18 Questions
What is the main purpose of demand paging in operating systems?
To efficiently manage memory resources by loading pages from secondary storage into primary memory only when needed
What happens when a page fault occurs in demand paging?
The operating system locates a free page in memory, transfers the requested page from secondary storage, updates the page table, and resumes the interrupted program
How does demand paging help in overcoming the limitations of main memory size?
By loading pages from secondary storage into primary memory only when needed
What is one benefit of demand paging in terms of resource allocation?
Improving memory utilization by accommodating more processes in main memory
How does demand paging impact the initial overhead involved in loading a program into memory?
It reduces the overhead by loading only essential pages initially
In demand paging, what occurs when a process requests access to a page that is not in memory?
A page fault occurs, and the operating system locates a free page in memory for the requested page
What is the purpose of the substring() method in Java?
Extracts a portion of a string based on the specified indices
Which method is used for splitting a string into multiple parts based on a defined pattern?
split()
What does the concat() method do when used to concatenate strings in Java?
Adds a new string to an existing one without modifying the original string
Why are strings considered immutable in Java?
To avoid unexpected behavior due to automatic conversion rules
Which method can be used to retrieve the character at a specific index within a string?
charAt(index)
What does the length() method in Java return?
The number of characters in a string
What is the output of the following code snippet? String str = "Hello"; System.out.println(str.charAt(4));
o
Which of the following statements about string comparison in Java is correct?
The compareToIgnoreCase() method compares two strings lexicographically, ignoring case differences.
What is the result of the following operation? "Hello " + "World"
A new string object "Hello World" is created.
Which of the following methods can be used to split a string into an array of substrings?
split()
What is the output of the following code snippet? String str = " Hello World "; System.out.println(str.trim());
"Hello World"
Which of the following statements about string concatenation in Java is true?
Concatenating strings using the + operator is more efficient than using the concat() method.
Study Notes
Demand Paging
Demand paging is a strategy used by operating systems to efficiently manage memory resources in computers. It involves loading pages from secondary storage (like hard drives or solid-state drives) into primary memory (Random Access Memory or RAM) only when they are needed, rather than loading all pages into memory immediately. This approach helps in overcoming limitations of main memory size and increasing efficiency by utilizing the slower secondary storage for infrequently accessed data.
In demand paging, the operating system keeps track of which pages are currently in memory and which are not. When a process requests access to a page that is not in memory, a page fault occurs. The operating system then locates a free page in memory, transfers the requested page from secondary storage to the identified free page, updates the page table, and resumes the interrupted program.
The benefits of demand paging include improved memory utilization and reduced memory pressure. Since not all pages are loaded at once, more processes can be accommodated in the main memory, leading to better resource allocation and overall system performance. Additionally, demand paging reduces the initial overhead involved in loading a program into memory, as only essential pages are loaded initially.
However, while demand paging offers many advantages, it is not without drawbacks. There is a delay associated with each page fault, as the memory system must retrieve the required page from secondary storage. Furthermore, excessive page faults can lead to a phenomenon known as thrashing, where the system spends too much time swapping pages between memory and secondary storage, causing performance degradation.
Learn about demand paging, a memory management strategy used in operating systems to efficiently manage memory resources. Explore how demand paging helps overcome main memory size limitations by loading pages from secondary storage into RAM only when needed.
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