What is an operating system Examples of Operating
- Slides: 18
What is an operating system? Examples of Operating Systems. OSX Windows Mobile Linux Mac OS Android (open handset alliance) Unix Windows XP MS-DOS Windows 95 Windows Vista Symbian Acorn MOS
What is an operating system? • What does it do? • • Process Management Memory management I/O management Support functions Networking User interface Security
Where does it fit in? Application Program Instruction Level Operating System Instruction Set Architecture Micro architecture Implementation
Operating System Goals • • Efficiency Throughput Functionality Robustness Extensibility Portability Security Interactivity
Concepts • Architectures of Operating Systems – – – Monolithic Layered Kernel Microkernel Virtual Machines • Increasing Efficiency – Multi program – Multi User
Monolithic Architecture • Monolithic Architecture—the early operating systems – Every component is contained in the kernel, can directly communicate with other components
Monolithic Architecture Applications User Space System Calls OS Layer Computer Hardware
Monolithic Architecture • Pros – Highly efficient – by direct intercommunication between components • Cons – difficult to develop – difficult to isolate the source of bugs and other errors • particularly susceptible to damage from malicious code
Layered Architecture • Layered OS structure: – Group components that perform similar functions into layers. Each layer communicates only with neighbour layer User Space Layer 3 Layer 2 Kernel Space Layer 1 Layer 0 Computer Hardware
Layered Architecture • Pros – It provides good modularity – helps simplify the development of an OS • Cons – Less efficient – Complex design – each functionality has to be divided into parts to fit into different layers.
Kernel Based Architecture • It separates the machine-independent parts from the machine-dependent parts – Kernel is machine-dependent. It contains the basic component of OS. User Space Operating System OS Kernel Computer Hardware
Kernel Based Architecture • Pros – Better portability—Kernel encloses all the machine-dependent code • Cons – Suffers similar problem as in layered OSs
Microkernel Based Architecture • As OS expanded, the kernel became large and difficult to manage – Microkernel approach removes all nonessential components from the kernel and implementing them as system and user-level programs. • Result: A smaller kernel
Microkernel Based Architecture User Space Operating System Microkernel Computer Hardware
Microkernel Based Architecture • Pros – Enhance portability, extensibility, reliability and security • Cons – Less efficient—increased system function overhead
Virtual Machines • Can create the illusion that there are more than one separate machines. User Space Kernel VM 1 Virtual machine implementation Host Operating System Computer Hardware
Increasing Efficiency • Multiprogramming – Try to Keep the CPU busy – CPU operations take less time than I/O – When a process waits for I/O operation, OS swaps to another process. Operating System Job 1 Job 2 Job 3
Multi User – Logical extension of Multiprogramming
- Buddy system in os
- File system in operating system
- File system in operating system
- File system in operating system
- Definition of operating system
- Stand alone operating system
- Networking background
- Examples of network operating systems
- Network operating system examples
- Stand alone operating system examples
- Is earth a closed system or open system
- Respiratory system circulatory system digestive system
- Windows xp4
- Windows nt operating system
- Benefits of operating system
- Multi tasking operating system
- Block diagram of unix operating system
- Trusted os
- Tiny operating system