Introduction
Cloud computing or store in cloud is becoming a common phrase in daily language. What does cloud computing mean? What, and where is the cloud? What are the benefits of the cloud? Before we get into the definitions, let us take an example most of us can relate in terms of working at a company or owning a desktop or laptop.
Example
About 25-35 years ago it was common to go out and buy a computer with memory (RAM- Random Access Memory), hard drive, and other features on it. This is infrastructure and some households and business owned them rather than leasing them.
An individual either owned a specific operating system on the infrastructure i.e. either Windows Operating System (with DoS- Diskette operating System) or Mac OS (and later flavors of Unix). These operating systems are called platforms.
Finally, each company or individual had to buy software which was compatible to run on their operating system. This is software which is commercial or written in house.
Now assume you had a desktop, laptop etc. with windows OS and running MS Office on it. This is owning by you or your company and is called on-site premise infrastructure, platform and software.
When MS Office upgraded its’ software then you would have to buy it, however the latest version of MS Office may not work on Windows OS and you have upgrade the Windows OS to the latest (say Windows 2000). Unfortunately, Windows 2000 needs more infrastructure (say memory, or hard disk space etc). Now owning an infrastructure is not sounding as economical and what does one do with the old infrastructure with an old OS and old version of Software?
So how about, let somebody own the infrastructure, the operating system and even the software and I will pay them to use it! Let them worry about upgrades etc..
Yes! we can do this and that is what we term as a Cloud!
As you know by now, Office 365 is Software as a Service (SaaS) which runs on a platform (maybe windows 2000 or some other latest windows OS) which is the Platform as a Service (PaaS) and finally the operating system is running on some servers (possibly Microsoft owned servers) which is Infrastructure as a Service.
Let us show how this all in a diagram:
Now you know what IaaS, PaaS and SaaS is! In Information Technology field, there are different personnel who are responsible for IaaS, PaaS and SaaS, which is out of the scope of this article.
Where is the cloud?
The cloud is a network of computers which can be located physically wherever the vendor has space to have servers. So is all over. Where is my data ? Your data is stored on some server possibly in Scotland or literally on the next street in the vendors’ computer servers location. And it will not be static since if one of the server goes down another server (a copy of the server which went down) will come alive and present the data to you.
What are the benefits?
The best way to talk about benefits is to show in a picture:
Conclusion
Cloud computing consists of infrastructure (hardware), platform (operating systems) and software (subscribe to use the application). This gives benefits to user and companies as having latest version of all three, scaling automatically and minimizing costs.
Let us conclude with a making and delivery of a pizza from the perspective of IaaS, PaaS and SaaS.
As can be seen above, making a pizza at home is like On-Premise, while if we can go to a place where we use the kitchen, and their oven and gas then it is Infrastructure as a Service (IaaS), while a Walkin-bake where even the dough is given by them while toppings and the cook is customer then we have Platform as a Service. While delivery is analogous to Software as a Service (SaaS).
