The Postfix mail server package was written to run on a Unix platform. The Unix operating systems provide the file and process control that Postfix requires to handle multiple processes and files.
The core of the Unix operating system is the kernel. The kernel controls many facets of the operating system, including memory management, process management, device management, and filesystem management.
Postfix can run on many different Unix platforms. The Linux distributions are excellent Unix implementations that are available for minimal or no cost. The core of Linux is the Linux kernel. Along with the kernel, the Bourne-again shell (bash) and the Linux C libraries combine to make a complete system.
Linux uses many utilities developed by the GNU Project. It uses gcc to compile C programs. To aid in compiling complex programs (such as Postfix), the GNU make utility is often used to create scripts to allow all of the source code modules to be compiled in a single command. With Postfix, Linux, and the GNU utilities, you can easily turn a standard IBM-compatible computer into a full-featured e-mail server.