In July 1985, NEC announced the D3116 and D3126 3.5-inch hard disk units for OEM.
These units achieved high recording density by using the first plated disk media for 3.5-inch, ensured reliability at high track densities by employing the same embedded servo system for head positioning control as the D5126 5-inch fixed disk, and achieved the highest capacity in Japan at the time for a 3.5-inch fixed disk (25MB with the D3126) in almost the same size as a 3.5-inch micro floppy disk unit.
In 1987, NEC shipped the D3126H, which improved average seek time from 85msec to 35msec by changing the magnetic head movement system from a step motor to a torque motor, and the D3146H which doubled the number of disks while keeping the same magnetic head system, and increased memory capacity to 51MB.
|Number of disks||1||2||2||4|
|Number of heads||2||4||4||8|
|Number of cylinders||615|
|Memory capacity (unformatted)(MB)||12.8||25.6||25.6||51.2|
|Average seek time(msec)||85||35|
|Average rotational delay(msec)||8.42||8.33|
|Data transfer speed(kB/sec)||625|
|Unit diamensions (mm)||101.6(W)×151(D)×40.6(H)||101.6(W)×146(D)×41.3(H)|
|Date first shipped||March 1985||September 1985||October 1987||June 1987|