CODEWITHSUNDEEP
kernelprotectedmode
Alex
Alex

Reputation: 51

What is the difference between user/kernel mode and protected/real mode? Are they the same?

After I read about these concepts, it seems that both user/kernel modes and real/protected modes were intended for protection purposes. Basically these modes are differentiated to prevent crash of one program by another. So why use different terms for one and the same thing?

Upvotes: 5

Views: 1528

Answers (1)

Tsyvarev
Tsyvarev

Reputation: 66298

These terms are different. Moreover, both user and kernel OS modes are related to protected processor's mode.

User mode and kernel mode are modes of the process from the view of the operating system. Same process can switch modes many times during system uptime.

Real mode and protected mode are modes of the processor (usually these modes refer to x86 family). Switch from real to protected mode is performed once during system startup. All futher instructions are executed in protected mode. (I am not sure, whether additional switch to real mode is perfomed on system shutdown.)

Upvotes: 8

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