OS/360 Object File Format
From Just Solve the File Format Problem
OS/360 Object File Format is the original executable format for IBM mainframe operating system OS/360 and its successors. It is still supported by contemporary z/OS, although officially superseded by GOFF. It is also supported on z/VM (previously VM/CMS), although likewise superseded by GOFF there as well. It is also called "OBJ". There is also an extended version, which came after OBJ but before GOFF, called XOBJ, which has various important features, such as support for symbols with names longer than 8 bytes.
It was also used by some other mainframe vendors which partially copied IBM's technologies, such as UNIVAC Series 90.