OSG202 - Chapter 1

Which of the following statements is incorrect about user mode and kernel mode?

• In kernel mode, the OS can execute every instruction in the instruction set

• In user mode, user program can execute only a subset of instructions

• Having two modes of operation helps prevent user programs from accessing critical instructions

• None of the above

The four main structural elements of a computer system are:

• Processor, Registers, I/O Modules, Main Memory

• Processor, Registers, Main Memory, System Bus

• Processor, Main Memory, I/O Modules, System Bus

• None of the above

What is not correct about system calls?

• A system call allows a user process to assess and execute operating system functions inside the kernel.

• User programs use system calls to invoke operating system services

• In terms of performance, using system calls is better than using procedure calls

• Every system call involves overhead due to context switch

The general role of an operating system is to:

• Act as an interface between various computers

• Provide a set of services to system users

• Manage files for application programs

• None of the above

Random Access memory:

• Is typically faster than cache memory

• Is volatile

• Can only be read sequentially

• Stores all the files on the computer

What is the main characteristic of embedded operating system?

• Multiple CPU

• Time-sharing

• Many I/O devices

• Restriction of memory size, speed of CPU, screen size, powers

Which is the difference between personal computers and mainframe computers?

• Mainframe computers are mostly batch systems with many users

• Personal computers are always interactive

• Protection is much more important on mainframe computers

• All of the above

____ is the partitioning of a single server, each of which can support a different operating

• Multiprocessing

• Multithreading

• Shared processing

• Virtualization

A CPU may have multiple execution units, so that can carry out multiple instructions in the same time is called:

• Pipeline

• Superscalar

• Multicore

• None of the other choices

Which of the following instructions should be allowed in user mode?

• Disable all interrupts

• Read the time-of-day clock

• Set the time-of-day clock

• Change the memory map