Modes of the user and kernel.

User Mode
User mode is composed of subsystems that transmit requests input \ output corresponding to the kernel mode driver manager by IO. The user level is composed of two subsystems - the environment (Environment) and integrated subsystem (Integral).
The subsystem environment designed to run applications written for different types of operating systems. None of the sub-systems environment has no direct access to the hardware of the computer. Access to the resources of memory occurs through the virtual memory manager that runs in kernel mode. Also, the applications start with a lower priority than kernel mode processes.
The integrated subsystem (Integral subsystem) monitors certain functions of the operating system on behalf of the environment subsystems. Consists of a security subsystem, the Workstation service and the Server service. The Security Service handles security tokens, allows or denies access to a user account, processes authorization requests and initiates the process of user logon. The Workstation service provides access to computer networks - is an API for the network redirector. The Server service allows the computer to provide network services.
Kernel mode
Windows NT kernel mode has full access to the computer's hardware and system resources. Working in a protected area of ​​memory. Controls the flow, manages memory and the interaction with the hardware. Prevents access to critical memory areas of the application and the user-mode services. To perform these operations, user-mode process is to ask the kernel mode to execute it on their behalf.
X86 architecture supports four privilege levels - from 0 to 3, but using only level 0 and 3. User mode uses a level 3, and kernel mode - 0. Kernel mode consists of executive services, which are the different modules that perform specific tasks, kernel driver, the kernel and HAL HAL
The executive subsystem.
Works with input \ output, the object manager, management of the processes and security. Unofficially divided into several sub-systems - the cache manager, configuration manager, the manager I \ O, a local procedure call, the memory manager, the security monitor
Object Manager
This is the executive subsystem that is referred to all the other modules of the executive subsystem, including system calls, when they need to access the resources Windows NT. The object manager is used to reduce duplication of objects, which may lead to errors in the system.

Date: 2015-01-29; view: 968