Disk drive, double-sided

D. Double-sided 320K floppy drives were created was the major innovation that came after MS-DOS -1. At the time, hard drives were not easily available therefore, all information was stored on 5.25" floppy disk. 

Roll forming is a process used to manufacture flexible circuits in very large quantities. This is the lowest-cost method for the manufacture of flexible circuits. However, it involves substantial tooling, so it is apphcable only for very high volume products. Examples of PCBs manufactured using this method are printer head connections, disk drive head connections, and the circuits used in cameras and camcorders. The PCBs can be single- or double-sided. 

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