Given a file system with very large files and limited inode size, which approach is better to optimize random access performance: increasing direct pointers or increasing levels of indirect pointers? Why?
AIncreasing direct pointers is better because it reduces the number of pointer indirections for large files
BIncreasing indirect pointer levels is better because it allows addressing larger files without increasing inode size
CIncreasing direct pointers is better because it reduces inode size and improves cache locality
DIncreasing indirect pointer levels is better because it reduces the number of disk seeks for small files
Step-by-Step Solution
Solution:
Step 1: Consider inode size constraints
Inode size is fixed, so increasing direct pointers reduces space for other metadata.
Step 2: Analyze addressing large files
Indirect pointer levels allow addressing very large files without increasing inode size.
Step 3: Evaluate random access performance
While direct pointers reduce indirection, they cannot cover very large files. Indirect pointers add indirection but enable scalability.
Step 4: Assess options
Increasing indirect pointer levels is better because it allows addressing larger files without increasing inode size correctly balances inode size and large file addressing. Increasing direct pointers is better because it reduces the number of pointer indirections for large files ignores inode size limits. Increasing direct pointers is better because it reduces inode size and improves cache locality incorrectly claims direct pointers reduce inode size. Increasing indirect pointer levels is better because it reduces the number of disk seeks for small files incorrectly associates indirect pointers with fewer disk seeks for small files.
Final Answer:
Option B -> Option B
Quick Check:
Indirect pointers scale large files without inode size increase [OK]
Quick Trick:Indirect pointers scale large files; direct pointers limited by inode size [OK]
Common Mistakes:
MISTAKES
Assuming direct pointers can scale large files or reduce inode size
Trap Explanation:
PITFALL
Candidates confuse inode size limits and the scalability benefits of indirect pointers.
Interviewer Note:
CONTEXT
Tests trade-off reasoning for inode design in large file scenarios.
Master "Inode Structure - File Metadata & Block Pointers" in Operating Systems
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