Chapter 1 & 2

Identify the correct order in which a command line interpreter executes the following steps when it runs an external command.

1. read from the terminal 2. interpret the command and execute 3. create a child process 4. wait for the program

(T/F) A modular OS can load kernel modules dynamically and executes them in separate processes, like a microkernel does.

False

(T/F) In general memory used to implement the cache has larger capacity and is cheaper then the memory that stores the data.

False

(T/F) It is not feasible on any system to store the entire OS in firmware

False

(T/F) On MS-DOS, cmd.exe executes another program by creating a child process and then overloading the program over it.

False

(T/F) Windows and Mac OS X allow users more flexibility to change system policies than Linux.

False

Why was a shell added to the MAC OS X?

MAC OS X uses a UNIX-like kernel

Which of the following operating systems are open source?

NetBSD & Linux

(T/F) A Unix shell can start a program to run in the background (in parallel) by appending an '&' to the command line

True

(T/F) A single user (dedicated) machine is in general easier to secure than a multiuser multitasking system.

True

(T/F) Batch operating systems do not schedule another process on the CPU during an I/O operation.

True

(T/F) Operating systems may provide multiple file system types.

True

(T/F) Unix treats devices similar to files and has system calls that work similarly for both

True

Where were GUIs first practically developed?

XEROX PARC

What is a core dump on Unix-type of kernels?

a copy of a process' memory content at the moment it crashed that is saved to nonvolative memory and can be used to debug it later

In a Symmetric Multiprocessor (SMP) all CPUs

are peers and execute the same operating system

The program that runs at all times on the computer is called the ________.

kernel

An OS that would move nonessential components from the kernel and run them in userlevel processes is a...

micorkernel OS

For which of the following systems is screen size a challenging problem for system designers?

smartphones

A multicore system looks to the operating system just like a....

symmetric multiprocessor system

A _______ call provides processes access to OS services.

system

What is not a function of an operating system?

to solve scientific problems

Which of the following is a privileged instruction that can be executed only in kernel mode ?

turn off interrupts

Select the applicable statements for the layered OS architecture

- a layer can only use services provided by lower layers - simplifies construction and debugging - less efficient than a non-layered OS because a system call may involve repeated calls through the layers, necessitating repeated parameter copies and modifications - defining the layers can be difficult because of circular dependencies between OS subsystems (e.g. CPU scheduling and backing-store driver)

When does the OS switch the CPU to kernel mode?

- a process executes a system call - the CPU receives an interrupt

The switch from a single processor to a multiprocessor system provides the following advantages:

- increases system reliability and provides graceful degradation - reduces execution time for applications running in parallel

Which of the following are operating system services?

- inter-process communication via shared memory - keeping track of how long each process runs on a CPU - user authentication at login

Which are characteristics of shared memory interprocess communication?

- requires protection and synchronization - faster than message passing - more difficult to implement for intercomputer communication

What are some advantages of separating mechanism from policy in operating system design?

- user can change how the OS kernel behaves (e.g. CPU scheduling) without having to recompile it - increased flexibility: can change policies without having to update the mechanisms - could make the OS scale for increased demand and additional resources (e.g. more memory, additional CPUs) without the need to reinstall/recompile the kernel

Identify the methods used to pass parameters to a system call.

- using registers - using a block memory - on the stack

Indicate the order for the following operations as they occur at system boot time for a Linux OS

1. bootstrap program (from firmware) runs system diagnostics 2. bootstrap program reads the boot block and executes the code 3. boot block code loads the full bootstrap program (GRUB) 4. the operating system file is located on the bootable partition, loaded in memory and executed

The following steps represent different phases of a HDD read input operation executed using DMA. Select the correct order (in time) in which these steps execute.

1. process executes a read system call 2. HDD device driver initiates read operation 3. read operation on the HDD completes 4. data from the HDD is transferred to memory using DMA method 5. HDD controller sends interrupt to CPU

The _________ program is stored in ROM or firmware. It initializes the hardware and then it loads the operating system.

bootstrap

A system consisting of web browsers and web servers where web browsers load HTML pages with content from multiple servers is an example of a ...

client-server system

What is the shell (in Unix)?

command-line interpreter