Network computers part 1

When it became clear that the new technology enjoyed unprecedented demand, the developers wanted to consolidate and build on the success and prevalence of Java. To Java does not share the fate of NeWS (This window system is mentioned in the beginning of the lecture, she did not develop, losing X Window), Sun has tried to cooperate with independent firms to produce a variety of libraries, developer tools, tools. January 9, 1996 was formed a new division JavaSoft, which was engaged in and develop new Java-technologies and promote them to market. The main objective - the emergence of an increasing number of different applications that are written on this platform. For example, July 1, 1997, it was announced that scientists NASA (National Aeronautics and Space Administration, the U.S. government organization dealing with space exploration) with the Java-applet control robot, studying the surface of Mars ("Java help make history!").

It's time to dwell on why Java in relation to the term "platform" rather than Java is different from conventional programming language.

Typically, the platform is called a combination of hardware architecture ("iron"), which is determined by the type of processor used (Intel x86, Sun SPARC, PowerPC, etc.), with an operating system (MS Windows, Sun Solaris, Linux, Mac OS, etc.) . When writing software developer always use the means of the target platform for network access, support for threads of execution, the graphical user interface (GUI) and other features.Of course, different platforms, because of technical, historical and other reasons, support different interfaces (API, Application Programming Interface), and hence the program can be executed only by a platform under which it was written.

Often, however, customers want the same functionality, but they use different platforms.The task of porting applications to the developers is a long time. Rarely can not transfer a complex program without substantial alteration, very often different platforms in different ways is supported by many features (eg, operating system, Mac OS traditionally uses one-button mouse, while Windows was originally designed for a two-button).

This means that the programming languages ​​should be initially focused on any particular platform. The syntax and basic concepts can easily be extended to any system (although this is not always effective), but libraries, compiler, and, of course, the binary executable code specific to each platform. So it was from the beginning era of computing, but because only a few really successful programs maintained on multiple systems, which led to the isolation of some of the worlds of software for different operating systems.

It would be strange if the development of the computer industry, developers have not tried to create a universal platform which can work under all programs. Especially such a move would boost the development of the global network Internet, which brings together users, regardless of the type of processors and operating systems. That is why the founders conceived to develop Java is not just another programming language, a universal platform for application execution, especially since originally created for OaK various household appliances from which to wait for compatibility is not necessary.

How is it possible to "smooth" differences and diversity of operating systems? The method is not new, but effective - using a virtual machine. Java applications are executed in a special, universal medium, which is called the Java Virtual Machine. JVM - a program that is written specifically for each platform, the real, on the one hand, to hide all its features, but on the other - to provide a common runtime environment for Java-based applications. Firm Sun and its partners have created a JVM for virtually all modern operating systems. When it comes to a browser that supports Java, means that it has built a virtual machine.