So, what is cloud? Well, before we try to understand what is cloud, let’s see why do we even need cloud in the first place, or what is the problem that cloud solves. Before we had cloud, how did we store data? So, let’s say you had some pictures or some important documents with you that you wanted to save. Before cloud, you would save them on your desktop or laptop’s hard disk, or if your computer did not have enough space left, you would bring an external hard drive or pen drive, plug it into your laptop and save the data there. Right? But what if you run out of space on the additional hard drive and you have more data to be saved. What do you do then? Simple, you purchase additional hard drive, perhaps a bigger capacity one this time. Right? Now, as you may notice, there are two main problems with storing data like this – scalability and accessibility:
Scalability: It means the ability to grow as and when needed. Without cloud, you have to anticipate your future usage and purchase hardware accordingly. So, if you currently have, let’s say 50gigs of data and you need to purchase an external hard drive to store it, you wouldn’t just purchase a 50GB hard drive. Will you? You will anticipate your future storage needs and purchase a hard drive that can satisfy your current as well as expected future needs. However, the problem with this approach is you can’t always be sure of your future needs. So, you may end up either underutilizing your hardware i.e. storing much smaller amount of data than the hardware is capable of, or utilizing it to its maximum capacity and then having to purchase additional hardware. In other words, this traditional approach isn’t “scalable”.
Accessibility: This is about limited access to the data. In other words, without cloud, whenever you want to access your data, you must have your laptop or your external hard drive with you. If you don’t have that, you can’t access your data. Not very convenient.
So, where does “cloud” fit into all that? Well, cloud solves both of these problems for you as cloud is scalable as well as accessible. How’s that? Let’s see.
So, what is cloud? In very simple terms, cloud simply means that you are storing your data NOT on your own physical hardware like laptop or external hard drive. Instead, you are storing it on someone else’s hardware – most likely some big company’s hardware like Google, Amazon or Microsoft – somewhere on the internet and that hardware, virtually, doesn’t have any storage limits. You can keep adding data to it as and when you want, as much as you want, at a very nominal price. So that solves the first problem of scalability because now you don’t need to worry about purchasing new hardware and you can store as much data as you want without worrying about space issue. You always have enough space and you are charged according to the space you consume. Now coming to the second problem – accessibility, which, if you remember, meant that you had to have your hardware with you whenever you wanted to access your data. Now, with cloud, since you are storing your data somewhere on the internet, you have access to it all the time as long as you have access to the internet. So the second problem of accessibility is also solved (NOTE: accessibility can also be referred as availability).
Now, how does it all work. Well, there are various companies which provide you cloud services. That means they provide you certain services, like storage, over the internet. Some examples of such companies are AWS (Amazon Web Services) from Amazon, Azure from Microsoft, Gsuite from Google, etc. These cloud providers have their data centers setup all over world. When you save your data in the “cloud” with one of these companies, your data gets stored in one of their data centers, most likely to the one that’s closest to your location. And whenever you want to retrieve your data, just plug in a device to the internet and you can access your data.
So, once again, what is cloud? Cloud, in very simple terms, means that you are storing your data somewhere on the internet on someone else’s hardware. When you store data on the cloud, you don’t know where exactly the data is going to be saved. You just know that it will be stored somewhere on the internet and you can retrieve it whenever you want as long as you have access to the internet. The data is still being stored on hardware but on someone else’s hardware.
So, I hope now you are clear with the term “cloud storage”. But cloud is not just about storing data. It has evolved into much more than that. These days, you can be provided a lot of services over the cloud, not just storage. For example, you may have heard the term cloud computing. The same concept of cloud storage can be applied to cloud computing as well, so when you hear the term “Cloud computing”, it means computing services are being provided over the internet. In other words, you are not using the computing services like RAM, CPU, hard disk of your own hardware but someone else’s, from somewhere on the internet. You are just paying for the computing services being provided to you.
So, what exactly does the word “cloud” depict? It simply depicts that it is providing you a service e.g. storage or computing like I just mentioned, but you don’t really care or even need to know about how those services are being provided to you. In other words, the real working of the way the service is being provided to you is hidden behind the so called cloud.
Let’s take another example. You must have seen network diagrams that show a head office connected to various branch offices over WAN and the WAN is depicted using a cloud picture. In the context of such diagrams, cloud means that the two sites are connected “somehow”. They could be using some method like MPLS, leased line or some private link but we don’t really care about those details for the purposes of this diagram. All we care about is that the two sites are able to connect to each other “somehow”. Hence, the “cloud” in between. So, basically, cloud depicts that you are getting some services over the internet. You don’t always know the exact intricacies involved in you getting those services but you don’t even care to know the inside details as you are not responsible to take care of those details. You just get the service you need like storage, connectivity or computing. You pay for those services and that’s all you care about.
I hope that helped you understand, at a high level, at conceptual level, what cloud means and what it is.