mini hard disk
Miniature hard disk drives are used in laptops and notebooks but also used as external storage for small computers, handhelds, camcorders, MP3 players, and so on. Miniature hard disk drives have diameters of 3.5", 2.5", 1.8", 1.3", 1.0" and 0.85". The heights of miniature HDDs are in Half Height with 41 mm, in Low Profile with 25.4 mm and in 5 mm technology. They use Perpendicular Magnetic Recording( PMR) to increase storage density.
The 3.5" hard disks operate at rotational speeds of 5,400, 7,200, 10,000 and 15,000 rpm and offer storage capacities of over 1,000 GB. The smaller 2.5" hard disks have rotational speeds of 4,200 rpm, 5,400 rpm, 7,200 and 10,000 rpm and storage capacities of over 100 GB. Average access times are around 4 ms, and data transfer rates range up to 100 MB/s
The 1.8" hard disks are available with storage capacities of up to 250 GB. This corresponds to a storage density of 378 GB/sqinch. Data transfer rates of 3 Gbit/s are realized via the micro- SATA interface.
Miniature hard disks are available for installation in notebooks and laptops, as mobile high- performance storage for handhelds, camcorders or MP3 players, and in the form of a memory card for use in PC cards, such as IBM's Microdrive
The 1" hard disk impresses with its small dimensions, measuring only 40 x 30 x 5 mm and offering storage capacities of well over 10 GB. The currently smallest hard disk with 0.85" has a weight of less than 10 grams and dimensions of 32 x 24 x 5 mm. Its storage capacity is 10 GB, which corresponds to a storage density of around 200 Gbit/square inch.
With built-in mini hard disk drives, the connection is made via Integrated Drive Electronics( IDE) or Enhanced Integrated Drive Electronics( EIDE), but also via Ultra SCSI, FC interface or the Serial Attached SCSI( SAS), with external connection via Firewire or the USB interface. Data transfer rates of10 MB/s are achieved in both configurations, with FireWire and USB up to a maximum of 50 MB/s depending on the drive.