File organization methods: what does “sequential organization” of records mean in classical file systems?

Computer Science System Analysis and Design Difficulty: Easy
Choose an option
  • A
    Storing records in key order in contiguous/sequential fashion
  • B
    Storing records sequentially but using an index to locate records (indexed sequential)
  • C
    Using an index for each different key type (multiple indexes)
  • D
    Placing records randomly throughout the file (random organization)
  • E
    Hashing records to buckets based on a hash key

Answer

Correct Answer: Storing records in key order in contiguous/sequential fashion

Explanation

Introduction / Context:Classical file organizations include sequential, indexed-sequential, random (hash), and others. Understanding these patterns helps match workloads (batch vs interactive) to storage structures.

Given Data / Assumptions:

  • Sequential organization emphasizes ordered storage by a key.
  • Indexed-sequential adds an index for faster access.
  • Random/hash places records non-contiguously based on a hash function.

Concept / Approach:In pure sequential organization, records are arranged in order (e.g., ascending key). Access patterns are typically sequential scans, which work well for batch processing and range reports.

Step-by-Step Solution:1) Identify the defining property: sorted, contiguous/sequential record layout.2) Distinguish from indexed-sequential, which introduces auxiliary indexing.3) Distinguish from random/hash, which distributes records unpredictably for constant-time access.4) Choose the option describing ordered contiguous storage.

Verification / Alternative check:Textbook definitions align sequential with ordered scans and high throughput for large, ordered reads.

Why Other Options Are Wrong:(B) describes indexed-sequential, not pure sequential. (C) refers to multiple indexes design. (D)/(E) describe random/hash organizations.

Common Pitfalls:Confusing sequential with indexed-sequential due to similar names; the index changes access characteristics.

Final Answer:Storing records in key order in contiguous/sequential fashion.

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