Modern Information Systems

In practice, cloud service providers tend to offer services (ie. Cloud Computing Service Models)  that can be grouped into three categories: software as a service (SaaS), platform as a service (PaaS), and infrastructure as a service (Iaas).

1. Software as a service (SaaS)

Software as a service (SaaS)  is software that is developed and hosted by the SaaS vendor and which the end user accesses over the Internet. Unlike traditional applications that users install on their computers or servers, SaaS software is owned by the vendor and runs on computers in the vendor’s data center (or a collocation facility). A single instance of the software runs on the cloud and services multiple end users or client organizations.… Read the rest

There are many considerations for cloud computing architects to make when moving from a standard enterprise application deployment model to one based on cloud computing. There are three basic cloud computing models to consider, and they differed as the open APIs versus the proprietary ones. These are public, private and hybrid cloud and IT organization can choose to deploy applications according to their requirements.

IT organizations can choose to deploy applications on public, private, or hybrid clouds, each of which has its trade-offs. The terms public, private, and hybrid do not dictate location. While public clouds are typically “out there” on the Internet and private clouds are typically located on premises, a private cloud might be hosted at a collocation facility as well.… Read the rest

Cloud Computing Architecture

Cloud computing architecture, the systems architecture of the software systems involved in the delivery of cloud computing, typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services and 3-tier architecture. This resembles the Unix philosophy of having multiple programs each doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.

The two most significant components of cloud computing architecture are known as the front end and the back end. The front end is the part seen by the client, i.e.… Read the rest

As a metaphor for the Internet, “the cloud” is a familiar cliche, but when combined with “computing,” the meaning gets bigger and fuzzier. Some analysts and vendors define cloud computing narrowly as an updated version of utility computing: basically virtual servers available over the Internet. On the other hand others go very broad, arguing anything you consume outside the firewall is “in the cloud,” including conventional outsourcing.

The most common analogy to explain cloud computing is that of public utilities such as electricity, gas, and water. Just as centralized and standardized utilities free individuals from the vagaries of generating their own electricity or pumping their own water, cloud computing frees the user from having to deal with the physical, hardware aspects of a computer or the more mundane software maintenance tasks of possessing a physical computer in their home or office.… Read the rest