Adventures in Hard Drive Recovery

Hard Drive Recovery

Below you will find a list of some of the terms that crop up when discussing hard drive recovery. Some you may have encountered before on this site, while others may be completely new to you. All are terms however, with which you should familiarize yourself before attempting hard drive recovery.

Actuator - The moving arm that holds the Read/Write Heads accurately in place over the platter surfaces.

Bit - A single unit of data that has two values, 0 or 1.

Byte - A unit of data consisting of eight bits. Typically, each byte stores one alphanumeric character.

Cache - Also known as the buffer, the cache is the area on the hard drive, where recently accessed data, or data that is waiting to be written to the disk, is temporarily stored.

Cluster - A group of sectors.

Data - Information processed by a computer, or an ordered collection of information.

Disk - A flat, circular piece of metal or plastic with a magnetic coating upon which information can be recorded.

Fat (File Allocation Table) - A system stored in the data section of a hard drive that contains information about the size and location of a file.

Fat 16 - One of the first versions of the File Allocation Table.

Fat 32 - A more recent version of the File Allocation Table which uses space more efficiently.

Hard Drive - A storage device consisting of disks, Read/Write Heads, head positioning mechanisms, drive motors, and electronics.

Head - The electromagnetic device that writes, reads, and erases data on magnetic media.

Head Crash - The inadvertent touching of a disk by a head flying over the disk.

Head Disk Assembly (HDA) - The mechanical portion of a rigid, fixed hard drive. It usually includes disks, heads, spindle motor, and actuator.

Kilobyte - A unit of data consisting of approximately 1,000 bytes. However, because computer memory is partitioned into sizes that are a power of two, a kilobyte is really 1,024 bytes.

NTFS (New Technology File System) - A highly optimized file system used by Windows NT.

Platter - Magnetic disk memory media. Each platter (disk) has two surfaces, the top and bottom surface. Each surface has it's own Read/Write Head for reading, writing, and erasing data.

Read/Write Head- The recording element which writes data to the magnetic media and reads recorded data from the media.

Sector - A logical segment of information on a particular track. The smallest addressable unit of storage on a disk. Tracks are divided into sectors, each sector is 512 bytes long. They contain data, but also contain "housekeeping" information.

Spindle - The rotating hub structure to which the disks are attached.

Spindle Motor - The motor that rotates the spindle and therefore the disks.