You have a machine. The machine has a BIOS (Basic Input/Output System). The BIOS will load the boot sector of the storage device. From the boot sector, the OS (Operating System) will be booted. The kernel of the OS will manage every device, including the memory. That is why we no need bother how memory works when we run multiple processes. To interact with the OS kernel, we need to use the shell. Through the shell, we request the OS to start a process to complete our task. Windows is the most popular OS. We can find that there is kernel32.dll in Windows XP. The kernel32.dll is a dynamic-linking library, which can be considered as a shared library. There are a lot of functions provided by kernel32.dll. Thus, anyone who is developing Win32 API application needs to learn about Win32 API functions. And the functions of the kernel32.dll are called. However, to divide the tasks, there are other Win32 DLL such as gdi32.dll, user32.dll, etc. Linux is actually a kernel. There are various types of distributions. Because the developers package the applications and libraries which depends on the Linux kernel. Though different distributions, but they are all using Linux kernel. FreeBSD, another UNIX type OS. It is different from Linux, though the applications and libraries are similar, because it uses kernel different from Linux. |