What are some best practices or tips for optimizing the size and performance of CAB installation files?

1 Benefits of CAB files

CAB files offer several advantages for software developers and users. They can reduce the download size and disk space of software packages, as well as improve the installation speed and reliability. CAB files can also support digital signatures, encryption, and localization features. Additionally, CAB files can be extracted or installed by various tools, such as Windows Installer, Setup API, or third-party utilities.

2 Structure of CAB files

A CAB file consists of four main components: a header, a folder, a file, and a data block. The header contains the metadata of the archive, such as the version, the number of folders and files, and the compression method. The folder contains the information about how the files are grouped and compressed. The file contains the details of each file in the archive, such as the name, the size, the attributes, and the checksum. The data block contains the actual compressed data of the files.

3 Compression methods

CAB files can use different compression methods to reduce the size of the data. The most common ones are MSZIP, LZX, and Quantum. MSZIP is a simple and fast method that uses the deflate algorithm. LZX is a more advanced and efficient method that uses a sliding window and a Huffman tree. Quantum is a proprietary method that uses a modified Lempel-Ziv algorithm. The compression method can be specified for each folder in the CAB file, depending on the type and size of the files.

4 Optimization tips

To optimize the size and performance of CAB files, there are some tips to keep in mind. Choose the best compression method for each folder, such as MSZIP for small or text-based files, LZX for large or binary files, and Quantum for very large or mixed files. Grouping similar files together can also improve the compression ratio and the extraction speed. Splitting CAB files into multiple volumes should be avoided as this can increase the overhead and complexity of the installation process. However, if you must split CAB files, use a tool that supports seamless spanning like Makecab.exe or Cabarc.exe. Lastly, it is important to test and verify your CAB files before distributing them with tools such as Cabview.exe or Expand.exe to avoid errors and issues during installation.