Learn in the textbookCloud Service Models (○aaS)
DefinitionPaaS (Platform as a Service) is a model in which a provider offers, over the network, the platform (基盤) for building and running applications.
ExplanationThe platform includes the OS and middleware (ミドルウェア), software such as a database management system that works between the OS and applications, and the provider also supplies the servers they run on. Users build and run their own applications on top, leaving maintenance and updates of the platform to the provider.
AnalogyIt is like renting a kitchen already fitted with cookware and a stove, then cooking from your own recipes.
Memory hookP stands for Platform, the same word as a railway platform. The railway company builds the platform, while the trains that leave from it (the apps) are the user's own.