← IGCSE Computer Science Paper 1

Hard disk drive (HDD)

Hard disk drive: a magnetic storage device with spinning platters and moving read/write heads. It gives large capacity at low cost, but is slower and more fragile than flash.

Part of: IGCSE Computer Science 0478 — 3.3 Data Storage — Module 11

Understanding Hard disk drive (HDD) in IGCSE Computer Science Paper 1

What it does: The spinning platters and moving read/write heads are the moving parts. They make an HDD slower than flash and easier to damage if dropped. HDDs store a lot of data cheaply, which is why they are used in desktops, laptops and servers that need big storage. The moving parts are the key weakness of an HDD. A solid-state drive has no moving parts.

Common mistakes: An HDD has moving parts: spinning platters and moving read/write heads. The line should be moving_parts = True. The read/write heads of an HDD move across the platters. They are not fixed. It should be heads = "moving".

Class: _____________________ · Name: _____________________ · Date: _________

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This module's key terms are also in a printable crossword (Modules 304–313) and word search (Modules 304–324).

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Learning

Duo

Which describes how a hard disk drive stores data?

With floating gates in flash chipsMagnetically, on spinning platters

Matches

An HDD has no moving parts, so it is faster than flash.

↓

An HDD does have moving parts (spinning platters and moving read/write heads). This makes it slower and more fragile than flash, not faster.

Applying

Meanings

Term

HDD

Meaning

Hard disk drive: a magnetic storage device with spinning platters and moving read/write heads. It gives large capacity at low cost, but is slower and more fragile than flash.

Practice

HDD = hard disk drive

Testing

Gaps

An HDD stores data on spinning .

Check Answer

Spots

2storage = "magnetic"

3moving_parts = False

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Quick Questions

1. Which describes how a hard disk drive stores data?

A. Magnetically, on spinning platters ✓

B. With floating gates in flash chips

An HDD stores data as magnetic patterns on spinning platters. Floating gates are used in solid-state (flash) storage.

2. What reads and writes data on an HDD?

A. A moving read/write head ✓

B. A laser reading pits and lands

HDDs use read/write heads that move over the platters. Lasers are used for optical discs such as CDs and DVDs.

3. Compared with an SSD, an HDD is usually...

A. Slower and more fragile ✓

B. Faster and more durable

HDDs have moving parts, so access is slower and a knock can damage them. SSDs have no moving parts.

4. Why do many servers and desktops still use HDDs?

A. They have no moving parts

B. Large capacity at low cost ✓

HDDs give plenty of storage for a low price per gigabyte. They do have moving parts, which is why the second answer is wrong.

5. Which statement about HDD moving parts is true?

A. Nothing moves inside an HDD

B. The platters spin and the heads move across them ✓

Spinning platters and moving heads are what make an HDD slower and easier to damage than flash storage.

Match the Pairs

HDD → Hard disk drive: a magnetic storage device with spinning platters and moving read/write heads

platter → A spinning magnetic disc inside an HDD where the data is stored

An HDD has moving parts, so it is slower and more fragile than flash storage → HDD: platters spin + heads move

An HDD gives large capacity at low cost, so it suits desktops, laptops and servers → HDD: 4 TB at low cost per GB

An HDD has no moving parts, so it is faster than flash. → An HDD does have moving parts (spinning platters and moving read/write heads). This makes it slower and more fragile than flash, not faster.

An HDD stores data using light from a laser on pits and lands. → This describes optical storage. An HDD stores data magnetically on its platters.

Key Term

HDD

Hard disk drive: a magnetic storage device with spinning platters and moving read/write heads. It gives large capacity at low cost, but is slower and more fragile than flash.

Fill in the Blanks

1. An HDD stores data on spinning platters.

Hint: Type the name for the spinning disks inside a hard disk drive.

2. The read/write head moves over the platter.

Hint: Type the part that moves across the platter to read and write data.

3. An HDD is a magnetic storage device.

Hint: Type the technology type an HDD uses to store data.

4. An HDD has moving parts, so it is fragile.

Hint: Type the word describing the parts that make an HDD more fragile than flash.

5. HDDs give large capacity at low cost.

Hint: Type the word describing the price of HDD storage per gigabyte.

Spot the Error

Question 1

A drive = "HDD"

B storage = "magnetic"

C moving_parts = False

D print(drive, storage)

Line C — An HDD has moving parts: spinning platters and moving read/write heads. The line should be moving_parts = True.

Question 2

A class HDD:

B storage = "magnetic"

C platters = "spinning"

D heads = "fixed"

Line D — The read/write heads of an HDD move across the platters. They are not fixed. It should be heads = "moving".

Question 3

A capacity = "large"

B cost = "high"

C print("HDD", capacity, cost)

Line B — HDDs give large capacity at low cost. The line should be cost = "low".

Question 4

A hdd_speed = 100

B ssd_speed = 500

C if hdd_speed > ssd_speed:

D print("HDD is slower")

Line C — An HDD is slower than flash (SSD) storage, so its speed is less than the SSD's. The condition should use <, not >.

Question 5

A dropped = True

B if dropped:

C risk = "low"

D print("HDD risk:", risk)

Line C — An HDD is fragile because of its moving parts. If it is dropped, the risk of damage is high, so it should be risk = "high".

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