What is file compression,  How is it done and why is it important ? image

What is file compression, How is it done and why is it important ?

27 Feb, 2024

What is File Compression?

File compression is a method used in computer systems to reduce the size of files. This process reduces the size of the file, allowing it to take up less disk space and use less bandwidth during file transfer and storage. This method offers significant advantages in file storage, transfer and backup processes. Smallr file sizes allow files to be moved and shared faster. However, compression can take time and processing power, which can sometimes impact performance.

The Importance of File Compression:
File compression technology is extremely important in the computer world. It saves time and reduces costs in many ways. It is of great importance in file sharing and backup operations on the Internet because it enables faster and more efficient data transfer.

Basic Concepts of File Compression:

File compression is a technique used on computers and servers to reduce the size of files. Here are the basic concepts you need to know to understand file compression technology.

  1. Compression: File compression reduces the original size of the file by identifying repetitive patterns or redundant information in the data content, thus taking up less storage space.
  2. Lossless and Lossy Compression: File compression compresses the file without changing its data and allows the file to be fully restored to its original state. Lossy compression, on the other hand, compresses the file by permanently removing some information from the file, making it impossible to fully restore the file to its original state.
  3. Compression Algorithms: Compression algorithms are software algorithms used to compress files. These algorithms are used to identify patterns in the data content and to represent the file in its original or near-original form with less information.
  4.  Compression Formats: Compressed files have specific formats. ZIP, RAR, gzip are popular ones.

These basic concepts are important for understanding file compression technology and provide a basic framework for understanding how file compression operations take place.

File Compression Techniques:

  • Lossless Compression: Compresses a file without changing its data. This technique ensures that the file can be fully restored to its original state. Compression formats such as ZIP, gzip and RAR use lossless compression methods
  • Lossy Compression: It reduces the size of a file on disk by permanently removing some information from the data content of the file. This technique is often used for large data files such as audio and image files. File formats such as MP3, JPEG and MPEG use lossy compression methods.

What is Lossy and Lossless Compression, What are the Differences, Why is Lossy Compression Used?
Lossy and lossless compression are the two main compression methods used to reduce the size of files.  What are these methods and why is lossy compression used?

Lossless Compression: Compression without changing the data content of the file. Once the file is compressed, it can return to its original state.


You will not lose any data when the file is compressed.

Lossy Compression: This occurs when some information is permanently removed from the data content of the file. Therefore, it may not be possible to fully restore the file to its original state after compression. But usually the differences are not noticeable to the eye.


Data loss may occur when the file is compressed.

Compression may be irreversible, i.e. it may not be possible to fully restore the original file.

Why Use Lossy Compression? 

Lossy compression is widely used, especially in situations where reducing file size is critical. For example:

Multimedia Files: Audio and video files often have large sizes. While lossy compression can significantly reduce the size of such files, it is often ensured that human perception does not notice the loss of quality as a result of compression.

Data Transfer over the Internet:  Lossy compression speeds up data transfer over the Internet by reducing file size.

Lossy compression is very effective at reducing file size, but should be carefully incorporated into the use case as it carries the risk of data loss.

How does File Compression work?

  • Identification of Data Repetitions: File compression starts by identifying repeating patterns or data structures in the file content.
  • Encoding Repetitive Data: Compression algorithms use various encoding methods to represent repetitive data with a smaller amount of information. These coding methods reorganize the data to take up less space.
  • Data Compression: The encoded data is then processed by a compression algorithm and compressed by removing unnecessary information or representing it with a smaller amount of information. Compression algorithms use different methods depending on the characteristics of the data content.
  • Creating the Compressed File: After the compression process is complete, a file is created in compressed format. This file is a smaller version of the original file.

