An operating system
(OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it.
Operating systems are found on many devices that contain a computer - from mobile phones, video game consoles, desktops to web servers and super-computers.
Servers and Clusters for Internet
In computing, a server
is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called "clients". This architecture is called the client-server model. A cluster is a group of computer (servers) which are linked together to act like a single computer.
Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client. A single server can serve multiple clients, and a single client can use multiple servers.
A client process may run on the same device or may connect over a network to a server on a different device. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, application servers, etc.
An embedded database
system is a database management system (DBMS) which is tightly integrated with an application software that requires access to stored data, such that the database system is "hidden" from the application's end-user and requires little or no ongoing maintenance.
They are not client-server database engines and require no server to manage the database operations which are all are implemented at the application level only.
Web Languages (Scripting Languages for Web)
Web development is the work involved in developing a Web site for the Internet (World Wide Web) or an intranet (a private network). It can range from developing a simple single static page of plain text to complex Web-based Internet applications (Web apps), electronic businesses, and social network services. A more comprehensive list of tasks to which Web development commonly refers, may include Web engineering, Web design, Web content development, client liaison, client-side/server-side scripting, Web server and network security configuration, and e-commerce development.
A programming language
is a formal language comprising a set of instructions that produce various kinds of output. Programming languages are used in computer programming to implement algorithms.
Thousands of different programming languages have been created, and more are being created every year. Many programming languages are written in an imperative form (i.e., as a sequence of operations to perform) while other languages use the declarative form (i.e. the desired result is specified, not how to achieve it).