Drive letter assignment in DOS/Windows (legacy): Second IDE drive with primary and extended partitions A system has two IDE hard disks. Each disk contains a primary partition and an extended partition with one logical drive. Which drive letter will the operating system assign to the primary partition of the second hard disk?

Introduction / Context:
Legacy DOS and early Windows assign drive letters in a specific order: floppies (A:, B:), then primary partitions, then logical drives in extended partitions. Understanding this order helps with multibooting and data partition planning.

Given Data / Assumptions:

• Two IDE drives (Disk 0 and Disk 1).
• Each has one primary partition and one extended partition that contains one logical drive.
• No removable drives are occupying letters beyond A: and B:.

Concept / Approach:

Classic letter assignment proceeds as follows: C: goes to the primary partition of the first physical hard drive. Next, the system assigns letters to logical drives in the extended partition of the first drive. Only after finishing those does it assign a letter to the primary partition of the second drive, followed by its logical drives. With one logical on the first drive, D: becomes that logical, so the second drive’s primary gets E:.

Step-by-Step Solution:

Verification / Alternative check:

Booting such a system in DOS/Win9x or Windows setup demonstrates this order; disk management tools show letter assignments reflecting the described precedence rules.

Why Other Options Are Wrong:

• C: is already used by Disk 0 primary.
• D: is consumed by Disk 0’s logical drive (given there is one).
• F: belongs to Disk 1’s logical drive after assigning E: to its primary.
• None of the above: incorrect because E: is correct under the stated assumptions.

Common Pitfalls:

Assuming all primary partitions get letters before any logical drives. In legacy DOS/Win9x, logical drives on the first disk are lettered before the second disk’s primary. Modern Windows may behave differently when volumes are hidden or using GPT/UEFI, but the classic exam scenario follows the legacy rule.

Final Answer:

E