Dr. Eliyahu Moshe Goldratt  in his Theory of Constraints  stated that the strength of any chain, process or system is determined by its weakest link. Successful systems identify the constraints and effects, the changes necessary to remove them. Small and medium enterprises that are IT constrained must, therefore, make an effort to change their operative methodologies and harness the cloud to strengthen their business operations. Interestingly, a number of cloud based IT services are emerging to support IT constrained organisations.
Infrastructure as a Service (IaaS) options available in the cloud allow SMBs harness expensive infrastructure at nominal costs to exploit available, in-house IT skills. Unlimited instances of servers are made available virtually and cost effectively. SMBs can use this IT infrastructure to build new versions of applications without investing in additional hardware resources. The IT resources can also be used for hosting enterprise websites and reaching out globally to customers leaving the non-core activities of website maintenance, such as traffic monitoring to experts who provide the infrastructure.
IaaS is priced on a pay-as-you-go model and organisations have to pay only for usage of instances of servers and the software environment loaded, in databases or web servers, application development environments or the amount of network traffic in and out of the server during usage.
Software as a Service (SaaS) options in the cloud are attractive to SMBs that do not want to invest money in purchasing software licenses. Software access is provided on demand and deployed over the Internet to the local system. The software runs behind a firewall on a local area network or a personal computer with the SaaS provider holding the license for the software. The pay-as-you-go model is advantageous to the user. The software is accessible from anywhere with an Internet connection. There is no local server installation required and can be rapidly scaled and eminently reliable. System maintenance and security improvements are the responsibility of the SaaS vendor.
Platform as a Service (PaaS) delivers a computing platform and a solution stack to the IT constrained organisation. PaaS is an uncomplicated offering of web-based applications and services. The user does not have to worry about the underlying hardware or the complexities of the software being used to deliver the service.
PaaS includes facilities for application design, application development, testing, deploying and hosting of application services for collaboration, web service integration, marshalling, database integration, security, scalability, storage, persistence, state management, application versioning and facilitation of a host of other services. All these solutions are provisioned and delivered via the web using the Internet.
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 — https://en.wikipedia.org/wiki/Eliyahu_M._Goldratt