The NAS software policy was developed for the following reasons:

• NAS users have diverse and potentially conflicting software requirements.
• Revalidating code against new software components can be a time-consuming process that may not result in a demonstrable benefit in terms of performance, functionality, or reliability.
• Over time, maintaining an increasing number of software modules can make it difficult for users to find modules that meet their needs, and increases complexity for both users and support staff, as multiple versions will have different bugs and may depend on different versions of other software components.
• Outdated software versions may affect the reliability of code that depends upon the software.

Policy

The following policy applies to software modules installed on NAS systems and to any requests for the installation of new software:

• In general, no more than two versions of each software module are available.
• To provide a stable environment for users, software modules will remain available for at least one year (barring exceptional circumstances). After the first year, only the latest patch of each major/minor version will be retained. (For example, if v3.2.7 has been available for more than a year, and v3.2.9 is also available, v3.2.7 may be deprecated.)
• To request new software, contact NAS User Services. There must be sufficient demand before software is installed; otherwise, users will be expected to install the software themselves.
• Software that has been installed for more than three years and has not been used for more than one year may be deprecated and removed at the discretion of the system administrators.
• Commercial software that is no longer supported by the vendor may be deprecated and removed at the discretion of the system administrators.
• Deprecated software is available for only three months, and access is restricted. If you require access, please contact NAS User Services and provide a justification.
• Software that is no longer functional or presents an unacceptable security risk may be removed at any time and may bypass the deprecation and removal process.

Note: For software packages that contain multiple components, such as Perl and Python, the deprecation and removal process is based solely on the primary package version, without consideration of the additional components. For example, the Python software package includes additional components such as numpy and matplotlib. When a Python version is deprecated, the newer version might not include the same versions of these components.