what is user mode & kernel mode?
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Answer / mohan l
A process can run in two modes:
1.User Mode.
2.Kernel Mode.
1.User Mode:
=>A mode of the CPU when running a program.
=>In this mode ,the user process has no access to the
memory locations used by the kernel.When a program is
running in User Mode, it cannot directly access the kernel
data structures or the kernel programs.
2.Kernal Mode:
=>A mode of the CPU when running a program.
=>In this mode, it is the kernel that is running on behalf
of the user process and directly access the kernel data
structures or the kernel programs.Once the system call
returns,the CPU switches back to user mode.
When you execute a C program,the CPU runs in user mode till
the system call is invoked.In this mode,the user process has
access to a limited section of the computer's memory and can
execute a restricted set of machine
instructions.however,when the process invokes a system
call,the CPU switches from user mode to a
more privileged mode the kernel. In this mode ,it is the
kernel that runs on behalf of the user process,but it has
access to any memory location and can execute any machine
instruction. After the system call has returned,the CPU
switches back to user mode.
| Is This Answer Correct ? | 74 Yes | 7 No |
Answer / sherin sha
KERNEL-MODE
The kernel-mode programs run in the background, making sure
everything runs smoothly - things like printer drivers,
display drivers, drivers that interface with the monitor,
keyboard, mouse, etc. These programs all run in such a way
that you don't notice them.
When the computer boots up, Windows calls the KERNEL, the
main kernel-mode program that allows all the other programs
to run, even the user-mode programs.
USER-MODE
These are the programs that you run when you want specific
programs - e.g., MS Paint, MS Word, and Calculator. These
are heavily restricted, as to not crash the system. Windows
uses memory-protection services offered by the processor to
prevent malicious programs from interfering with the rest of
the system and corrupting it.
| Is This Answer Correct ? | 64 Yes | 11 No |
KERNEL-MODE
Kernel mode, also referred to as system mode, is one of the
two distinct modes of operation of the CPU in Linux. 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.
USER-MODE
User mode is the normal mode of operating for programs, web
browsers etc. They don't interact directly with the kernel,
instead, they just give instructions on what needs to be
done, and the kernel takes care of the rest. Kernel mode, on
the other hand, is where programs communicate directly with
the kernel. A good example of this would be device drivers.
A device driver must tell the kernel exactly how to interact
with a piece of hardware, so it must be run in kernel mode.
Because of this close interaction with the kernel, the
kernel is also a lot more vulnerable to programs running in
this mode, so it becomes highly crucial that drivers are
properly debugged before being released to the public.
| Is This Answer Correct ? | 32 Yes | 3 No |
Answer / abhay singh naruka
user mode is highly restrictive and has very limited system
resource access, while the kernel mode has no such type of
restrictions.
| Is This Answer Correct ? | 9 Yes | 2 No |
Answer / masoud
Kernel Mode
In Kernel mode, the 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.
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 ? | 4 Yes | 1 No |
Answer / mohan krishnareddy
Kernel Mode:
Kernel Mode is a technology that enables the execution of ordinary user-space programs inside kernel space. This article presents the background, an approach and an implementation of kernel mode.
User Mode:
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 ? | 2 Yes | 2 No |
Answer / nishikant sahu
The term “context Switching” is used to define the user mode
and kernel mode.
If “context Switching” happens while exciting your program
that become kernel mode and if not then it a user mode.
context Switching.. Save the current state of program and
execute the other task.
Suppose in your program if system calls happen then it
should be executed by Kernel so this time “state of the
process” should
Be saved and move to kernel mode.
Nishikant Sahu
| Is This Answer Correct ? | 4 Yes | 5 No |
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