What is required for a software invention to be patentable?

For a software invention to be patentable, it generally needs to be coupled to hardware, as this demonstrates a specific application or technical effect. This requirement stems from the need to illustrate that the software is not merely an abstract idea or algorithm but rather a tangible invention that produces a practical result when applied alongside hardware.

When software is integrated with hardware, it forms a system that can function in the practical world, thereby meeting the criteria for patentability that focus on utility and application. This coupling can help to satisfy the requirement for a "useful process, machine, manufacture, or composition of matter" as stated in patent laws.

In contrast, while the other options suggest some important aspects of software and its deployment, they do not directly address the fundamental requirement that ties software to patent eligibility. For example, independently functional software may be innovative but lacks the connection needed for patentability without hardware. Software in the public domain cannot be patented due to lack of novelty, and compliance with international standards, while useful for market acceptance and interoperability, does not inherently confer patentability.