MCA Entrance Previous Year Question Bank

Dynamic Partition Allocation Maths

List-I (Allocation Scenario)

A. Best-Fit Trap

B. Worst-Fit Benefit

C. First-Fit Advantage

D. 50-Percent Rule

List-II (Resulting System State)

1. Leaves behind tiny, unusable fragments of free memory

2. Leaves behind large leftover holes that are easy for other processes to reuse

3. Fast execution; avoids searching the entire memory layout

4. Given ($N$) allocated blocks, another ($0.5N$) blocks are lost to fragmentation

Protection and Shared Pages

List-I (Paging Flag)

A. Valid-Invalid Bit

B. Read-Only Flag

C. Shared Page Rule

D. Page Table Base Register

List-II (Access Enforcement Duty)

1. Valid means page is in RAM; invalid means page is not in the address space

2. Restricts target memory blocks to reading, protecting code sections from edits

3. Shared pages must be reentrant (read-only, self-contained code)

4. Points directly to the location of the active page table in memory

Segmentation Architecture

List-I (Segmentation Layout)

A. Segment Representation

B. Segment Table Entry

C. Segment Trap Error

D. Shared Segments

List-II (Mapping Property)

1. Maps logical views (methods, stacks, variables) to variable-length segments

2. Contains a base physical address and a segment length limit

3. Raised automatically if a program requests an offset larger than the segment limit

4. Allows processes to share common code sections (like utility libraries) safely

Page Table Structure Variations

List-I (Page Table Design)

A. Hierarchical Paging

B. Hashed Page Tables

C. Inverted Page Table

D. Clustered Page Table

List-II (Memory Saving Strategy)

1. Splits the page table into multiple levels to avoid keeping all parts in memory

2. Maps virtual page numbers to a hash bucket list; common for address lengths >32 bits

3. One entry per physical frame rather than per virtual page; slashes overhead

4. Similar to hashed tables, but each entry points to a block of contiguous pages

TLB Cache Math & Principles

List-I (TLB Metric)

A. TLB Hit Ratio

B. TLB Miss Penalty

C. Effective Access Time

D. TLB Flush

List-II (Operational Meaning)

1. Percentage of times a page number is found in the TLB cache

2. Extra time needed to query the main memory page table on a cache miss

3. Total average memory speed calculation ($\text{EAT}=2\times \text{Memory Speed}-\text{Hit}\times \text{TLB Speed}$)

4. Clears the TLB cache during context switches to protect process memory

Address Binding Timelines

List-I (Binding Phase)

A. Compile Time

B. Load Time

C. Execution Time

D. Hardware Requirement

List-II (Resulting Address Format)

1. Generates absolute physical addresses; code cannot be relocated

2. Generates relocatable addresses; absolute addresses are bound when loaded

3. Bound during runtime; process can move across memory segments

4. Run-time binding requires explicit memory-mapping hardware (MMU)

Linking and Loading Mechanisms

List-I (Linking/Loading Style)

A. Static Loading

B. Dynamic Loading

C. Static Linking

D. Dynamic Linking

List-II (Execution Context / Behavior)

1. Entire program and data are loaded into memory before execution begins

2. A routine is not loaded until it is called; improves memory efficiency

3. System libraries are combined into the final executable image

4. Postpones library linking until runtime; uses stubs to find shared objects

Paging Basic Mapping

List-I (Paging Division)

A. Logical Memory Chunk

B. Physical Memory Chunk

C. Page Number ($p$)

D. Page Offset ($d$)

List-II (Hardware Block Mapping)

1. Page (fixed-size logical block)

2. Frame (fixed-size physical block)

3. Used as an index into the process page table

4. Combined with base address to define the physical location

Dynamic Allocation Strategies

List-I (Placement Strategy)

A. First-Fit

B. Best-Fit

C. Worst-Fit

D. Next-Fit

List-II (Block Selection Rule)

1. Allocates the first free block that is large enough

2. Allocates the smallest free block that is large enough

3. Allocates the largest free block available, leaving a large leftover chunk

4. Similar to First-Fit, but starts searching from the location of the last allocation

Fragmentation Types

List-I (Fragmentation Class)

A. Internal Fragmentation

B. External Fragmentation

C. Compaction

D. Paging Solution

List-II (Root Cause / System Condition)

1. Memory block allocated to a process is larger than requested

2. Total free memory is sufficient, but it is split into small, non-contiguous blocks

3. Shuffling memory contents to place all free blocks together in one large chunk

4. Eliminates external fragmentation by allocating fixed-size blocks