According to Wikipedia:
What this means is that end users connect to servers in another location, thanks to the internet, in order to perform tasks. It is almost as if technology has come back around to the days of the main frame and dummy terminal. However nowadays we have speeds that make this feel like you are on your own computer. The cloud allows us to essential store nothing on our own computers, only using them as a portal to our software and data.
The Cloud, or Cloud Computing, is a term used to refer to a model of network computing where a program or application runs on a connected server or servers rather than on a local computing device.
The term “Cloud” came from network diagrams. It was common practice when drawing network diagrams to use a cloud symbol to denote unknown segments of the network. The cloud originally contained all components external to physical location of the business.
Today we have a multitude of different cloud set up. In Jeff Borshowa’s book, 8 Pillars for Exponential Business Growth, Jeff lists the deployment models and variations.
Models & Variations of Cloud
• PRIVATE CLOUD – dedicated resources for your needs, behind a corporate firewall
Within each of these deployment models, there are several variations in terms of service models:
• PUBLIC CLOUD – shared resources available to the public over the Internet
• COMMUNITY CLOUD – resources shared between organizations
• HYBRID CLOUD – combination of private, public, and/or community
• SOFTWARE AS A SERVICE (SaaS) – software is licensed on a subscription basis and is centrally hosted on the cloud.
All “as-a-service” offerings have low initial cost, incremental cost based on usage, self-service, and offer a great degree of scalability.
• INFRASTRUCTURE AS A SERVICE (IaaS) – Physical or virtual machines are shared via the cloud.
• PLATFORM AS A SERVICE (PaaS) – the consumer creates an application or service using tools from the provider.