WGU - C191

What is the role of the OS?

To manage a computer's hardware

Which OS service provides functions that are helpful to the user?

Program execution

Which OS service provides functions that are helpful to the user?

Program execution

Which system call is used for device manipulation?

ReadConsole()

Which system calls can be grouped under the category of process controls?

Allocate, free memory

Which service function is responsible for identifying and correcting exceptions such as the lack of paper in a

printer?

Error detection

Which type of OS service uses the CLI?

User interface

What represents layer zero (0) in the layered approach?

Hardware

What is a disadvantage of booting an OS stored in ROM?

Changing a bootstrap requires new hardware chips.

What is a valid process state?

Waiting

What are two valid components of a process control block (PCB)?

The process counter & The process state

What is the difference between kernel and user threads?

Kernel threads are directly managed by the operating system, whereas user

threads are managed without kernel support.

Which advantage does short-term scheduling have compared with long-term scheduling?

It takes less time to select a process to execute next.

What is considered stable when the average rate of process creation is equal to the average departure rate

of processes leaving the system?

The degree of multiprogramming

Which action allows an application that is in the background to be passed to the foreground and vice versa?

Memory reload

What is the process of context switching?

Performing a state save and a state restore

Which features are included in the DTrace tool?

Compiler, providers of probes, and consumers

What is the difference between cooperative and preemptive scheduling?

Cooperative scheduling occurs when a process terminates, whereas preemptive

scheduling occurs when a process initiates.

Which scheduling criteria measures the number of processes completed per time unit?

Throughput

Which criterion attempts to keep the processor as busy as possible?

CPU utilization

When does starvation occur in the priority scheduling algorithm?

When a process is waiting indefinitely

Which scheduling algorithm was designed especially for time sharing systems?

Round-robin

What is a difference between soft and hard processor affinity?

Hard affinity specifies a subset of processors on which a process may run, whereas

soft affinity leaves the processor selection to the OS.

What is an address that is generated by the CPU?

A logical address

Which general-purpose storage is accessed directly by the CPU?

The main memory

What is a limitation of swapping on mobile systems?

Applications that fail to free up sufficient memory are terminated.

What is the name of the memory allocation scheme where the operating system keeps a table of available

holes?

Variable partition

What is described as memory allocated from a fixed-size segment consisting of physically contiguous pages?

Buddy system

Which memory management solution relocates all available memory into one variable-sized block?

Compaction

What does the 50-percent rule of memory fragmentation state when allocating additional memory using the

first-fit method?

One-third of all memory may be unused.

Which component is associated with the paging scheme?

Frames

Which solution resolves slow access time to user memory location when implementing paging?

Using the translation look-aside buffer (TLB)

Which component ensures the integrity of memory in a paged environment?

Protection bits

What is a non-self-modifying code that never changes during execution?

Reentrant

What is the purpose of an inverted page table?

It reduces memory usage to store addresses.

What is a benefit of using virtual memory?

System libraries can be shared.

Which algorithm has the lowest possible page-fault rate and does not suffer from Belady's anomaly?

Optimal

Which collection of pages references the most recent set of delta parameters (Δ)?

The working set

In Windows, what represents the shared-memory object that will enable communication between

processes?

A memory-mapped file

Which strategy for assigning kernel memory uses cache to refer to a set of one or more physically contiguous

pages that serve for each unique kernel?

Slab allocation

What is a scheme used to help free up space (i.e. garbage collection)?

Least frequently used (LFU)

What will collect free space (i.e., garbage collection) together to provide more usable space?

Compaction

What is the smallest unit of data transfer in a physical hard disk drive?

Block

How is the array of logical blocks mapped onto the hard disk?

Onto the sectors of the disk sequentially

What is the average latency of a typical hard disk?

3 milliseconds

What is the rate at which data flows from the hard disk to the computer?

Transfer

What is a benefit of creating a separate raw partition for use as swap space?

It is optimized for speed of access.

What is a stored data condition that can prevent other processes from gaining access to it?

File locking

Which access type is used when speed is important in linked allocation files?

Sequential access

How do code editors and code compilers usually access files?

Sequential access

What are two key types of access permissions?

Append & List

Which mounting model allows a computer to mount file systems from remote machines?

Client-server

What is the I/O bus standard that connects the processor-memory subsystem to the fast devices?

PCI

What is memory-mapped I/O?

Memory addresses reserved for device registers

Which protection goal is achieved by detecting latent errors at the interfaces between components

subsystems?

Improving reliability

How can protection improve the reliability of a system?

By detecting errors at the interfaces between component subsystems

What is an example of a policy?

User access

How do policies and mechanisms differ?

Policies may change from place to place whereas mechanisms remain the same.

What can be assigned roles when using role-based access control?

The program & The process

Several major retail chains are hacked and customer information is stolen, including credit card numbers.

Which type of attack has occurred?

Breach of confidentiality

Which security level is identified by gathering information through malicious phone calls?

Human