Research software has been categorized in different contexts to serve different goals. We start with a look at what research software is, before we discuss the purpose of research software categories. We propose a multi-dimensional categorization of research software. We present a template for characterizing such categories. As selected dimensions, we present our proposed role-based, developer-based, and maturity-based categories. Since our work has been inspired by various previous efforts to categorize research software, we discuss them as related works. We characterize all these categories via the previously introduced template, to enable a systematic comparison.

The Research Software Alliance (ReSA) and the Netherlands eScience Center hosted a two-day international workshop in Amsterdam (the Netherlands) on 8-9 November 2023 to set the future agenda for national and international funders to support sustainable research software. As the importance of software in research has become increasingly apparent, so has the urgent need to sustain it. Funders can play a crucial role in this respect by ensuring structural support. Over the past few years, a variety of methods for sustaining research software have been explored, including improving and extending funding policies and instruments. During the workshop, funding organizations joined forces to explore how they can effectively contribute to making research software sustainable. In preparation of the workshop, a draft of a future international declaration, titled "Amsterdam Declaration on Funding Research Software Sustainability" was created by the Research Software Alliance, the Netherlands eScience Center and with input from stakeholders in the field.

A presentation given at the International funders workshop on The Future of Research Software, 8 & 9 November 2022, Amsterdam. In the presentation, I describe what research software is all about, from the perspective of a researcher. The main topic is a classification of research software into several classes: software is a component in our scientific instruments
software
is the instrument
software analyses research data
software presents research results
software is superglue, duct tape and lubricant