There is a lot of talk about “The Cloud” lately. While those of us at CWS are not “experts” in current Internet slang, there is some misuse of the term “cloud” in a lot of what is being written, and we’ll attempt to distill this down into something that hopefully is easier for the lay-person to understand.
Speaking in generalities, one could say that a “cloud” is any data that is not stored on your own computer or network, but somehow stored on the Internet. This is not entirely true. For decades, data has been stored on individual servers on the Internet. The majority of websites today, for that matter, are stored on single, individual servers through which developers upload content via FTP or other means. Even some of your email has been stored on servers, and has been for decades.
An individual server is considered to be one instance of hardware, with your data stored on a physical device on that hardware. Even on a peer to peer network, your computing is performed on the machine in front of you, but your data is physically located on your own computer or on other computers on your network. One way to summarize this: data on a computer or server can be said to be “device dependent.”
In our line of work, we consider a cloud to be sort of a vague representation of a typical physical computer. In cloud storage, your data does not exactly reside on one specific server; rather, it is stored in a redundant way across many servers. The idea is that if one server fails, the others still host your redundant data. You are not purchasing space on a single server; instead, you are purchasing the right to use a specific amount of storage using a redundant array of physical storage. Your data is now device independent; it is stored, but it does not concern you how or where it is stored…as long as you have access to it.
You can also use a cloud for computing. Web services use this rather than hosting physical servers themselves, or renting space on a single server (or group of servers) at a hosting company. What you do is setup what are called “virtual machines” or in essence, a running and fully operating remote instance of an operating system. It does not matter what computer your operating system runs on–all you need to know is that you have that instance available for your use. It is no longer relevant as to what your OS is running on, since that instance can run pretty much anywhere in the cloud. This makes your actual computing resources device independent.
But, why do this in the cloud? Other than being redundant (there is no such thing as “hardware failure” as you may have experienced in a physical server), it is possible to resize your running instance on the fly, simply by logging into a control panel. If you need more computing power to run a database, all you need to do is make some adjustments in your account, and the resources are allocated to you.
With a physical server, an upgrade of this type may require moving your data to a new server with more capacity, and that results in a lot of labor and costly downtime. As mentioned above, your computing resources are no longer tied to the idea of a physical computer but, rather, an “instance” that functions as a physical computer does, without the limitations therein. Again, device independent.
With Amazon’s cloud services, their philosophy is to provide a tremendous amount of computing power using common, inexpensive computing hardware. An array of computers that make up a “cloud” service may number in the thousands or tens of thousands, inexpensive so they may be replaced quickly and easily without any downtime or major cost outlay. Based on prices for many of Amazon’s services, they are indeed very inexpensive for the amount of computing power you receive.
One bothersome trend is for some hardware and software vendors selling something to give you “your own personal cloud.” It doesn’t quite work that way. One such device was a network hard drive for your home network. This is really nothing more than network attached storage (NAS) with software that lets you use it more easily on your network or remotely. It is still data tied specifically to one individual device. Storing all of your music files on this device is much different than uploading music to Amazon’s Cloud music service or Google Music, both of which are device independent storage services. All you need to know is your space limit; you need not worry about what it’s stored on, or how to access it. It is just always there for you to access.