Apple HD SC Setup was a small software utility that was bundled with various versions of the classic Mac OS and A/UX operating systems made by Apple Computer. Introduced with Apple's first SCSI hard drive, the Hard Disk 20SC in September 1986, Apple HD SC Setup can update drivers and partition and initialize hard disks. 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, formatting of disks was handled exclusively by the Mac's Finder application, or third party formatting utility software customized for a specific disk drive.