What does a fence register primarily protect?

Disk

Infrastructure

Memory

CPU

Database

What does chmod $755$ file.txt do$?($Select Three.$)$

Read, write, and execute $($user owner$).$

Read and execute permissions $($others$).$

Read, write, and execute $($others$).$

Read and execute $($user owner$).$

Read and execute permissions $($group owner$).$

What are the differences between a multitasking and multiprocessing OS$?$