lzma vs xz: What are the differences?

Introduction: 
LZMA and XZ are both compression formats that offer high compression ratios and are widely used in software applications and data archiving.

1. **Compression Algorithm**: The key difference between LZMA and XZ is the compression algorithm they use. LZMA uses the Lempel-Ziv-Markov chain algorithm, while XZ implements the LZMA2 algorithm, which is an improved and optimized version of LZMA. This enhancement in the algorithm used by XZ results in better compression performance compared to LZMA.

2. **Container Format**: Another significant difference is the container format used by LZMA and XZ. LZMA does not have a specified container format and is typically wrapped in other formats like 7z or .lzma. On the other hand, XZ has its container format called .xz, which provides a standard way of storing compressed data. This makes XZ more self-contained and easier to use in various software applications.

3. **Multithreading Support**: XZ offers native multithreading support during both compression and decompression processes, allowing for faster processing on multi-core systems. In contrast, LZMA does not have built-in support for multithreading, which can result in slower compression and decompression speeds on modern hardware.

4. **Memory Usage**: XZ generally consumes more memory during the compression and decompression processes compared to LZMA. This higher memory usage can be a consideration when working with limited resources or when memory efficiency is crucial for specific applications.

5. **Compatibility**: LZMA has been around for a longer time and has broader compatibility with various operating systems and software applications. XZ, being a more recent standard, may have limited support in certain older systems or applications that have not yet adopted the XZ format.

6. **Compression Speed**: In terms of compression speed, LZMA tends to be faster than XZ when compressing data. This difference in speed can be a factor to consider when choosing between the two formats based on the specific requirements of a compression task.

In Summary, LZMA and XZ differ in their compression algorithms, container formats, support for multithreading, memory usage, compatibility, and compression speed.