distinguish between user mode and kernel mode?
- 4 Answers
- 16170 Views
- Infosys, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / narendrasairam immadi
When a process is in user space, its system calls are being
intercepted by the tracing thread. When it's in the kernel,
it's not under system call tracing. This is the distinction
between user mode and kernel mode.
The transition from user mode to kernel mode is done by the
tracing thread. When a process executes a system call or
receives a signal, the tracing thread forces the process to
run in the kernel if necessary and continues it without
system call tracing
| Is This Answer Correct ? | 28 Yes | 5 No |
Answer / rhino
Kernel Mode (System Mode) :
in this mode executing code has complete and unrestricted
access to the underlying hardware. It can execute any CPU
instruction and reference any memory address.
Kernel mode is generally reserved for the lowest-level,
most trusted functions of the operating system. Crashes in
kernel
mode are catastrophic; they will halt the entire PC.
When the CPU is in kernel mode, it is assumed to be
executing trusted software, and thus it can execute any
instructions
and reference any memory addresses (i.e., locations in
memory).
The kernel (which is the core of the operating system and
has complete control over everything that occurs in the
system)
is trusted software, but all other programs are considered
untrusted software.
Thus, all user mode software must request use of the kernel
by means of a system call in order to perform privileged
instructions, such as process creation or input/output
operations.
User Mode :
In User mode, the executing code has no ability to directly
access hardware or reference memory. Code running in user
mode must delegate to system APIs to access hardware or
memory.
Due to the protection afforded by this sort of isolation,
crashes in user mode are always recoverable. Most of the
code
running on your computer will execute in user mode.
| Is This Answer Correct ? | 21 Yes | 2 No |
Answer / harsha
kernal mode has higher priority while user mode has lower
priority.
kernal mode has ability to read user mode but user mode has
not priority to interfare in kernal mode.
| Is This Answer Correct ? | 9 Yes | 3 No |
Answer / bhargav manne
kernal mode is access any resource regarding the hardware
i.e it can access both user and kernal resources.
but in case of user mode it only access to the user resources
instead of accessing system resources also like kernal.
| Is This Answer Correct ? | 5 Yes | 0 No |
How does a user get the current date, time in UNIX?
What does the command ' $who | sort –logfile > newfile' do?
When i run a programm of orphan process. Instead of getting child's parent (ppid)=1 ..i get 1400 and it varies as per system. How can i findthe right soluion??? My pgm: #include<stdlib.h> # include <stdio.h> int main() { int pid; pid=fork(); if(pid < 0) {exit(-1);} else if(pid==0) { printf("Child Process is Sleeping ..."); sleep(10); printf("Orphan Child's Parent ID : %u ",getppid()); } else { printf("Parent Process Completed ... %u ",getpid()); exit(0); } return 0; } Output:
How to replace the exact word in vi editor?? suppose a file contains words like amaze,amazed,amazement in some of the line.But i want to replace only 'amaze' with delight but don't wanna replace amazed or amazement. thanks
6 Answers Polaris, Tech Mahindra,
Explain the read, write, and execute permissions on a UNIX directory.
How does one process we can start an executable file? How to get the PID process, which we started?
What is $0 bash?
What is the basic difference between unix and windows operating systems?
43 Answers Bopro, College School Exams Tests, CTS, IBM, IT-Kids, Priyadarshini, Sybian Technologies, Tolani Maritime,
what is the difference between SED and GREP ? Which one is more better and why?
What is grep short for?
What is the difference between pipe and xargs?
Where can I get the free download of Unix by Yeswant Kanetkar?
Unix Commands 
