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?
If data is not very much, we can use message passing. Because no conflicts need to be avoided. It’s easier to control process than use shared-memory.
Shared-memory requires that they agree to remove the restriction of preventing one process from accessing another process’ memory. But it probably have problems like race condition and execution errors. If using message passing, when the link buffer is full, the message which sender passed can’t stay in the link, so the sender have to wait until the receive get the message.
2. What is “system calls?” Please specify the functions and the purposes of a system call in a computer system.
A system call is how a program requests a service from an operating system's kernel. This may include hardware-related services (for example, accessing a hard disk drive), creation and execution of new processes, and communication with integral kernel services such as process scheduling. System calls provide an essential interface between a process and the operating system.
3. Please specify different ways for using the hardware configuration during the system generation (SYSGEN). What are the major differences between these different ways?
Modify a copy of the source code is bigger than create tables and modules.