Computer software is a general term for any kind of computer program, which is designed to tell the computer what to do. The name “software” comes from the fact that most programs are stored in a different format than the data stored on a hard drive, and that this information has to be “interpreted” by a special piece of hardware called a central processing unit (or CPU) before it can be used by the computer.
Software is used in almost every computer system, from mainframes and supercomputers to a wristwatch.
Informally, the term “program” is often used to distinguish software from hardware (desk calculators and the like); usually programs are stored in computers’ memory or on storage devices, while hardware remains separate. Informally the term “software” encompasses both the code that implements a particular application as well as its human-readable source code and associated non-executable build scripts.
Information technology has sometimes been presented as a system of software, although those systems were not intended to be comprehensive, and for many technologies the software is not actually informally called “information technology”, but rather something else.
Computers are embedded in almost everything, from cell phones and refrigerators to automobiles and television weather reports. These computers run software, which accomplishes various tasks. Software is also used to control machines and devices not traditionally considered computers, such as robots and industrial machinery. The Internet runs on software.
Programs as a service (or more generally, cloud computing) is a way of delivering either all or some computer programs over the Internet in such a way that the programs are available at any time on any storage device connected to the Internet. Cloud computing is a kind of service you can use without staff to install, operate or support the technology yourself.
The cloud computing paradigm is not limited to the Internet. It means that any program can be installed and run by anyone on any device at any location via local access or via a mobile device. A program might be written running in the air, on a bus, or on a train – or it might be written and run from within an office building or home. In this sense a cloud is not necessarily the Internet, but it may be accessed via the Internet or any other network.
Containers are a lightweight alternative to virtual machines. A container allows a single operating system to run multiple isolated programs. Using containers means you can run multiple applications on one host without having to install multiple OS’s and without worrying about conflicting dependencies. Containers are a great way to set up isolated environments, so you can run various parts of a larger project on different servers, but still have them talking to each other. For instance, you could have a database running in one container, and an API running in another.
By now, most companies already use some kind of cloud computing solution like Microsoft Azure or AWS. Moreover, it is easy to learn how to work with cloud platforms and almost every developer knows how to setup an application on these systems. The problem is that the application will be accessible only from the cloud platform and if you want to run it on your own machines, you would need to replicate it on each machine. Container technology enables you to easily migrate your applications from one cloud platform to another and keep all of their functionality working. Thus, this technology can save a lot of time and money in labor cost, since it eliminates the need for repeating all development work (i.e. writing your code, compiling it and testing it).
Why do we use containers? Containers are lightweight virtual machines. Many people think that containers offer faster performance than virtual machines. Depending on the workload, containers will provide performance similar to or better than virtual machines. However, for clustered applications with hundreds of VMs, I can’t imagine that a container will be faster than a VM running on a high-end server.