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FSL development

FSL is a collection of MRI processing and analysis tools written in a range of programming languages (C++, BASH, TCL/TK, Python and Javascript to name a few), and published for use on macOS and Linux. FSL has historically been tightly coupled to UNIX-like operating systems, so using it on Windows is via the Windows Subsystem for Linux (or by installing FSL within a virtual machine).

FSL is published and installed using the conda package and environment management system. Each FSL project is built as a conda package, and published to an internally hosted (but publicly available) conda channel.

  • The FSL release history page contains an overview of every version of FSL that has ever been released, starting from version 1.0 in June 2000.
  • The Local development page contains notes on compiling FSL C++ tools on your local system.
  • The Management section contains information on the procedures used by the FSL development team for developing FSL projects, and managing FSL releases.

Older FSL releases

Prior to FSL 6.0.6, FSL was released and installed as a monolithic archive file, containing most FSL tools, and a separate conda environment called fslpython, configured after the archive file was installed.

Some of the reasons for transitioning to a purely conda-based release model were as follows:

  • Simplify FSL installation procedure
  • Reduce the size of ${FSLDIR}
  • Allow "minimal" FSL installations, with only the utilities that are required
  • Improve build reproducibility
  • Improve support for container-based FSL installations
  • Simplify cross-platform management of external dependencies (e.g. VTK, OpenBLAS)