 It was often used when reinstalling the operating system of an Apple Macintosh computer, or to repair corrupt partition information on a SCSI hard disk.Prior to its introduction, the formatting of disks was handled exclusively by the Mac's Finder application, or by third-party formatting utility software customized for a specific disk drive.The version of Apple HD SC Setup that shipped with the classic Mac OS was only able to manipulate hard disks that featured Apple ROMs.