Data Capacity & Calculating Capacity Requirements
What is data capacity?
- Data capacity is the maximum amount of information that a storage device can hold
- If you know the capacity of a storage device, you can calculate how much of different data types can be stored
- Examples of data that could be stored include text, images and sound files
How do you calculate capacity requirements?
- To calculate capacity requirements you need to:
- Know the capacity of the storage device
- Calculate the size of a file (formula)
- Ensure the same units of data storage are used for capacity and size of the file, else convert between units to get them to be the same
- Divide the capacity by size of the file being stored
- The image above shows common capacities of storage devices such as hard drives (HDD), USB flash drives, solid state drives (SSD) and optical disks (CD)
Calculating file sizes
Text Files | ||||||||||||
(Bytes per character) x (Number of characters) | ||||||||||||
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Image Files | ||||||||||||
(Resolution) x (Colour Depth) | ||||||||||||
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Sound Files | |||||||||||||||
(Sample Rate) x (Duration in seconds) x (Bit Depth) | |||||||||||||||
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Worked example
Lyla is a social media influencer. She creates images to be shared on her social media accounts.
Each image has a fixed size of 3 MB. She is storing the images on a USB flash drive which has a capacity of 6 GB.
Calculate how many images can be saved on the storage device. Show your working [2]
How to answer this question:
- Convert 6 GB to MB
- Divide the capacity in MB by the files size in MB
Answer
- 6 GB = 6 * 1000 = 6000 MB
- 6000 / 3 = 2000 images