When you install OS/2 2.0, it replaces any existing version of the operating system. For example, if OS/2 Standard Edition Version 1.3 is on the hard disk, OS/2 2.0 will replace the operating-system files, but will leave other programs and data intact. However, if you want to keep the earlier version of the OS/2 operating system on the hard disk (so that both versions are available) and there is at least 1MB of free space on the hard disk (for the Boot Manager partition), you can install the Boot Manager during the OS/2 installation.