 Executable binaries, such as applications and libraries, are also typically accessed through page cache and mapped to individual process spaces using virtual memory (this is done through the mmap system call on Unix-like operating systems).This not only means that the binary files are shared between separate processes, but also that unused parts of binaries will be flushed out of main memory eventually, leading to memory conservation.Since cached pages can be easily evicted and re-used, some operating systems, notably Windows NT, even report the page cache usage as "available" memory, while the memory is actually allocated to disk pages.