Chapter 2 operating system logical structure
2.1 Logical Structure of the operating system
2.2 CPU states
2.3 interrupt mechanism
2.1 Logical Structure of the operating system
Logical structure: the design and implementation of ideas OS
Category:
1. Overall structure
2. The hierarchical structure
3. microkernel architecture (Client / Server structure)
- Unitary structure
to construct the basic unit module
1. modular design, coding and debugging independent
2. Module calls consisting
3. The multi-module communication done in the form of a global variable
Shortcoming
messaging random, difficult to maintain and update.
- Hierarchy
layering principle;
1. related hardware - the bottom
2. The external characteristic - an outermost layer
3. The intermediate layer - call or message delivery order sequence
4. The common service - the lower layer
5. The active functions - - lower level
The advantages of hierarchy;
1. The clear structure and avoid the cycle call.
2. The overall problem localized, easy to guarantee the correctness of the system.
3. To help maintain the operating system, expansion transplant.
-
Microkernel
operating system microkernel + = extranuclear server -
Microkernel: small enough to provide the most basic core OS functions and services
-
Nuclear outside the server:
the completion of most of the service functions of the OS, wait for the application request.
Or by a number of server processes together form
such as: process / thread server, virtual memory server, device management servers.
Run in user mode to process the form.