What is meant by context of process?

The context of a process includes its address space, stack space, virtual address space, register set image (e.g. Program Counter (PC), Stack Pointer (SP), Instruction Register (IR), Program Status Word (PSW) and other general processor registers), updating profiling or accounting information, making a snapshot image …

Where is the process context kept?

This is usually stored in a data structure called a process control block (PCB) or switchframe. The PCB might be stored on a per-process stack in kernel memory (as opposed to the user-mode call stack), or there may be some specific operating system-defined data structure for this information.

What is interrupt context and process context?

When executing a interrupt handler or bottom half, the kernel is in interrupt context. Recall That process context is the mode of operation the kernel are in while it’s executing on behalf of a process– For example, executing a system call or running a kernel thread.

How do we save the context of a process?

Context Switching Steps

1. Save the context of the process that is currently running on the CPU.
2. Move the process control block of the above process into the relevant queue such as the ready queue, I/O queue etc.
3. Select a new process for execution.
4. Update the process control block of the selected process.

What happens on a context switch?

A context switching is a process that involves switching of the CPU from one process or task to another. In this phenomenon, the execution of the process that is present in the running state is suspended by the kernel and another process that is present in the ready state is executed by the CPU.

What are the two steps of a process execution?

Answer is “I/O Burst, CPU Burst”

Why context switching is faster in threads?

When we switch between two threads, on the other hand, it is not needed to invalidate the TLB because all threads share the same address space, and thus have the same contents in the cache. Thus context switching between two kernel threads is slightly faster than switching between two processes.

What is process context in Linux?

Process context is its current state. We need to save the context of the current running process so it can be resumed after the interrupt is handled. Process context is basically its current state (what is in its registers).

What is the function of interrupt handler?

The job of the interrupt handler is to service the device and stop it from interrupting. Once the handler returns, the CPU resumes what it was doing before the interrupt occurred. The Solaris 7 DDI/DKI provides a bus-architecture independent interface for registering and servicing interrupts.

Is context switching good?

The key reason context switching is bad is because it takes time and effort to get into focus. So every time we switch tasks, we lose energy that we wouldn’t have lost if we had just stayed on one task. Fatigue is not the only problem that arises from context switching. Productivity suffers, too.

What are the step of a process execution?

As shown in Figure 5.2, a process instance has three main stages during its lifetime: (1) process instantiation, (2) process execution and (3) process termination.

What is the main function of the command interpreter?

Explanation: The main function of command interpreter is to get and execute the next user-specified command. Command Interpreter checks for valid command and then runs that command else it will throw an error.

What’s the difference between process context and process?

A Process Context is a run-time information of a particular process at any given time. It’s all information needed for OS to restore a suspended process. It’s basically CPU registers and process stack.

What does ” process context ” mean in ESP?

Process context is its current state. We need to save the context of the current running process so it can be resumed after the interrupt is handled. Process context is basically its current state (what is in its registers). esp ss eip cs and more.

When does the kernel go into process context?

When a program executes a system call or triggers an exception, it enters Kernel-space. At this point, the kernel are said to being “executing on behalf of the process” and are in process context. When in process context, the current macro is valid.

How is the current macro related to process context?

In process context, the current macro points to the associated task. Furthermore, because a process is coupled to the kernel in process context (because the process is connected to the kernel in the same way as the process above), process context can SleeP or otherwise invoke the scheduler.