Operating systems use different file systems. The Windows series up to the XP release used FAT32, and the NT series used NTFS. Linux can read and write to those file systems, but runs on a different file system itself – in fact several of them are available. The main file systems that Linux uses are ext2, ext3, reiserfs, xfs, and jfs. However, most of the time ext3 is now preferred, which we will continue with throughout the article.
In order to have more than one operating system on the same disk, the disk should be so arranged that there is a separate space for each operating system, plus the space to be formatted by the operating system’s native partition. So, if we will have two operating systems, Linux and Windows on the same hard disk, then Windows space will be formatted with NTFS (if NT, XP or Vista to be installed), and the Linux space will be formatted with ext3.
In order to avoid tweaking with the boot loaders after the installation, I recommend that you install Windows first and then Linux afterward. The reason is that Linux can recognize and change the Windows boot loader accordingly, but this is not true the other way.