2015/11/06 2015/11/06 OS作業

2015/11/06 OS作業
Homework for Chapter 2:
1. Which situation is suitable to use message passing instead of shared-memory model for communication between processes? What are the pros and cons of using these two models?
In addition, when a small number of information exchange, most of the time is the use of shared-memory model.
The advantage of shared-memory model is to achieve maximum communication speed and convenience, both the disadvantage is that there is still a lot of protection and synchronization problems
2. What is “system calls?” Please specify the functions and the purposes of a system call in a computer system.
System call provide the interface between a running program and the operating system.
System call is available to the operating system used by the application function call. Usually the system call will cause the system transferred to the program executed in kernel mode. System call is to allow the operating system to make smooth.
3. Please specify different ways for using the hardware configuration during the system generation (SYSGEN). What are the major differences between these different ways?
Used to modify a copy of the source code of the OS and have it re-compiled.
Used to create tables and modules from a precompiled library. The needed modules are linked together to form the generated OS.
Construct a system that is completely table driven. All the code is always part of the system, and selection occurs at execution time.
The size and generality of the generated system and the ease of modification sa the hardware configuration changes.