Disk Manager was a popular 1980s and 1990s software and documentation package for MS-DOS and PC DOS computers, useful for self-installing PC hard disks. It was written by Ontrack.
Installation covered different aspects:
Drivers could be either DOS-type, or replacement Master Boot Record code.
Diskettes with Disk Manager were provided by some disk manufacturers (eg. IBM), in custom OEM versions, supporting all of their models.
In the recent years the company has switched to the business of providing disk recovery services and changed its name to Ontrack Data Recovery.