Everything as a Service (abbreviated to XaaS) describes as a generic term the consequence of ultimately referring to “everything” as a service within cloud computing. This includes people, from applications to runtime environments and servers, for whom costs arise mainly from their use.
The 3 most common sub-terms for this are Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS), which are represented hierarchically via the SPI model – with SaaS at the top based on IaaS with PaaS as a mediating layer in between.
XaaS is based on software as a service (SaaS)
SaaS is understood to mean those applications that are provided as a service over the Internet and are used for IT outsourcing . Prominent examples of this are the Office 365 cloud application from Microsoft, the Adobe Creative Cloud and Cisco WebEx Meetings
The customer receives the latest version of the software on the basis of a subscription model and can book additional functions or services, such as larger storage space or a higher number of meetings, for a surcharge. As the software used is up-to-date, the risk of IT vulnerability analysis can be reduced.
Frequent advantages of SaaS, the basis of, are increased flexibility with lower investment risk for the user. However, this is countered by the dependence on the service provider and ISP.
Platform as a Service (PaaS) is also part of the core XaaS
PaaS is understood to be the provision of a runtime or development environment, for which use (on demand) has to be paid for. Well-known representatives for this are Microsoft Azure and the Google App Engine. Microsoft’s Azure serves to provide and scale applications for the user in a network of data centers, distributed all over the world, which is supported by Microsoft. The Google App Engine primarily serves as a platform for developing and hosting web applications.
The advantage for the user with PaaS is that he always has the latest version and does not have to worry about upgrades outside of his applications. A disadvantage can be seen as being bound by the requirements of the cloud provider, for example when using the programming languages that are supported.
In addition to PaaS and SaaS, Infrastructure as a Service (IaaS) also forms the basis of XaaS
IaaS provides for the renting of computer infrastructure instead of the classic purchase of computer infrastructure.
The best-known provider of this business model is Amazon with its Elastic Compute Cloud (EC2) and its Simple Storage Service (S3). S3 is a scalable and cost-effective, high-speed web service designed for online backup and archiving of data and application programs. In times of malware such as Emotet , secure backups for company data are very important.
EC2, in turn, is a web-based service that allows its customers to run application programs on a large number of virtual machines.
Advantages based on IaaS are the interception of load peaks or the freeing up of idle capacities through simple scalability, software testing on many different platforms and making applications affordable through one-time use.