【NEC】 D3116 and D3126 Hard Disk Units

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.

Specifications of D3116,D3126 Magnetic Disk Units and Others
Model name D3116 D3126 D3126H D3146H
Disk diameter(inch) 3.5
Number of disks 1 2 2 4
Number of heads 2 4 4 8
Number of cylinders 615
Recording density(bpi) 15000 14000
Track density(tpi) 750 850
Recording system MFM
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
Rotation speed(rpm) 3564 3600
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

D3116/D3126 Magnetic Disk