List I List II A. Clustered Page Table I. Generally considered inappropriate for 64 bit architectures. B. Hierarchical Page Table II. Has only entry for each real page (or frame) of memory. C. Segmentation III. Useful for Sparse address spaces. D. Inverted Page Table IV. Supports a user view of the system.
Choose the correct answer from the options given below:
A→III, B→I, C→IV, D→II
Memory Management Techniques Matching Explained
This section provides a detailed explanation for matching the memory management techniques listed in List I with their corresponding descriptions in List II. The goal is to understand the characteristics of each technique.
A Clustered Page Table Explained
Item A: Clustered Page Table is correctly matched with III. Useful for Sparse address spaces.
Explanation: A Clustered Page Table is an optimization strategy primarily used to reduce the overhead associated with large page tables, especially in systems with sparse address spaces. Instead of maintaining individual entries for every single page, it groups entries corresponding to contiguous logical pages. This approach conserves memory, making it highly suitable for sparse address spaces where large blocks of virtual memory might be unused.
B Hierarchical Page Table Explained
Item B: Hierarchical Page Table is matched with I. Generally considered inappropriate for 64 bit architectures.
Explanation: A Hierarchical Page Table structure organizes page tables across multiple levels. This allows for efficient management of large virtual address spaces by allocating memory for page table entries only when needed. In the context of this question's provided matching, this technique is associated with the description 'Generally considered inappropriate for 64 bit architectures'. It's important to note that hierarchical paging is fundamental in modern 64-bit systems, but the provided pairing dictates this specific association for this question.
C Segmentation Explained
Item C: Segmentation is matched with IV. Supports a user view of the system.
Explanation: Segmentation is a memory management approach that divides a program's address space into logical segments based on program structure (e.g., code, data, stack). This segmentation aligns closely with how programmers often structure their applications, thus supporting a user view of the system. It enables logical separation, facilitating features like memory protection and sharing at a segment level.
D Inverted Page Table Explained
Item D: Inverted Page Table is matched with II. Has only entry for each real page (or frame) of memory.
Explanation: Unlike traditional page tables that map virtual pages to physical frames, an Inverted Page Table maintains a single table where each entry corresponds to a physical page frame. The entry details which virtual page (and from which process) is currently stored in that physical frame. Therefore, it contains an entry for each real page (or frame) of memory, making its size dependent on the amount of physical memory rather than the size of the virtual address space.
Summary of Correct Matching
The correct matching between List I and List II is as follows:
| List I Item | Technique Name | List II Item | Description |
| A | Clustered Page Table | III | Useful for Sparse address spaces |
| B | Hierarchical Page Table | I | Generally considered inappropriate for 64 bit architectures |
| C | Segmentation | IV | Supports a user view of the system |
| D | Inverted Page Table | II | Has only entry for each real page (or frame) of memory |
This structured matching helps clarify the distinct roles and characteristics of various memory management techniques used in operating systems.
Important Questions from Memory Management
- A system has a Translation Lookaside Buffer (TLB) that has a reach of 1 MB. TLB reach is defined as the total amount of physical memory that can be accessed through the TLB entries. The paging system uses pages of size 4 KB. The virtual address space is 64 GB and physical address space is 1 GB. If each TLB entry stores a 4-bit process id, page number, frame number, and a 2-bit control field, then the size of the TLB (in bytes) is ___________. (answer in integer)
Note: 1K=$2^{10}$, 1M=$2^{20}$, 1G=$2^{30}$ - Consider contiguous allocation of physical memory to processes using variable partitioning scheme. Suppose there are 8 holes in the memory of sizes 20 KB, 4 KB, 25 KB, 18 KB, 7 KB, 9 KB, 15 KB, and 12 KB. Assume that no two holes are adjacent. Two processes P1 of size 16 KB and P2 of size 9 KB arrive in that order, and they are allocated memory using the best-fit technique. After allocating space to P1 and P2, the number of holes of size less than 8 KB is ____________. (answer in integer)
Note: 1K=$2^{10}$ - Choose the correct answer.
In memory management, page size is always, power of 2. Which of the following is a type of memory and is similar to RAM?
200 μs should be the memory size of a digital storage oscilloscope to be able to record a transient of 10 seconds with a time resolution of 200 μs?
