IaaS, PaaS, SaaS and XaaS — what is the difference?

Cloud computing offers remote access to computing through the Internet. The cloud is based on multiple servers that function like a single machine. These servers are divided into digital machines (Virtual Machines, VMs). Just like an actual server, they have a processor, RAM, storage, etc. But the configuration of a VM within the cloud isn't always limited. For example, you could change RAM volume at any time or lessen the processor cores used. This is viable because the VM uses numerous "actual" (physical) servers simultaneously.

Clouds are used for several applications: databases, web-hosting, online stores, data hosting & sharing, enterprise resource planning systems. To sum it up, the cloud is a digital IT infrastructure that consists of hardware (IaaS) and software (PaaS, SaaS) parts. The company-owner of the infrastructure (or supplier of cloud solution) lends it to any corporation to set up its structures.
Why do businesses choose cloud solutions? Some of the reasons are: availability through the Internet; no need for in-house administrators; constant & timely updates; scalability; comprehensive technical support.

What is IaaS? (Infrastructure as a Service)

IaaS (Infrastructure-as-a-Service) is a model that includes: server foundation, interchanges, capacity, and so on. Rather than maintaining your personal IT framework, you pay for the cloud, and the provider manages the upkeep.

The advantages of IaaS: financial savings through moving infrastructure expenses to the supplier; the information is safe on the physical and software levels on the provider's side; easy scaling.
All applications and IT tools are employed through IaaS: ERP structures, terminals, servers, databases. The IaaS supplier gives fewer options than in other cloud service models. If you need an inconventional IT solution, this version will offer the best freedom for its implementation.
Administration of the IaaS machine is carried out through digital interface. Here, you control the IaaS configuration, upload software, and connect extra systems.

If the task requires extra resources, simply add them to the control panel. If an organization does not require the entirety of the cloud solution, it is easy to reduce resources and cut costs. In addition, infrastructure upkeep and support are on the side of the service supplier. You no longer need to rent a room for a physical server, pay for energy, cooling etc. Thus, renting IaaS allows you to save much more money and time.

When selecting a cloud solution for business, answer the following questions: How is cloud resiliency provided? How does the supplier protect information? Are it's data centers rated Tier III or higher? What ensures the supplier will follow the Service Level Agreement? Is tech support available 24/7? What extra XaaS solutions does the company offer? The "X" within the abbreviation denotes a variable; it may be anything. Regularly these are additions to the IaaS cloud. For instance, BaaS (“Backup-as-a-Service”), an inner automatic backup solution.
The meanings of the XaaS abbreviations vary depending on the company and the context. For instance, "MaaS" can imply "Mobility-as-a-Service" or "Malware-as-a-Service."
PaaS removes the need to address tasks that the supplier has already decided.

What is PaaS? (Platform as a Service)

PaaS (Platform-as-a-Service) is a service version, where the supplier gives a platform for installing programs with predefined settings. It can be a mail server, a database control system, a backup server etc. Benefits of PaaS are: the supplier manages updates, patches and protection of the software; advanced development and testing infrastructure.

PaaS is just like IaaS in lots of ways. However, PaaS clients can not scale the infrastructure. For example, you can not turn off unused capacities.

An essential plus of the PaaS is a standardized toolkit for developers. For example, this may significantly facilitate teamwork on one project.

Examples of PaaS are: Google App Engine, VMWare Cloud Foundry, IBM Bluemix etc.
PaaS offers much less freedom than IaaS, however it additionally thins the range of responsibilities. The preference between IaaS and PaaS is an issue of whether or not these solutions answer the needs of the business.

What is SaaS? (Software as a Service)

SaaS (Software-as-a-Service) — implies the use of programs installed on the supplier's platform. The clients of the SaaS solutions are frequently end-users, for example, social networks, online cinemas, messengers etc.

Corporate clients of SaaS use video conferencing programs, ERP and CRM systems, automation systems etc. Many examples of SaaS solutions are well-known: Gmail, Jira, Bitrix, WordPress, Citrix, etc.

SaaS is an easy choice if the supplier offers the product that solves your tasks because all you need is to adopt a ready-made solution. If you want something special that requires additional development, SaaS will not fit you.

So, which service model to choose in the end?

IaaS is an answer for deploying structures and programs from scratch. Startups and corporations regularly choose IaaS due to the fairly low price and the grand potential for scaling .
PaaS offers cloud assets and a number of development tools. A pre-configured platform is a handy answer if an organization desires to resolve a particular issue and the supplier has all of the essential tools.

Finally, SaaS is a complete product. Both instant messengers and CRM systems are supplied as a part of the SaaS.

The cloud is the base of those models, and their distinction lies in the software program accessories. The preference of model depends on how those accessories resolve the organization's tasks. If the supplier has already solved your problem, pick SaaS. If the supplier does not have a ready-made answer but has the tools, it's far worth using PaaS. If an organization requires computing power to install its personal solutions, IaaS is a great choice.