Operating System Structures

1. Pass Control

2. Many systems traditional

2.1. o Device drivers o File systems o Virtual memory manager o Windowing system o Security services

3. System Calls

3.1. available as assemble-language instrutions

3.2. Languages defined to replace assembly language for systems programming

3.3. 3 methods to pass parameter

4. Type of System Calls

4.1. Device Management

4.2. Information Maintenance

4.3. Communications

4.4. Protections

4.5. File Management

5. Layered Approach

5.1. OS divided in numbers of layers

5.1.1. bottom layer (hardware)

5.1.2. highest layer (user interface)

5.2. With modularity, layers are selected such that each uses function & services

5.3. Advantages

5.3.1. Simplicity of construction and debugging

5.4. Disadvantages

5.4.1. The careful definition and interaction of the layers

5.4.2. Less efficiency

6. Microkernel

6.1. Small OS core

6.2. Contains only essential core OS functions

6.3. Benefits

6.3.1. extensibilty

6.3.2. flexibility

6.3.3. reliability

6.3.4. portability

7. Operating System Services

7.1. User Interface

7.2. Programme Execution

7.3. I/O Operation

7.4. File-System Manipulation

7.5. Communications

7.6. Error Detection

8. Additional Operating System Functions

8.1. Resource Allocation

8.2. Protection and Security

8.3. Accounting

9. OS Design

9.1. Design and Implementation of OS not “solvable”

9.2. starts by defining goals and specifications

9.3. The design of the system will be affected by the choice of hardware and the type of system

10. OS Design Goals

10.1. User goals

10.2. System goals