Question

1. Draw or describe the memory space for a process.
2. What happens in the New state?
3. List three general categories of information in a process control block.
4. Why are two modes (user and kernel) needed?

Please show all work and thought process

Answer 1

a. The process in the memory space is given as follows:

Process memory is divided into four sections as in fig below:

• The text section comprises the compiled program code, read in from non-volatile storage when the program is launched.
• The data section stores global and static variables, allocated and initialized prior to executing main.
• The heap is used for dynamic memory allocation, and is managed via calls to new, delete, malloc, free, etc.
• The stack is used for local variables. Space on the stack is reserved for local variables when they are declared ( at function entrance or elsewhere, depending on the language ), and the space is freed up when the variables go out of scope. Note that the stack is also used for function return values, and the exact mechanisms of stack management may be language specific.

b. The new state in the process is state where the process is created.

• New - The process is in the stage of being created.

c. The three types of information in process control block is:

• Process identification: Process identification data include a unique identifier for the process
• Process state: Process state data define the status of a process when it is suspended, allowing the OS to restart it later.
• Process control: The process control information is used by the OS to manage the process itself.

d. There are two modes user and kernel:

User Mode
The system is in user mode when the operating system is running a user application such as handling a text editor. The transition from user mode to kernel mode occurs when the application requests the help of operating system or an interrupt or a system call occurs.
​

Kernel Mode:The system starts in kernel mode when it boots and after the operating system is loaded, it executes applications in user mode. There are some privileged instructions that can only be executed in kernel mode.

So, the user mode is for simple applications while the kernel mode is for privileged applications.

-----------------------------------------------------------Please Upvote--------------------------------------------------------------------