【Hitachi】 DK211A-51 / DK211C-51 2.5-inch Hard Disk Drives

With the growing popularity of notebook computers, there was increased demand for smaller, lighter, and lower power hard disk drives. In addition to its regular 5.25-inch and 3.5-inch drives, Hitachi developed and marketed the DK211A-51 and DK211C-51, its first 2.5-inch hard disk drives.
The DK211A-51 and DK211C-51 offered 510 MB of storage, about the same as Hitachi’s 3.5-inch drives announced the previous year. The new drives were unique in that they operated on a single five-volt power supply and had an impact resistance while in operation of 100 G. The models differed only by their interface — an SCSI interface or an ATA interface — to match specific applications.

Specifications of the DK211A-51 and DK211C-51 hard disk drives
Model name DK211A-51 DK211C-51
Introduced November 1993
Storage capacity per unit 510 MB
Recording density 83,000 bytes per inch
Track density 3,500 tracks per inch
Area recording density 290 Mbits per square inch
Number of disks 3
Number of heads 6
Average seek time Read: 12 ms, write: 15 ms
Disk speed 4,464rpm
Data transfer speed 8 MB/s max. 10 MB/s max.
Interface PC ATSCSI-2


Magnetic Disk Units