Data recovery - Hard Disk Repair

1. Data storage devices.
2. What is a hard drive ?
3. Hard drive partitions.

1. Data storage devices

Storage media are magnetic storage devices where the data that we need to use is stored, such as software, documents, files, folders...

Types of storage devices:
• Hard drive (hard disk)
• Floppy disk
• ZIP/JAZ devices
• CD-ROM
• DVD
• Magnetic and optical devices

2. What is a hard drive?

The hard drive is an electro-mechanical and magnetic storage device that is usually inside the computer. It stores all personal data, operating systems, programs, files, documents...

•Main components of a hard disk:

ROTATING DISCS WITH MAGNETIC SURFACE: also called magnetic plates. Each one has a number of tracks where data is stored, like applications or programs.

READING HEAD: there is one in each plate, or depending on the number of plates of each hard disk there may be a number of heads. These read information from, and write information to, your hard drive.

MOTOR: this moves the head and spins the magnetic plates looking for the data stored in specified tracks and sectors...

Storage capacity is measured in bytes, kilobytes (Kb), megabytes (Mb), Gigabytes (Gb) or Terabytes (Tb). The greater the storage capacity of the hard disk, the greater will be the structure storing the data.

The hard disk is controlled by an electronic card called the PCB.

3. Hard drive partitions

• What is a partition ?

Partitions on the hard drive are the means of dividing the physical drive into several logical drives. Another way of putting it is to say that when we partition a hard drive, we divide the drive into several independent parts, creating the illusion of different drives, when it is really a single physical drive. A partition is one of these divisions of the drive.

• Why use partitions ?

Drives need to be partitioned so that the data is stored in an orderly fashion so that the Operating System understands and can find the location of any data.

There are many kinds of file systems which depend mainly on the Operating System used:

- FAT16, FAT32, NTFS, EXT2, EXT3, JFS, XFS, UDF.