Sean Barker

Recap: The OS Abstraction

1

User-level Applications

Operating System

Hardware

virtual machine interface

physical machine interface

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OS Resource Management

2

Memory

I/O

Processor Processes, scheduling, synchronization

Allocation, protection, virtual memory

Disk management, filesystems, networking

Hardware OS Services

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Protection: User and Kernel Mode

3

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System Calls

4

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Making a System Call

5

user mode

kernel mode

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Example System Calls

6

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System Call Implementation

7

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Traps

8

0: 0x00080000

1: 0x00100000

2: 0x00100480

3: 0x00123010

Illegal address

Memory violation

Division by zero

System call

Trap Vector

...

Memory Addresses

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I/O Control & Interrupts

9

0: 0x2ff080000

1: 0x2ff100000

2: 0x2ff100480

3: 0x2ff123010

keyboard

mouse

timer

disk 1

Interrupt Vector

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Synchronous & Asynchronous I/O

10

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Hardware Timer

11

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OS Architecture: Mac OS X

12

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OS Architecture: Windows 8

13

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Monolithic Kernel Design

14

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Layered OS Design

15

User programs

Device drivers

Virtual memory

I/O channel

CPU scheduler

Hardware

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Microkernel Design

16

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Hybrid Design in Mac OS X

17

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Modular Design

18