What are the names of the manufacturers?

S.M.A.R.T. stands for Self-Monitoring Analysis and Reporting Technology. S.M.A.R.T. technology was developed by a number of major hard disk drive manufacturers to increase the reliability of hard drives. It is a technology that enables the PC to predict the future failure of hard disk drives. S.M.A.R.T. technology has become an industry standard for hard drive manufacturers.

"http://wiki.answers.com/Q/List_at_least_two_different_hard_drive_manufactures"

A computer hard disk or hard drive (fixed disk) is hardware.

Seagate
Samsung
Western Digital
Maxtor (now part of Seagate)
Conner Peripherals (now part of Seagate)
Hitachi