IB Computer Science HL · Year 2 · Lesson 30

Secondary storage, compression and cloud services

Computer performance emerges from the interaction of processing, memory, storage and specialized hardware.

Paper 150 minutesA1.1.7 · A1.1.8 · A1.1.9
Use Next or the arrow keys.
Course homeIA hub2027 case study
Today’s targets

What you need to be able to do

2 / 8
  • DescribeInternal and external types of secondary memory storage
  • DescribeThe concept of compression
  • DescribeThe different types of services in cloud computing
A1.1.7A1.1.8A1.1.9
Paper 1 lensMatch the depth of every response to the command term. Previously learned content can move quickly, but retrieval must still be accurate.
Page 2 of 8
Retrieve

Rapid Recall Deck

3 / 8

Say the answer aloud before flipping. Mark secure knowledge quickly and spend time on the gaps.

  • How do SSDs and HDDs differ in basic operation?: SSDs use solid-state flash memory with no moving parts; HDDs store data magnetically on spinning platters.
  • What are common examples of internal and external secondary storage?: Internal: SSD, HDD, eMMC. External: SSD, HDD, optical drive, flash drive, memory card, and NAS.
  • What is the difference between lossless and lossy compression?: Lossless compression allows exact reconstruction of the original data; lossy compression permanently removes some information to achieve greater reduction.
  • What kind of data suits run-length encoding (RLE)?: Data containing long repeated runs of the same value, because RLE stores the value and run length instead of each repeated item.
  • What is transform coding in compression?: It converts data into a different representation so it can be compressed more effectively, commonly in image or audio compression.
  • What do SaaS, PaaS, and IaaS provide?: SaaS provides complete applications; PaaS provides a managed development/deployment platform; IaaS provides virtualized computing infrastructure.
  • How does control generally change from SaaS to PaaS to IaaS?: User control and configuration flexibility generally increase toward IaaS, while the provider manages more of the stack in SaaS.
Page 3 of 8
A1.1.7 + A1.1.8 · Learn

Core knowledge and application

4 / 8
A1.1.7Describe

Internal and external types of secondary memory storage

Computer performance emerges from the interaction of processing, memory, storage and specialized hardware.

Exam moveGive a detailed, accurate account of what happens or what something is like.
Required detail 1Internal hard drives: solid state drive (SSD), hard disk drive (HDD), embedded multimedia cards (eMMCs)
Required detail 2External hard drives: SSD, HDD, optical drives, flash drives, memory cards, network attached storage (NAS)
Required detail 3The scenarios in which the various types of drive are used

Explain it without notes

Describe: Internal and external types of secondary memory storage in the context of a school upgrading computers for graphics, coding and machine learning.

  • Internal hard drives: solid state drive (SSD), hard disk drive (HDD), embedded multimedia cards (eMMCs)
  • External hard drives: SSD, HDD, optical drives, flash drives, memory cards, network attached storage (NAS)
  • The scenarios in which the various types of drive are used
A1.1.8Describe

The concept of compression

Computer performance emerges from the interaction of processing, memory, storage and specialized hardware.

Exam moveGive a detailed, accurate account of what happens or what something is like.
Required detail 1Compare lossy compression methods and lossless compression methods
Required detail 2Run-length encoding and transform coding

Explain it without notes

Describe: The concept of compression in the context of a school upgrading computers for graphics, coding and machine learning.

  • Compare lossy compression methods and lossless compression methods
  • Run-length encoding and transform coding
Page 4 of 8
A1.1.9 · Learn

Core knowledge and application

5 / 8
A1.1.9Describe

The different types of services in cloud computing

Computer performance emerges from the interaction of processing, memory, storage and specialized hardware.

Exam moveGive a detailed, accurate account of what happens or what something is like.
Required detail 1Services: software as a service (SaaS), platform as a service (PaaS), infrastructure as a service (IaaS)
Required detail 2Compare the approaches of SaaS, PaaS, and IaaS in various real-world scenarios, recognizing that different degrees of control and flexibility influence resource management and resource availability

Explain it without notes

Describe: The different types of services in cloud computing in the context of a school upgrading computers for graphics, coding and machine learning.

  • Services: software as a service (SaaS), platform as a service (PaaS), infrastructure as a service (IaaS)
  • Compare the approaches of SaaS, PaaS, and IaaS in various real-world scenarios, recognizing that different degrees of control and flexibility influence resource management and resource availability
Page 5 of 8
Apply

Transfer to a new scenario

6 / 8
ScenarioA school upgrading computers for graphics, coding and machine learning needs a design or technical decision related to today’s topic. Explain what matters and why.
  • Internal hard drives: solid state drive (SSD), hard disk drive (HDD), embedded multimedia cards (eMMCs)
  • External hard drives: SSD, HDD, optical drives, flash drives, memory cards, network attached storage (NAS)
  • Compare lossy compression methods and lossless compression methods
  • Run-length encoding and transform coding
  • Services: software as a service (SaaS), platform as a service (PaaS), infrastructure as a service (IaaS)
  • Compare the approaches of SaaS, PaaS, and IaaS in various real-world scenarios, recognizing that different degrees of control and flexibility influence resource management and resource availability
Page 6 of 8
Exam lens

Paper 1 practice

7 / 8
Build the response before checking notesUse precise terminology and match the required depth.
  1. Describe: Internal and external types of secondary memory storage in the context of a school upgrading computers for graphics, coding and machine learning.
  2. Describe: The concept of compression in the context of a school upgrading computers for graphics, coding and machine learning.
  3. Describe: The different types of services in cloud computing in the context of a school upgrading computers for graphics, coding and machine learning.
Self-checkAnswer the exact command term. For explain, include mechanism/reason; for compare, pair criteria; for discuss/evaluate/justify, build supported reasoning and a conclusion.
Page 7 of 8
Homework

Finish the learning cycle

8 / 8

IA — main task

Continue Criterion D development. Keep code readable, record meaningful implementation decisions, and maintain testing/evidence notes as you work.

Syllabus — short

Complete one targeted Paper 2/Paper 1 retrieval task from today’s lesson.

Designed by David Xu
© 2026 David Xu. All rights reserved.
Educators and students are welcome to use these materials for non-commercial teaching and learning with attribution. Please share the original link when possible. Reposting, redistributing modified copies, removing attribution, or commercial use requires prior permission.
End of Lesson 30.