1. Figure 1.1 Interaction between applications and the operating system.
1.10 Application Bases
Figure 1.1 Interaction between applications and the operating system.

2. 1.12.1 Core Operating System Components
User interaction with operating system
Often, through special application called a shell
Kernel
Software that contains core components of operating system
Typical operating system components include:
Processor scheduler
Memory manager
I/O manager
Interprocess communication (IPC) manager
File system manager

3. 1.12.2 Operating System Goals
Users expect certain properties of operating systems
Efficiency
Robustness
Scalability
Extensibility
Portability
Security
Protection
Interactivity
Usability

4. 1.13.1 Monolithic Architecture
Figure 1.3 Monolithic operating system kernel architecture.

5. Figure 1.4 Layers of the THE operating system.
Layered Architecture
Figure 1.4 Layers of the THE operating system.

6. 1.13.3 Microkernel Architecture
Figure 1.5 Microkernel operating system architecture.

7. 1.13.4 Networked and Distributed Operating Systems
Figure 1.6 Client/server networked operating system model.

8. What is the difference between a purely layered architecture and a microkernel architecture?
Which of the OS goals correspond to the following characteristics?
Users can’t access services or information w/o authorization
OS run on a variety of hardware configurations
System performance increases steadily when additional MEM and processors are added.
The OS supports devices that were not available when it was designed.
Hardware failure does not necessarily cause the system to fail.

9. Chapter 2 – Hardware and Software Concepts
Outline Introduction 2.2 Evolution of Hardware Devices 2.3 Hardware Components Mainboards Processors Clocks Memory Hierarchy Main Memory Secondary Storage Buses Direct Memory Access (DMA) Peripheral Devices 2.4 Hardware Support for Operating Systems Processor Timers and Clocks

10. Chapter 2 – Hardware and Software Concepts
Outline (continued) Bootstrapping Plug and Play 2.5 Caching and Buffering 2.6 Software overview 2.7 Application Programming Interfaces (APIs) 2.8 Compiling, Linking and Loading 2.9 Firmware 2.10 Middleware

11. Objectives After reading this chapter, you should understand:
hardware components that must be managed by an operating system.
how hardware has evolved to support operating system functions.
how to optimize performance of various hardware devices.
the notion of an application programming interface (API).
the process of compilation, linking and loading.

12. T/F?
1. OS is a resource manager, it can manage the following resources:
processors
memory
secondary storage (such as hard disks)
other I/O devices
processes
threads
files
databases
2. Most operating systems are independent from the hardware configurations, because they use device drivers to perform device-specific I/O operations.
3. Registers are high-speed memory located on processors. Data need to be loaded to registers before processors can operate on them.
4. What is a port ? What is an I/O channel?

13. 2.3.8 Direct Memory Access (DMA)
DMA improves data transfer between memory and I/O devices
Devices and controllers transfer data to and from main memory directly
Processor is free to execute software instructions
DMA channel uses an I/O controller to manage data transfer
Notifies processor when I/O operation is complete
Improves performance in systems that perform large numbers of I/O operations (e.g., mainframes and servers)

14. 2.3.8 Direct Memory Access (DMA)
Figure 2.4 Direct memory access (DMA).

15. 2.4 Hardware Support for Operating Systems
What can a processor do to enforce protection?
Execution modes
Bound registers
Interrupts and exceptions

16. 2.4.1 Processor
A processor implements operating system protection mechanisms
Prevents processes from accessing privileged instructions or memory
Computer systems generally have several different execution modes:
User mode (user state or problem state)
User may execute only a subset of instructions
Kernel mode (supervisor state)
Processor may access privileged instructions and resources on behalf of processes

17. 2.4.1 Processor Memory protection and management
Prevents processes from accessing memory that has not been assigned to them
Implemented using processor registers modified only by privileged instructions
Interrupts and Exceptions
Most devices send a signal called an interrupt to the processor when an event occurs
Exceptions are interrupts generated in response to errors
The OS can respond to an interrupt by notifying processes that are waiting on such events

18. 2.7 Application Programming Interfaces (APIs)
Figure 2.7 Application programming interface (API).