Lesson Outcomes
By the end of this worksheet, you should be able to:
- Identify common types of secondary storage devices (HDDHard Disk Drive: Magnetic storage with spinning platters. High capacity, lower cost, but slower and less durable than SSDs., SSDSolid State Drive: Uses flash memory. Faster, more durable, and lower power than HDDs, but typically more expensive., OpticalUses lasers to read/write data on discs like CDs, DVDs, Blu-ray. Lower capacity and slower than modern drives., Magnetic TapeSequential access storage often used for backups and archives due to high capacity and low cost, but very slow access times.).
- State typical capacities for different storage devices.
- Understand the units of data storage (bitThe smallest unit of data, a 0 or 1., nibble4 bits., byte8 bits., KBKilobyte: Approx. 1000 bytes., MBMegabyte: Approx. 1000 KB., GBGigabyte: Approx. 1000 MB., TBTerabyte: Approx. 1000 GB., PBPetabyte: Approx. 1000 TB.) and their order.
- Calculate storage requirements for given files and determine suitable storage devices.
- Perform binary addition for 8-bit numbers, showing carries.
- Briefly explain how data is represented (numbers, characters, images, sound).
Starter Task (Not Scored)
Quick check! How is text typically represented in computers?
How are individual characters (like 'A', 'b', '$') usually stored?
How many bits are typically in one byte?
Which list shows storage units in order from smallest to largest?
In one sentence, why are character sets necessary?
Computers only understand binary (0s and 1s), so character sets provide a standard way to map each character to a unique binary code.
Introduction: Storing Digital Data
We've learned about the units used to measure data. Now, let's look at the devices that store this data and how much they can typically hold.
We'll explore common storage devices, how to calculate if your files will fit on a device, and the basics of binary addition which computers use for calculations.
Hover over keywordsThis is an example tooltip! for definitions.
Task 1: Storage Device Capacities (Max 5 points)
Different storage devices have vastly different typical capacities. Match the device type to its common capacity range.
Device Pool (Drag these)
~ 700 MB
~ 4.7 GB
16 GB - 256 GB
256 GB - 1 TB
1 TB - 8 TB+
Task 2: Will It Fit? Storage Calculation (Max 3 points)
You need to store the following files:
- Document.docx: 500 KB
- Presentation.pptx: 25 MB
- Holiday Photos (Folder): 4.5 GB
- Software Install: 800 MB
First, calculate the total storage required in GB.
Now, select ALL the devices below that have enough capacity to store all these files:
Task 3: Binary Addition
Computers perform calculations using binary addition. The rules are simple:
- 0 + 0 = 0
- 0 + 1 = 1
- 1 + 0 = 1
- 1 + 1 = 0, carry 1 (to the next left column)
- 1 + 1 + 1 = 1, carry 1 (result of adding 1+1, plus a carry-in of 1)
For practice questions, use the linked spreadsheet:
Open Binary Addition Practice (Excel)Note: This task is for reference and practice via the spreadsheet. It is not automatically scored on this page.
Task 4: Exam Practice Questions
Apply your knowledge to these exam-style questions.
1. List two types of storage device and state a typical capacity for each. [2 marks]
2. A user has 200 photos, each 5MB in size, and 5 videos, each 600MB in size. Calculate the total storage needed in GB. Show your working. [3 marks]
3. Add the following two 8-bit binary numbers: 01101011 + 00110110. Show carries where appropriate. [2 marks]
Key Takeaways
- Storage Devices: Different devices (CDOptical storage, a laser reads and writes the 700MB capacity optical disks. Disks are cheap and portable., DVDOptical storage, a laser reads and writes the 4.7GB capacity optical disks which are cheap and portable, but a bit more expensive than CDs., USB DriveA solid state storage removable storage device which is very portable, comes in capacities from 1GB up to 512GB, SSDNo moving parts means this high capacity, fast, durable, low power and reliable secondary storage device is good for laptops but it's expensive, HDDHigh capacity magnetic secondary storage device. It has spinning platters so it wears out, making it less reliable and portable than SSD.) have vastly different typical capacities.
- Capacity Calculation: To determine if files fit, convert all file sizes to a common unit (e.g., GB) and sum them up. Compare the total to the device capacity (remembering 1 GB ≈ 1000 MB, 1 MB ≈ 1000 KB).
- Binary Addition: Computers use binary addition rules (0+0=0, 0+1=1, 1+1=0 carry 1, 1+1+1=1 carry 1) for all calculations.
- Data Representation:
- Numbers are stored in pure binary.
- Characters use character sets like ASCIIAmerican Standard Code for Information Interchange: A 7-bit character set storing 128 characters, including English letters, numbers, and symbols. or UnicodeA character set that aims to represent characters from all the world's writing systems. Uses more bits than ASCII (e.g., 16 or 32)..
- Images are stored as grids of pixelsPicture Element: The smallest unit of a digital image or display., with colour depthThe number of bits used to represent the colour of a single pixel. determining the number of colours and metadataData about data, such as image dimensions, resolution, colour depth, date created. storing extra info.
- Sound is stored by samplingRecording the amplitude (height) of a sound wave at regular intervals. the analogue wave, with sample rateThe number of samples of audio recorded per second (measured in Hz). and bit depthAlso known as resolution. The number of bits used to store each audio sample. affecting quality and file size.
Task 5: Check Your Knowledge Quiz (Max 5 points)
Data Storage Quiz
Score: 0 / 0
Task 6: Exam Practice Questions
Apply your knowledge to these exam-style questions.
1. List two types of storage device and state a typical capacity for each. [2 marks]
2. A user has 200 photos, each 5MB in size, and 5 videos, each 600MB in size. Calculate the total storage needed in GB. Show your working. [3 marks]
3. Add the following two 8-bit binary numbers: 01101011 + 00110110. Show carries where appropriate. [2 marks]
Extension 1: How Optical Discs Work
Watch the following video clip (from 0:24 to 1:01) which explains the process in more detail.
After watching the clip, briefly explain in your own words how data is read from an optical disc:
Note: This explanation is for your understanding and is not automatically scored.
What's Next?
You've explored data storage devices, capacity calculations, and binary addition!
Next, we'll look at:
- Compression (Lossy & Lossless) (Spec 1.2.5)
- Moving on to Computer Networks, Connections and Protocols (Spec 1.3)
Task 7: Worksheet Progress
Check your score based on the interactive quiz questions and activities.
Your Score: 0 / 0
Note: Score based on Tasks 1, 2 & 5. Starter Task, Binary Addition, Exam practice & Extension activities are not auto-scored.