Operating System Design And Implementation & System Structure
Operating System Design And Implementation
Design Goals: design of a system affected by choice of hardware and the type of system: batch, time sharing, single user , multiple user, distributed, real time or general purpose.
System should be convenient to use , easy to understand(learn), reliable (safe), fast.
Mechanism and Policies: Separation of policy from mechanism. Mechanisms determine how to do something; policies determine what will be done.
Implementation:
Emulators: are programs that duplicate the functionality of one system on another.
System should be convenient to use , easy to understand(learn), reliable (safe), fast.
Mechanism and Policies: Separation of policy from mechanism. Mechanisms determine how to do something; policies determine what will be done.
Implementation:
Emulators: are programs that duplicate the functionality of one system on another.
System Structure
1. Simple Structure
2.Layered Approach
OS is broken down into number of layers in which the initial layer is the hardware whereas the last layer is user interface.
The difficulty faced in this approach is of appropriately defining the various layers because a layer can use the layers beneath it
3. Micro kernels
MACH was an operating system that modularized kernel using micro-kernel.
This method structures the operating system by removing all non-essential component from the kernel and implementing them as system and user level programs.
OS is broken down into number of layers in which the initial layer is the hardware whereas the last layer is user interface.
The difficulty faced in this approach is of appropriately defining the various layers because a layer can use the layers beneath it
3. Micro kernels
MACH was an operating system that modularized kernel using micro-kernel.
This method structures the operating system by removing all non-essential component from the kernel and implementing them as system and user level programs.
4. Modules
In this approach kernel has a set of core components and links in additional services via modules, either at boot time or during run time.
In this approach kernel has a set of core components and links in additional services via modules, either at boot time or during run time.