Hard Disk Drive
The computer stores information that is permanent, on the Hard Disk platter. The Hard Disk is sealed in the Hard Disk Drive. The disc is made from aluminium with coating of magnetic material such as ferric oxide or chromium oxide. The Hard Disk Drive is very sensitive to shock and electrostatic discharge.
Data is stored on the surface of a platter in sectors and tracks. Tracks are concentric circles, and sectors are pie-shaped wedges on a track with magnetic marking and an ID number, Sectors have a sector header and an error correction code (ECC). In modern drives, sectors are numbered sequentially. A sector contains a fixed number of bytes -for example, 256 or 512. Either at the drive or the operating system level, sectors are often grouped together into clusters.
- Cylinder
A group of tracks with the same radius is called a cylinder.
- Data addressing
There are two methods for Drive's data addressing: CHS (cylinder-head-sector) and LBA (logical block address). CHS is used on most IDE drives, while LBA is used on SCSI and Enhanced IDE (EIDE) drives.
- Cluster
In a computer system, a cluster is a group of servers and other resources that act like a single system and enable high availability and, in some cases, load balancing and parallel processing. In personal computer storage technology, a cluster is the logical unit of file storage on a hard disk; it's managed by the computer's operating system. Any file stored on a hard disk takes up one or more clusters of storage. A file's clusters can be scattered among different locations on the hard disk.
Installation
- Turn off the computer, unplug the external cables, and open computer cover. Mount the Hard Disc in the designated place in the computer.
- Connect 40 pin interface cable and power cable. Make sure that the directions of the cables are correct and match the shape of the receptacles when connecting cables. Incorrect cable connection may damage the Hard Disk Drive.
- Let the Computer Detect the new Device. Run the CMOS (BIOS) set-up program to detect the new Hard Disk Drive manually.
Partitioning and formatting the Drive
There are two types of formatting: High Level and Low Level
- High Level Formatting
High Level Formatting initializes portions of the hard disk and creates the file system structures on the disk, such as the master boot record and the file allocation tables. High-level formatting prepares drive partitions for the operating system by creating a root directory, from which all other subdirectories could be created, and creating a File Allocation Table (FAT), which keeps track of all information on the disks and all the relationships between different pieces of information
- Low Level Formatting
Low Level Formatting creates the tracks and sectors on a hard disk. Low-level formatting creates the physical format that dictates where data is stored on the disk. At this stage, the drive is being physically divided into tracks and sectors. Low-level formatting stays unchanged for the entire life of the drive unless the drive is re-formatted. A low-level format is also called a physical format
