slide 7

Threads Operating Systems 2011 Vrije Universiteit Amsterdam Slide 10

Threads: Minimal Support Operating Systems 2011 Vrije Universiteit Amsterdam Slide 11

Threads Some Problems Operating Systems 2011 Vrije Universiteit Amsterdam Slide 12

Mutual Exclusion Operating Systems 2011 Vrije Universiteit Amsterdam Slide 15

Operating Systems Chapter 4 Memory Management Vrije Universiteit Amsterdam Operating Systems - Winter 2012

Chap 4 - Overview Memory Management Paged Memory Virtual Memory Segmentation Vrije Universiteit Amsterdam Slide 1

Memory Management Simple Vrije Universiteit Amsterdam Slide 2

Memory Management - Complex Multiple processes in the same memory Vrije Universiteit Amsterdam Slide 10

Paged Memory Systems (1/2) Vrije Universiteit Amsterdam Slide 15

Paged Memory Systems (2/2) Vrije Universiteit Amsterdam Slide 17

Virtual Memory Idea: Not all virtual pages have to be in physical memory Instead stored on disk -> cheap storage In swap partition Much more memory available Works if not all pages are used at the same time Vrije Universiteit Amsterdam Slide 24

Segmentation N Stack 0 Data Code N 0 Code Data Stack Segments can grow independently Hardware helps to map segments to virtual memory Hardware helps to protect: read-only, no-execute Vrije Universiteit Amsterdam Slide 35

Operating Systems Chapter 5 File Systems Vrije Universiteit Amsterdam Operating Systems - Winter 2012

Chap 5 - Overview Files Directories File system implementation UNIX/MINIX filesystem Vrije Universiteit Amsterdam Slide 1

Directories i-node Vrije Universiteit Amsterdam Slide 5

File Attributes Vrije Universiteit Amsterdam Slide 4

Directories Pathnames Vrije Universiteit Amsterdam Slide 6

File System Design Vrije Universiteit Amsterdam Slide 7

File Storage: Disk Layout Vrije Universiteit Amsterdam Slide 8

File Storage Inodes Vrije Universiteit Amsterdam Slide 11

File Storage UNIX Vrije Universiteit Amsterdam Slide 13

File Storage Name Resolution Vrije Universiteit Amsterdam Slide 14

Disk Space Management (1/2) Vrije Universiteit Amsterdam Slide 15

File System Consistency Vrije Universiteit Amsterdam Slide 18

Buffer Cache Vrije Universiteit Amsterdam Slide 20

Log-Structured File Systems Vrije Universiteit Amsterdam Slide 21

MINIX Filesystem Vrije Universiteit Amsterdam Slide 31

MINIX Superblock Vrije Universiteit Amsterdam Slide 32