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

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.