Basic compression algorithms: LZ77, Huffman, Deflate, etc.
Basic compression algorithms are the logical process used to reduce the size of files. Here are some basic compression algorithms:

  • LZ77 (Lempel-Ziv 1977): It is one of a number of algorithms used for data compression. This algorithm is highly effective for text and data compression. LZ77 looks for data in a window and recursively encodes the patterns it has already seen.
  • Huffman Coding: This algorithm analyzes the probability distribution of the data to be compressed and assigns a code to each symbol. Frequently used symbols have shorter codes, while less frequently used symbols have longer codes. Thus, it performs compression.
  • Deflate Algorithm: Deflate is a compression algorithm that combines LZ77 and Huffman coding. First, the data is compressed with the LZ77 algorithm and then Huffman coding is applied for further compression. The Deflate algorithm is usually used in ZIP format.
  • LZW (Lempel-Ziv-Welch): The algorithm is generally based on the LZ78 algorithm developed by Abraham Lempel and Jacob Ziv in 1978. It is a method for reducing the size of Tag Image File Format (TIFF) or Graphics Interchange Format (GIF) files. It is a table-based lookup algorithm to remove duplicate data and compress the original file into a smaller file. LZW compression is also suitable for compressing text and PDF files. Translated with DeepL.com (free version)

These algorithms represent different techniques used to reduce file size. Each algorithm has advantages and disadvantages and can often be more advantageous to use for certain types of data. Combining or applying these algorithms can improve the overall effectiveness of file compression.

Can data lost during the compression process be recovered?

Compression where you experience data loss usually occurs with lossy compression algorithms. Lossy compression involves the permanent removal of certain information from the data content to reduce the size of the file. Therefore, data lost during the compression process cannot be recovered.

In lossless compression algorithms, the data content of the file is compressed without changing it. In this case, you can reverse the compression process and recover the entire original file.

However, lossy compression methods usually provide stronger compression and focus on achieving smaller file sizes. For example, the JPEG format is a compressed format and is often used for photos. However, during this compression process, some image details can be lost, often too much for a human to notice. For applications where data integrity is important, irreversible lossy compression is not recommended.

In summary, data lost during lossy compression is usually unrecoverable. Therefore, the importance of file content and data integrity should be considered when choosing file compression.

File Compression Programs:

File compression programs are software applications designed to reduce the size of files by using various compression algorithms. These programs are commonly used to save disk space, expedite file transfers, and organize data efficiently. 

  • WinRAR: WinRAR is a free and popular file compression program for Windows users. It supports a wide range of compression formats, including RAR, ZIP and more. WinRAR offers high compression rates and includes features such as file splitting. It also allows you to put a password on your file.
  • 7-Zip: 7-Zip is a free and open-source file archiver that supports various compression formats, including its proprietary 7z format, ZIP and TAR. It provides powerful compression.
  • WinZip: WinZip is one of the oldest and best known file compression tools. It offers a user-friendly interface and supports various compression formats such as ZIP, RAR and 7z. In addition to file encryption, WinZip includes features such as cloud integration.
  • PeaZip: It is a free, open source file archiver that supports multiple formats, including its own Pea format, ZIP and TAR. It offers encryption and has a simple, easy-to-use interface.
  • StuffIt: StuffIt is a cross-platform file compression utility available for both Windows and macOS. It supports various compression formats and provides features such as file encryption and cloud backup integration.
  •  Bandizip: It is a lightweight, fast file compression tool for Windows. It supports a wide range of formats including ZIP, RAR, 7z and more. Bandizip offers high-speed compression and extraction features.

These file compression programs offer different features and algorithms according to your needs. Users can choose the one that best suits their needs depending on the compression ratio and user interface, encryption, cloud sharing, cross-platform (macOS, Windows), etc.

In summary, file compression is an excellent technology for reducing file sizes on computer systems. This process provides great benefits when storing, transferring and backing up files.

  • is File Compression? File compression is a process used to reduce file sizes on computer systems.
  • Importance of File Compression: File compression reduces storage costs, speeds up data transfer, and facilitates file sharing on the Internet.
  • Basic Concepts of File Compression: Basic concepts such as lossy and lossless compression, compression algorithms, compression formats provide an understanding of the file compression process.
  • Compression Techniques: Lossless and lossy compression techniques and different compression algorithms are used in file compression.


  • Remember that file compression techniques are an important part of your data management strategies. Using compression for data storage, transfer and backup can save you time and reduce costs.
  • Understand Compression Methods Thoroughly: Carefully evaluate the differences between lossy and lossless compression methods and the advantages and disadvantages of each. It is very important to choose the most appropriate compression method depending on the file type and your needs.
  • Pay Attention to Data Security: Consider data security during the file compression process. Develop backup strategies to prevent data loss, take precautions and regularly check the results of compression operations.