From 116d9d96dd6cffb4b4cae53e23e8a3d29ece604b Mon Sep 17 00:00:00 2001 From: mo khan Date: Mon, 8 Feb 2021 10:46:22 -0700 Subject: describe modes of operation --- doc/assignment1.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/doc/assignment1.md b/doc/assignment1.md index 353e9f2..75324df 100644 --- a/doc/assignment1.md +++ b/doc/assignment1.md @@ -131,6 +131,16 @@ Instructions: Please answer the following questions in complete sentences. Your The users and clients of the applications see only a brief interruption of service. 1. Describe an operating system's two modes of operation. + + kernel mode: executes tasks on behalf of the operating system. + user mode: executes tasks on behalf of the user. + + Whenever the operating system gains control of the computer, it is in kernel mode. + The dual modes of operation provides a way for protecting the operating system + from malicious behaviour. Instructions that can cause harm are treated as + privileged instructions. Privileged instructions can only be executed in + kernel mode. + 1. Define cache, and explain cache coherency. 1. Describe why direct memory access (DMA) is considered an efficient mechanism for performing I/O. 1. Describe why multicore processing is more efficient than placing each processor on its own chip. -- cgit v1.2.3