IaaS resources primarily comprise of three main resources – servers and storage (where data and information is held), networking firewalls / security (put in place to protect the data and information) & data centres/buildings (physical buildings where data servers are stored).
This differs from PaaS which typically comprises of these three as well as operating systems and software/development tools (what tools the platforms offers, such as analytics or others USPs). SaaS offers all of these as well as hosted applications.
