【Hitachi】 DK228A-65 2.5-inch Hard Disk Drive / DK239A-65 Hard Disk

The DK228A-65 was the first Hitachi drive to use GMR heads, which gave a recording capacity of 6.48 GB, about 1.3 times more than conventional MR-head drives. The disk speed was also boosted to 4,200 rpm from the 4,000 rpm of previous models. Together, the GMR head and faster disk speed enabled a maximum data transfer speed of 13.4 MB per second, which improved the drive’s overall processing speed. The drive had an ATA-4 interface, which was the industry standard at the time.

As more hard disk drives were installed in notebook computers and other portable devices, vibration and shock resistance requirements became more stringent. Hitachi released the DK239A-65 in November 1998, which featured a magnetic-head load/unload mechanism, a first for Hitachi.
As more people began travelling with and using notebooks with built-in 2.5-inch hard disk drives on the road, notebooks and other portable devices had to be built with more robust shock resistance. To dramatically improve the hard disk drive’s non-operation shock resistance, Hitachi made use of a load/unload mechanism that removed the magnetic head from the disk when not reading or writing. Furthermore, to raise the drive’s storage capacity to 6.49 GB, Hitachi incorporated a number of leading technologies at the time, such as MEEPRML signal processing and on-the-fly ECC correction.