Can anyone enlighten me about windows posix compliant?

Linux is, at first glance, an operating system. It is a freely available UNIX implementation for personal computers (PCs), servers and workstations. It was developed for the i386 and i486 processors now support, Pentium, Pentium Pro and Pentium II and AMD and Cyrix clones. It also supports SPARC-based machines, DEC Alpha, PowerPC / PowerMac, and Mac / Amiga Motorola 680x0.

As operating system, Linux is very efficient and has an excellent design. It's multitasking, multiuser, multi-platform and, on Intel platforms running in protected mode, protects memory so that a program cannot bring down the rest of the system load only the parts of a program that uses and shares memory between programs increasing speed and decreasing memory usage, uses a virtual memory system pages, uses all free memory to cache, allows the use both statically linked libraries dynamically, is distributed with source code, uses up to 64 virtual consoles, has an advanced file system but can use other systems, and networks supports both TCP / IP and other protocols.
The cross-platform applications are those that can run on different operating systems and / or computers, but the source code is the same. Programmers tend to write programs only valid for our platform, forgetting that there are users who work in others.

One of the great advantages of cross-platform applications is that they give the user freedom to use the machine that you like. Some users prefer Linux (like me), others prefer Windows, some Mac, etc.. The user should be able to choose from. Normally, the manufacturers are deciding for us when they make a new software is available for the machines they choose.

This technical book explains how to develop applications for the console (no graphics) in a Linux environment that can be compiled for.

In addition, the time required and the process was far too slow, then more elaborate means were sought to manipulate the computer. That's when the idea of ​​creating a way for the user to operate the computer with an environment, language and well-defined operation to make a real use and exploitation of this emerging operating systems.