Which model requires the customer to perform their own patching of systems?

The answer is IaaS, which stands for Infrastructure as a Service. In this model, users are provided with virtualized computing resources over the internet. They are responsible for managing the operating systems and applications they install on the infrastructure, including performing system patching. This means that while they benefit from the flexibility and scalability of cloud resources, they also take on the responsibility of keeping the systems secure and up to date through their own patch management efforts.

In contrast, SaaS (Software as a Service) typically handles all aspects of application management, including updates and patches, leaving users without the need to worry about these tasks. PaaS (Platform as a Service) provides a platform allowing developers to build, deploy, and manage applications without managing the underlying infrastructure, often including automated updates. DBaaS (Database as a Service) manages database services, where the provider typically takes care of database maintenance, patching, and updates, thus not requiring customers to patch systems themselves.