Operating Systems Concepts: Key Questions and Answers
Process States: Active but Not Running
Which of the following alternatives represents the state of the processes that are active but not running?
Wait Time.
Kernel Definition
Definition: A set of basic routines whose mission is to manage the processor, memory, and other resources. Provides for:
Kernel.
Multiprogramming Concept
The concept of Multiprogramming relates to:
The CPU executes various tasks, alternating between them, optimizing the use of the CPU.
Process Definition
Which of the following statements defines what is a process?
Any activity that requires the attention of the CPU utilization of a machine.
Operating System Service Exclusion
Which of the following items is not part of an operating system service?
Acceleration of the calculations.
System Call Concept
The system call concept refers to the communication interface between:
A program that is running and the operating system.
CPU Scheduling Policy: SRTF
CPU scheduling policy, which is to serve the process considering the time they still remain to be implemented. This definition corresponds to:
SRTF.
Round Robin (RR) CPU Scheduling
How does the CPU scheduling policy Round Robin (RR) work?
Gives each process running a specified period of time. If, at the end of that time, the process has not finished, it returns to the end of the queue of ready processes.
Invalid Process Transition
Regarding the states of a process, which of the following transitions cannot occur?
From prepared to frozen.
Active Wait vs. Wait
What is meant by Active Wait and Wait, respectively?
The first process does not block while waiting to enter its critical section, whereas in the latter processes are blocked.
Concurrency Concept Exclusion
Which of the following alternatives is not related to the concept of concurrency?
Two or more processes may be executed in exactly the same instant of time, sharing data and resources.
Deadlock Conditions
What are the 4 conditions to be met for the existence of deadlock?
Circular wait, no preemption, hold and wait, mutual exclusion.
Worst-Fit vs. Best-Fit Memory Allocation
What is the difference between the worst-fit placement policy with respect to the memory allocation policy Best Fit?
Worst fit allocates space from the largest available memory block, while Best fit allocates memory space that is closest to the size of the process.
System Access Control
Which of the following alternatives can control access to a system to increase its security?
Login.
Policies and Mechanisms
The concepts of policies and mechanisms are related to:
The first defines what actions can be performed on system resources, the second identifies ways to carry out such actions.
User Access Profile
What should be the access profile of a user who normally prints, performs clerical tasks, and has access to the internet?
Conventional User.
Process Control Block Functionalities
Which of the following alternatives represents functionalities of the Process Control Block?
State of the process, used files, resources that the process is consuming.
Computer System Threats
What types of threats may a computer system suffer?
Viruses, Hackers, Trojan Horses, Sabotage.
Secondary Storage Access Mechanisms
The mechanism(s) for accessing secondary storage media (files and directories) is (are):
Sequential and Direct.
Virtual Memory Concept
Which of the following is more representative of the Virtual Memory concept?
The set of all directions given by the processor.
Segmentation Technique
Segmentation is a technique that is used to:
- Solving the problems caused by paging
- Distribute the main storage into segments of variable size
Only a) and b)
LRU Algorithm
The LRU algorithm is one that:
Replaces the page that is no longer used.
Swapping
Exchanging pages, segments, or entire programs between RAM and disk is known as:
Exchange or swapping.
Memory Management Without External Fragmentation
Which of the following methods of memory management has no external fragmentation?
Variable Partitions.
Combined Systems: Incorrect Statement
In the context of combined systems, which of the following statements is INCORRECT:
Paged segmentation and segment paging are synonymous.
Demand Paging Hardware Operation
In demand paging, which of these operations is provided by the hardware?
Translation of logical address to physical address.
Shared Data Accesses
When a process’s shared data accesses are said to be modifiable, they are found at:
A critical section.
Static Address Reallocation
Reallocation takes place during static address:
The compilation or load the program into memory.