← IGCSE Computer Science Paper 1

Magnetic storage: platters, tracks and sectors

A spinning circular disk in magnetic storage. Its surface is split into tracks (concentric circles) and sectors (sections of a track), where data is stored as magnetised areas.

Part of: IGCSE Computer Science 0478 — 3.3 Data Storage — Module 9

Understanding Magnetic storage: platters, tracks and sectors in IGCSE Computer Science Paper 1

What it does: Each track is split into sectors, which are small sections that hold the data. Magnetic storage records binary by magnetising tiny areas of the platter surface in different directions. Tracks are concentric circles, like rings, that run around the platter. The platter spins, so the track and sector pass under the read/write head.

Common mistakes: Tracks are concentric circles on the platter, not straight lines. It should be tracks = "concentric circles". Each track is split into sectors, so the total number of sectors is tracks multiplied by sectors per track. It should use * instead of +.

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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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Each concept is reinforced from every angle — learned, then applied, then tested.

Learning

Duo

What is a platter in magnetic storage?

A spinning circular disk that stores dataA small chip with no moving parts

Matches

A track is a section cut across a platter like a slice of pizza.

↓

This describes a sector, not a track. A track is a concentric circle, and a sector is a section of a track.

Applying

Meanings

Term

platter

Meaning

A spinning circular disk in magnetic storage. Its surface is split into tracks (concentric circles) and sectors (sections of a track), where data is stored as magnetised areas.

Practice

platter = spinning circular disk

Testing

Gaps

= spinning circular disk

Check Answer

Spots

1platter = "spinning disk"

2tracks = "straight lines"

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Quick Questions

1. What is a platter in magnetic storage?

A. A spinning circular disk that stores data ✓

B. A small chip with no moving parts

A platter is the circular disk that spins inside a magnetic storage device. Data is stored on its surface.

2. What shape are the tracks on a platter?

A. Concentric circles ✓

B. Straight lines across the disk

Tracks are concentric circles, like rings, that run around the platter.

3. What is a sector?

A. A section of a track ✓

B. A whole platter

Each track is split into sectors. A sector is one small section of a track.

4. How is data stored on the surface of a platter?

A. As tiny pits and lands burned by a laser

B. As magnetised areas ✓

Magnetic storage records data as areas of magnetisation on the surface. Pits and lands are used by optical storage.

5. Which statement about a platter is correct?

A. It stays still while the data moves past it

B. It spins while data is read or written ✓

The platter spins, so the track and sector pass under the read/write head.

Match the Pairs

platter → A spinning circular disk in a magnetic storage device that has a surface coated with magnetic material to hold data

track → One of the concentric circles on a platter surface, like the rings of a target, that data is stored along

A sector is a small section of a track. It is the smallest block of data that is stored on the platter. → sector

Data on a platter is stored as tiny magnetised areas, which are magnetised one way or the other to show 1s and 0s. → magnetised area

A track is a section cut across a platter like a slice of pizza. → This describes a sector, not a track. A track is a concentric circle, and a sector is a section of a track.

A platter is a fixed, flat disk that never moves while data is read. → A platter spins while data is read or written. It does not stay still.

Key Term

platter

A spinning circular disk in magnetic storage. Its surface is split into tracks (concentric circles) and sectors (sections of a track), where data is stored as magnetised areas.

Fill in the Blanks

1. platter = spinning circular disk

Hint: Type the name of the spinning circular disk in magnetic storage.

2. tracks = concentric circles on a platter

Hint: Type the shape that the tracks form on the platter.

3. sectors = sections of a track

Hint: Type the term for the sections a track is divided into.

4. data = magnetised areas on the platter

Hint: Type the word describing how data is held on the surface.

5. platter CONTAINS tracks track CONTAINS sectors

Hint: Type the part that each track is split into.

Spot the Error

Question 1

A platter = "spinning disk"

B tracks = "straight lines"

C sectors = "sections of a track"

Line B — Tracks are concentric circles on the platter, not straight lines. It should be tracks = "concentric circles".

Question 2

A tracks = 4

B sectors = 8

C spinning = True

D total = tracks + sectors

Line D — Each track is split into sectors, so the total number of sectors is tracks multiplied by sectors per track. It should use * instead of +.

Question 3

A class Platter:

B shape = "square"

C spins = True

Line B — A platter is a circular disk, not a square. It should be shape = "disk".

Question 4

A def read(track, sector):

B head.move_to(sector)

C return head.read(sector)

Line B — The read/write head must first move to the correct track. It should be head.move_to(track).

Question 5

A for sector in platter:

B for sector in track:

C read(sector)

Line A — A platter is divided into tracks first, and each track is divided into sectors. The outer loop should be for track in platter:.

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