Tandon
Tandon was a prestigious manufacturer of disk drives and also of personal computers. The company was founded in 1975, initially creating heads for magnetic discs. It obtained a major contract with IBM; up until 1985 they were the only manufacturer of floppy drives for the IBM PC. In the mid-80s they began to create hard drives as well as removable hard drives. It also entered the personal computer market, but strong competition caused it to end up having losses, to sell the hard drive division in 1988 to Western Digital and to disappear from the North American market to the point that by 1989 90% of its computer sales were in Europe.
The Double-Density Floppy Disk
In the late 1970s, Tandon (Tandon Magnetics Corp.) started to develop equivalents to Shugart's floppy drives. Tandon invented the DS/DD (Double-Sided/Double-Density) version which became its primary product in the early 1980s. Until 1985, Tandon were the sole supplier of floppy drives for IBM PCs, initially the same single-sided unit used in the TRS-80, then the newer double-sided TM-100-2. Tandon would become the world's largest independent producer of disk drives for personal computers and word processors.
Moving into Hard Disk Drives
In the mid-1980s, Tandon introduced a line of hard disk drives, making several models of the same basic design with a P shaped top cover and a pinion rack stepper motor off to the side. They also introduced portable hard disk drives that could be easily removed from personal computers. A major decline in North American computer sales during 1984–85 as well as competition from Japanese and Taiwanese manufacturers proved difficult for the company. Tandon sold its original data-storage business to Western Digital for nearly $80 million in 1988, and brought in former IBM and other computer industry executives in an attempt to remake the company as a leading producer of personal computers.
PC Compatibles
This section needs more work, but basically Tandon moved into the PC compatible market with a range of XT-compatibles in the late 80s, and expanded on this with 286, 386 and even 486 computers. There might have even been some Pentium-class Tandons - I don't recall.
The Tandon PC-compatible range (March 1987)
more to follow...