← IGCSE Computer Science Paper 1

File compression utility

Utility software that makes files smaller to save storage space and send them faster, and can restore (unzip) them to their original form when needed.

Part of: IGCSE Computer Science 0478 — 4.1 Types of Software and Interrupts — Module 14

Understanding File compression utility in IGCSE Computer Science Paper 1

What it does: A smaller file means less data to transfer, so zipping before emailing makes the transfer faster. Several files are compressed into one smaller archive, so less storage space is used. Compression utilities help manage and maintain files and the computer, so they are utility software, which is system software. Unzipping (decompressing) restores the files so you can open and use them again. The utility can restore the file to its original form, but the student must unzip it before opening it.

Common mistakes: A compressed file should be smaller than the original (50), so 80 is wrong. Compression makes files smaller, so the size should be less than 50, for example 20. The IF statement is missing THEN. It should be IF storageFull = TRUE THEN, so the video is compressed to free up storage space when storage is full.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

🖨 Print worksheet + answer key Add File compression utility to a class →

This module's key terms are also in a printable crossword (Modules 356–372) and word search (Modules 356–389).

Take this worksheet further — free with Cloodit

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

Learning
Duo
What is the main job of a file compression utility?
It makes files smaller so they use less storage spaceIt makes files bigger so they are easier to find
Matches
Zip a file, then open it without unzipping it first
↓
A compressed file must be unzipped (restored) with the compression utility before it can be used normally
Applying
Meanings
Term
compression utility
Meaning
Utility software that makes files smaller to save storage space and send them faster, and can restore (unzip) them to their original form when needed.
Practice
FileSize ← 500
Testing
Gaps
bigFile TO smallFile
Check Answer
Spots
2zipped ← compress(photo)
3zippedSize ← 80

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

The 'Parrotfish' badge — Function Builder, one of Cloodit's 106 collectible badges
Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy
Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games
Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print
Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Add to class →

Quick Questions

1. What is the main job of a file compression utility?
A. It makes files smaller so they use less storage space ✓
B. It makes files bigger so they are easier to find
A compression utility reduces file size, saving storage space. It does not make files bigger.
2. Which type of software is a file compression utility?
A. Utility software (a type of system software) ✓
B. Application software such as a word processor
Compression utilities help manage and maintain files and the computer, so they are utility software, which is system software.
3. You zip a folder of photos before emailing it to a friend. Why does this help?
A. The photos are automatically printed
B. The smaller file can be sent faster ✓
Smaller files take less time to transfer over a network or the internet.
4. What does 'unzipping' a compressed file do?
A. It restores the file to its original form so it can be used ✓
B. It permanently deletes the file from the computer
Unzipping (decompressing) restores the files so you can open and use them again.
5. A student's USB drive is almost full. Which utility could help them fit more files on it?
A. A firewall
B. A file compression utility ✓
Compressing files makes them smaller so more fit in the same storage space. A firewall controls network traffic and does not save space.

Match the Pairs

zip report.docx → Compresses a file into a smaller zip archive so it uses less storage space
unzip photos.zip → Restores the compressed files to their original form so they can be used again
A compression utility reduces file size so a file can be sent faster over a network → zip holiday_video.zip video.mp4 -> email
Compression saves storage space by making many files take up less room on a disk → zip archive.zip file1.txt file2.txt file3.txt
Zip a file, then open it without unzipping it first → A compressed file must be unzipped (restored) with the compression utility before it can be used normally
Zipping makes a file bigger but faster to send → Compression makes a file smaller, not bigger; the smaller size is what makes it faster to send

Key Term

compression utility
Utility software that makes files smaller to save storage space and send them faster, and can restore (unzip) them to their original form when needed.

Fill in the Blanks

1. COMPRESS bigFile TO smallFile
Hint: Type the command that makes a file smaller so it uses less storage space.
2. UNZIP archive TO originalFile
Hint: Type the keyword that shows where the restored file is sent.
3. IF compressedSize < originalSize THEN OUTPUT "Space saved" ENDIF
Hint: Type the comparison operator that checks the compressed file is smaller than the original.
4. compressed ← COMPRESS(photo) SEND(compressed)
Hint: Type the variable holding the smaller file so it transfers faster.
5. UNZIP(archiveZip)
Hint: Type the command that restores a zipped file to its original form.

Spot the Error

Question 1
A originalSize ← 50
B zipped ← compress(photo)
C zippedSize ← 80
D saved ← originalSize - zippedSize
Line C — A compressed file should be smaller than the original (50), so 80 is wrong. Compression makes files smaller, so the size should be less than 50, for example 20.
Question 2
A IF storageFull = TRUE
B compress(videoFile)
C ENDIF
Line A — The IF statement is missing THEN. It should be IF storageFull = TRUE THEN, so the video is compressed to free up storage space when storage is full.
Question 3
A archive ← "photos.zip"
B files ← compress(archive)
C OUTPUT files
Line B — To restore the files from a zip archive you need to unzip it, not compress it again. The line should be files ← unzip(archive).
Question 4
A FOR i ← 1 TO 3
B compress(file[i])
C ENDIF
Line C — A FOR loop is closed with NEXT i, not ENDIF. ENDIF is used to close an IF statement.
Question 5
A fileSize ← 100
B sendTime ← fileSize * speed
C compressedSize ← 40
D newTime ← compressedSize / speed
Line B — Time to send a file is the size divided by the speed, so it should be fileSize / speed. A smaller compressed file therefore sends faster.

Student with a class code? Join your class →