DIRECTIONS: Read each question carefully. Then click on the dot next to the answer that most closely fits the question. Try to answer all questions on this quiz and when you are done, click on the grade me button at the bottom.

1. Which statement below is false?

the operating system is just a program
certain instructions can only be done when the computer is in privileged mode
user programs can get into either privileged or user modes
there exists a flip-flop in the hardware that indicates the current mode

2. What do we call an instruction that asks the operating system to do something for another program?

trap
interrupt
mode switch
privileged command

3. Which of the following are possible views of the operating system?

as a service provider
as a governor or police cop
a bundle of services and subroutines that all programs can use
all of the above

4. What do IBM mainframes call the special instruction that switches into more privileged mode?

TRP
SVC
SWT
CAL

5. In addition to being able to perform any instruction of the computer's instruction set, what else does being in privileged mode allow a program to do?

change the contents of any register
add new instructions to the instruction set
reconfigure the internal buses
switch off protection so that user programs can do anything

6. What do we call the act of a user program requesting that the operating system do something on its behalf?

mode switch
system call
entry point
abend

7. Which instruction is TRP most like?

JMP
HLT
RET
CAL

8. What do we call a well-defined place at which a user program can "enter" the operating sytem and begin a subprogram of the OS?

entry point
abend
mode switch
system call

9. What do we call the "user" who can log in with full privileges on a UNIX system?

the group
root
the world
anonymous

10. What is another name for this special privileged user?

superman
superior
superordinate
superuser

11. What is usually the first thing that the operating system code does when a user program initiates a system call?

checks the validity of the parameters
switches the mode to privileged so the code can do anything from this point on
jumps to the actual code that implements the system call
abends the program

12. What do we name people who try to break into computer systems for whatever reason?

spies
roots
hackers
users

13. What is a weakness of the von Neumann architecture that requires there be privileged and unprivileged modes?

you can have as many ALUs as you want to speed up processing
you can jump to any location in memory
you can have as large a main memory as you want
you can go beyond the bounds of normal arithmetic and cause overflow

14. When a UNIX user program wants to read some data from a file, it issues a read system call. This gets turned into a small chunk of code that sets up the call and then invokes the operating system. Which instruction should replace the question marks in the box?

TRP 2
TRP 3
CAL 1075
CAL 1244
JMP 1075
JMP 1244