Hardware Reference
In-Depth Information
The 1.8-inch form factor is also being used by SSD manufacturers such as AMP, Intel,
Kingston, KingSpec, and OCZ.
To learn more about SSDs, see “ SSD (Solid-State Drive) in Chapter 10 .
1-Inch Drives
In1998,IBM introduced a 1-inch drive called the Microdrive, incorporating a single plat-
ter about the size of a quarter! Seagate released similar drives in 2004. Microdrive ca-
pacities varied from 170MB to 12GB over the life of these products. These drives were
availablewithseveralinterfaces,butthemostpopularwasthatofaTypeIICompactFlash
(CF) card. This meant the drives could be used in almost any device that took CF cards,
includingdigitalcameras,personaldigitalassistants(PDAs),andMP3playerssuchasthe
Apple iPod Mini. IBM's disk drive division was sold to Hitachi in 2003 and combined
with Hitachi's storage technology business as Hitachi Global Storage Technologies. Hit-
achi and Seagate phased out Microdrive production after 2008 since by then flash-based
CF cards had surpassed the Microdrives in capacity, performance, and price.
Note
HPintroduceda20MB1.3-inchdiskdrivecalledtheKittyHawkin1992,originallyintended
for the handheld computer market. In 1994, HP followed with a 40MB model. These small
driveswereexpensiveandprovedtobetoofaraheadoftheirtime,aswerethehandheldcom-
puters they were intended for. After two years of low sales, HP discontinued the KittyHawk
family.
In 2004, Toshiba introduced the smallest drive to date: the 0.85-inch drive, which is about
the size of a postage stamp and stores up to 4GB. This drive was designed for use in cell
phones, digital audio players, PDAs, digital still cameras, camcorders, and more. As with
the Microdrive, these were eventually discontinued due to the advances in flash memory.
HDD Operation
The basic physical construction of an HDD consists of spinning disks with heads that
move over the disks and store data in tracks and sectors. The heads read and write data
in concentric rings called tracks , which are divided into segments called sectors , which
typically store 512 or 4,096 bytes each (see Figure 9.2 ) .
Figure 9.2 The tracks and sectors on a disk.
 
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