File Compression (Grade 10 NSC Matric Computer Application Technology): Revision Notes
File Compression
What is file compression?
File compression is a useful technique that allows you to reduce the size of files and folders on your computer. When you compress files, they are often called archived or zipped files. Think of it like packing your clothes into a suitcase - you're taking many separate items and squashing them together into one container that takes up less space.
The compressed files contain many separate files bundled together in one large archive. This process significantly reduces the amount of storage space needed compared to keeping the original files separate. The most common type of compressed file you'll encounter uses the .zip file extension.
Decompressing (also called extracting or unzipping) is the opposite process. When you decompress a file, you're expanding the archived folder back to its original form, like unpacking your suitcase and laying out all your clothes again.
The great news is that Windows can handle .zip files without needing to install any extra programmes or applications, making file compression very accessible for everyday use.
Compressing files and folders
How to compress files and folders in Windows
When you want to compress files or folders using Microsoft Windows, the process is straightforward and built right into the operating system. Understanding these steps will help you efficiently manage your file storage needs.
Worked Example: Compressing Files in Windows
- Open the Start menu and navigate to This PC to access your files
- Select the files and folders you want to include in your compressed archive by holding down the Ctrl key whilst clicking on each item
- Right-click on the selected items and look for the drop-down menu that appears
- Choose "Send To" from the menu options, then select the "Compressed (zipped) folder" option. This creates a zipped file in the same location where your original files are stored
- Enter a name for your compressed folder when prompted
The system will create a new .zip file with the same name as the first file you selected during compression. However, if you're compressing multiple files and folders, it's a good idea to give your archive a descriptive name so you can easily identify its contents later.
How to decompress files and folders
To decompress or extract files from a zipped folder, the reverse process is equally simple and requires no additional software on Windows systems.
Worked Example: Extracting Files from a Zip Archive
- Open the Start menu and navigate to This PC
- Locate the .zip file you want to decompress and right-click on it
- Choose "Extract Files..." from the context menu that appears
- Select "New Folder" when the dialogue box opens, then choose where you want the extracted files to be saved
- Name the destination folder appropriately
- Click "OK" and the files will be extracted to the folder you created
When you zip or unzip files and folders, the original files are never deleted automatically. If you need to remove the originals to save space, you'll need to delete them manually after confirming the compression or extraction was successful.
Advantages of file compression
File compression offers several important benefits that make it valuable for both students and professionals in various scenarios.
Reduced storage space requirements: Compressed files take up significantly less room on your storage devices. This means you can fit more files onto USB drives, hard drives, or cloud storage accounts, making better use of your available space.
Faster file transfers: Because compressed files are smaller, they can be transferred much more quickly between different storage devices. This is particularly helpful when you need to move files over the internet or copy large amounts of data to portable storage devices.
Easier file organisation: When you have many related files, compressing them into a single archive makes it much easier to transfer all the data at once. You can be confident that the recipient will receive all the necessary files without missing any important components.
Email attachment convenience: Many email systems have file size limits for attachments. Compressing large files can help you stay within these limits and successfully send your documents.
Disadvantages of file compression
However, file compression isn't perfect and does come with some limitations that users should be aware of before relying heavily on this technique.
Software dependency: While Windows 10 can handle .zip files natively, some compressed files may require specific software to decompress them properly. This could be problematic if you're trying to access files on a computer that doesn't have the necessary programmes installed.
Time investment: The process of compressing and decompressing files takes time, especially when dealing with large files or high levels of compression. Depending on your computer's processing power and the size of the files involved, this could be a significant factor to consider.
Processing overhead: Your computer needs to work harder to compress and decompress files, which uses system resources and may slow down other tasks temporarily.
Consider the trade-off between storage space savings and the time required for compression/decompression, especially when working with very large files or when you need immediate access to your data.
Practical considerations
Email attachments and file size limits
A common scenario where file compression becomes essential involves email attachments and their size restrictions. Understanding these limitations can save you time and frustration when sharing files.
Many email services have strict file size limits - often around 25MB. When you try to send a file larger than this limit, the email system may automatically suggest using a cloud storage service like Google Drive instead.
However, if you need to send the actual file rather than a cloud link, compressing it first might reduce the size enough to meet the email requirements. This approach gives both you and the recipient more control over the file and doesn't require them to have access to your cloud storage account.
After sending a compressed file to someone, the recipient will need to extract it on their end to access the original content. Make sure to let them know if they need any specific software to open the compressed file, though .zip files should work on most modern computers.
Remember!
Key Points to Remember:
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File compression reduces storage space by bundling multiple files into a smaller archive, commonly using the .zip format
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Windows handles .zip files natively, so you don't need extra software for basic compression and decompression tasks
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Right-click menus provide easy access to compression options - look for "Send To" > "Compressed (zipped) folder"
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Compression is ideal for email attachments and transferring multiple files, but remember it takes time and processing power
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Original files aren't deleted automatically during compression or extraction - you must manually remove them if you want to save space