In basic computer hardware terminology, which type of hard drives are permanently located inside the system unit and are not designed to be removed during normal use, except when they need to be repaired or replaced?

Introduction / Context:
This question focuses on basic categories of storage devices in a personal computer. Hard drives can be mounted inside the computer case or attached externally using cables. Understanding the distinction between internal and external drives helps you interpret diagrams, read technical documentation and manage storage more effectively.

Given Data / Assumptions:

• The drives described are permanently located inside the system unit.
• They are not meant to be removed in everyday operation.
• They are removed only for repair, upgrade or replacement.
• Options include static, internal, external, removable and portable hard drives.

Concept / Approach:
The hard drive that is fixed inside the computer case and connected directly to the motherboard and power supply is called an internal hard drive. It normally holds the operating system and user data and remains inside the case at all times. External or portable drives are designed to be plugged in and removed easily through ports such as USB. Removable hard drives are built for frequent insertion and removal, for example in some server systems. Static is not a standard term used to categorise hard drives.

Step-by-Step Solution:
Step 1: Read the description carefully. The hard drives are permanently located inside the system unit. Step 2: They are not designed to be unplugged or carried around by users during normal use. Step 3: Think of the usual drive that comes preinstalled in a desktop or laptop, containing the operating system. This is an internal hard drive. Step 4: External hard drives, in contrast, are connected by cables and are meant to be portable and removable. Step 5: Removable or portable drives explicitly highlight removable use, so they do not match the always inside description. Step 6: Static hard drives is not a recognised category in standard textbooks and is likely a distractor. Step 7: Therefore, the correct answer must be internal hard drives.

Verification / Alternative check:
When you open a computer case or look at laptop specifications, the main storage device is listed as internal HDD or internal SSD. Manuals refer to it as an internal hard drive or internal storage. External drives are sold as accessories, usually with enclosures and cables. Technical diagrams show the internal drive mounted inside the system chassis, confirming that the phrase permanently located inside the system unit refers to internal hard drives.

Why Other Options Are Wrong:
Static hard drives is not standard technical terminology and does not appear in basic computer hardware classifications. External, removable and portable drives all stress the idea of being easily disconnected, which conflicts with the description of being permanently housed inside the system unit and only removed for repair or replacement.

Common Pitfalls:
Learners sometimes confuse internal versus external with hard disk versus solid state disk. These are different classification dimensions. Internal and external describe physical placement, while hard disk and solid state describe technology. In exam questions, focus on the location and usage described to choose internal or external correctly.

Final Answer:
Hard drives that are permanently located inside the system unit are called internal hard drives.