CS-451 MIDTERM REVIEW EXAM 36 QUESTIONS
WITH VERIFIED ANSWERS
Privileged instructions are instructions that can only be executed by the Kernel or
a privileged process - CORRECT ANSWER What are privileged instructions?
1. Provide a higher level of security
2. provide different functionality within kernel modes - CORRECT ANSWER Some
CPUs provide for more than two modes of operation. What are two possible uses
of these multiple modes?
1. User makes an I/O request on I/O device
2. I/O device controller sends an interrupt to CPU to handle I/O request
3. CPU stops its current task
4. CPU starts processing I/O request
5. CPU returns results from request or executes request
6. CPU has finished I/O request and resumes previous task - CORRECT ANSWER
What steps does the computing system take to support I/O request by user.
Explain in detail from the initial step of I/O request up to the completion of I/O
An interrupt is a signal emitted by hardware or software when a process needs
immediate attention. - CORRECT ANSWER What are interrupts?
A trap is a software generated signal that either calls OS routines or catches
arithmetic errors - CORRECT ANSWER What are traps?
, 1. A disk is ready to receive more data
2. A keystroke was made on the users keyboard - CORRECT ANSWER give 2
examples of an interrupt
1. Divide by 0 error
2. Invalid memory access - CORRECT ANSWER give 2 examples of a trap
The CPU repeatedly reads, or fetches instructions from memory and then
executes that instruction. - CORRECT ANSWER what role does the CPU play in
executing a program?
reads inputs from the keyboard and scans them to the UI for the program -
CORRECT ANSWER what role does the controller for the Keyboard play when
executing a program?
this is where the program resides for the entirety of its execution - CORRECT
ANSWER what role does the RAM play when executing a program?
provides an interface between the storage device and the OS, enabling the OS to
read and write data to the storage device - CORRECT ANSWER what role does the
disk controller play when executing a user program?
1. Manage the computer's resources
2. Provide services for and execute applications
3. provide a user interface - CORRECT ANSWER What are the 3 main purposes of
an operating system?
WITH VERIFIED ANSWERS
Privileged instructions are instructions that can only be executed by the Kernel or
a privileged process - CORRECT ANSWER What are privileged instructions?
1. Provide a higher level of security
2. provide different functionality within kernel modes - CORRECT ANSWER Some
CPUs provide for more than two modes of operation. What are two possible uses
of these multiple modes?
1. User makes an I/O request on I/O device
2. I/O device controller sends an interrupt to CPU to handle I/O request
3. CPU stops its current task
4. CPU starts processing I/O request
5. CPU returns results from request or executes request
6. CPU has finished I/O request and resumes previous task - CORRECT ANSWER
What steps does the computing system take to support I/O request by user.
Explain in detail from the initial step of I/O request up to the completion of I/O
An interrupt is a signal emitted by hardware or software when a process needs
immediate attention. - CORRECT ANSWER What are interrupts?
A trap is a software generated signal that either calls OS routines or catches
arithmetic errors - CORRECT ANSWER What are traps?
, 1. A disk is ready to receive more data
2. A keystroke was made on the users keyboard - CORRECT ANSWER give 2
examples of an interrupt
1. Divide by 0 error
2. Invalid memory access - CORRECT ANSWER give 2 examples of a trap
The CPU repeatedly reads, or fetches instructions from memory and then
executes that instruction. - CORRECT ANSWER what role does the CPU play in
executing a program?
reads inputs from the keyboard and scans them to the UI for the program -
CORRECT ANSWER what role does the controller for the Keyboard play when
executing a program?
this is where the program resides for the entirety of its execution - CORRECT
ANSWER what role does the RAM play when executing a program?
provides an interface between the storage device and the OS, enabling the OS to
read and write data to the storage device - CORRECT ANSWER what role does the
disk controller play when executing a user program?
1. Manage the computer's resources
2. Provide services for and execute applications
3. provide a user interface - CORRECT ANSWER What are the 3 main purposes of
an operating system?
