Disk partitioning (MBR scheme): How many extended partitions can be created on a single MBR-partitioned drive?

Introduction / Context:
On legacy MBR-partitioned disks, partition types and limits are a frequent source of confusion. Understanding the roles of primary, extended, and logical partitions is essential when setting up dual-boot systems or older servers.

Given Data / Assumptions:

• The disk uses the MBR (Master Boot Record) partitioning scheme, not GPT.
• We are discussing the number of extended partitions specifically.
• Logical partitions reside inside an extended partition.

Concept / Approach:

MBR allows up to four primary partitions. To overcome that limit, one of those entries can be designated as an extended partition, which then contains a linked list of logical partitions. By design, there can be only one extended partition per disk, but it can hold many logical partitions (for example, /dev/sda5, /dev/sda6, ...).

Step-by-Step Solution:

Verification / Alternative check:

Tools like fdisk or parted show partition tables; on MBR disks you will observe at most one extended partition (type 0x05/0x0F) containing any number of logical partitions beyond four total partitions.

Why Other Options Are Wrong:

• 16, 4, 2: These numbers relate to other limits (for example, four primaries), not the count of extended partitions.
• None of the above: Incorrect because exactly one extended partition is allowed.

Common Pitfalls:

Confusing the number of logical partitions (which can be many) with the number of extended partitions (always one at most). Also, mixing MBR rules with GPT (GUID Partition Table), which uses a different model and does not require extended partitions.

Final Answer:

1