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May 13, 1998

Hitachi Releases 2.5" HDD with Giant Magnetoresistive Heads for Notebook PC

- Provides large capacity of 6.48 GB in slim form factor -

With their low power requirements and small size, notebook PCs are being increasingly used in the office as well as for mobile computing applications, and are being required to handle large amounts of information such as Internet-based video and sound data. This is generating a demand for high-performance 2.5-inch drives with large storage capacities.

The higher recording density capability of the GMR head led Hitachi to the development of a hard disk drive that employs GMR heads, which also required the development of materials able to withstand high temperatures.

The GMR head developed by Hitachi provides the DK228A-65 with an areal recording density of 3.9 gigabits per square inch, resulting in the large storage capacity of 6.48 GB. Compared to Hitachi's 5.02-GB DK227A-50 drive that uses conventional magnetoresistive (MR) heads, this represents a 1.3-fold increase in storage capacity, and is enough to store over three hours of MPEG2 video data. Disk speed has also been raised to 4,200 RPM compared to the 4,000 RPM of the DK227A-50.

The combination of the GMR heads and the higher disk speed results in a transfer rate (during media read/write operations) of up to 13.4 MB/s. A seek time of 12 ms is achieved through the use of high-speed access technology. The DK228A-65 uses a standard ATA-4 (Ultra DMA 2) interface.

Notes:

• Giant Magnetoresistive: This refers to magnetic- field based changes in magnetoresistivity ranging from 5% to several tens of percent that take place in a multilayer structure of magnetic and non-magnetic films each having a thickness measured in nanometers.
• GMR head: The latest read/write heads for high recording density applications that use GMR elements that are several times more sensitive than a conventional magnetoresistive head.
• 1 gigabyte = 1 billion bytes. 6.48 gigabytes is equivalent to the storage capacity of around 4,500 floppy disks.
• MPEG2 (Moving Picture Experts Group Phase 2): An international standard method of compressing moving pictures.

Price:	120,000 yen (sample price, tax not included)
Availability:	Samples in the end of May 1998. Volume production in the end of June 1998.

Key Specification Summary

		Model
		DK228A-65
Capacity (formatted)		6.48 GB
Sector Capacity		512 B
Number of disk platters		3
Number of read/write heads		6
User cylinders		8,968
Seek time (nominal)	Average	12 ms
	Maximum	24 ms
	Minimum	3 ms
Average rotational latency		7.1 ms
Rotation speed		4,200 RPM
Linear bit density, maximum		250.5 kBPI
Track density		15.6 kTPI
Recording Technology		EPRML,ID-less format
Interface		ATA-4(IDE)
Media data transfer rate		CENTER>8.61 TO 13.43 MB/s
Interface data transfer rate		Max. 16.6 MB/s (PIO Mode 4, DMA 2) Max. 33.3 MB/s (Ultra DMA 2)
Data buffer size		512kB
Spin-up time	At Power-on	5.0 seconds typical (20.0 seconds max.)
	From Standby/Sleep	3.0 seconds typical (20.0 seconds max.)
Dimensions (Width x Depth x Height)		70 x 100 x 12.7 mm
Weight (Typical)		Approx. 130 g
Power Start-up Idle Seek Read/Write Stand-by Sleep		+5.5v +/- 5% 0.9 A typical 0.19 A typical 0.48 A typica 0.46 A typical 0.05 A typical 0.02 A typical
Energy consumption Rate		0.00015 W/MB

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