A number of vendor roles are commonplace in the mainframe shop.

Because most mainframe computers are sold by IBM®, and the operating systems and primary online systems are also provided by IBM, most vendor contacts are IBM employees. However, independent software vendor (ISV) products are also used in the IBM mainframe environment, and customers use original equipment manufacturer (OEM) hardware, such as disk and tape storage devices, as well.

Typical vendor roles follow:

Hardware support or customer engineer

Hardware vendors usually provide on-site support for hardware devices. The IBM hardware maintenance person is often referred to as the customer engineer (CE). The CE provides installation and repair service for the mainframe hardware and peripherals. The CE usually works directly with the operations teams when hardware fails or new hardware is being installed.

Software support

A number of vendor roles exist to support software products on the mainframe. IBM has a centralized Support Center that provides entitled and extra-charge support for software defects or usage assistance. There are also information technology specialists and architects who can be engaged to provide additional pre- and post-sales support for software products, depending upon the size of the enterprise and the particular customer situation.

Field technical sales support, systems engineer, or client representative

For larger mainframe accounts, IBM and other vendors provide face-to-face sales support. The vendor representatives specialize in various types of hardware or software product families and call on the part of the customer organization that influences the product purchases. At IBM, the technical sales specialist is referred to as the field technical sales support (FTSS) person, or by the older term, systems engineer (SE).

For larger mainframe accounts, IBM frequently assigns a client representative, who is attuned to the business issues of a particular industry sector, to work exclusively with a small number of customers. The client representative acts as the general "single point of contact" between the customer and the various organizations within IBM.