In July 1990, NEC announced the N7795 high-capacity hard disk unit together with the ACOS System 3800.
This unit was an extension of the N7768 hard disk unit, which employed a 9-inch plated disk and was shipped in 1989 while large hard disk units were switching from 14-inch to 9-inch disks. It achieved greater compactness, higher density and greater capacity, and higher data transfer speed by using a thin-film magnetic head, thin-film (plated) magnetic disk media, improved servo circuits, the 1-7 RLL modulation code, and other improvements.
As a product, NEC also offered a model which had half the memory capacity because the cylinders accessed were limited to half the area, but speed was increased by reducing average seek time from 12msec to 10msec.
|Average seek time(msec)||12|
|Average rotational delay(msec)||8.1|
|Data transfer speed(MB/sec)||4.5|
|Number of disks||9|
|Number of heads(information recording part)||15|
|Number of cylinders (figure in parentheses is for alternates)||2742+(4)|
|Total memory capacity(GB)(entire unit)||22.8|
|Unit dimensions(mm) (entire unit)||825(W)×780(D)×1790(H)|