Click of death is a term that became common in the late 1990s referring to the clicking sound in disk storage systems that signals a disk drive has failed, often catastrophically.

The clicking sound itself arises from the unexpected movement of the disk’s read-write actuator. At startup, and during use, the disk head must move correctly and be able to confirm it is correctly tracking data on the disk. If the head fails to move as expected or upon moving cannot track the disk surface correctly, the disk controller may attempt to recover from the error by returning the head to its home position and then retrying, at times causing an audible “click”. In some devices, the process automatically retries causing a repeated clicking sound.

Hard Disk Drives

On a hard disk drive, the click of death refers to a similar phenomenon; the head actuator may click or knock as the drive repetitively tries to recover from one or more errors. These sounds can be the heads repetitively loading or unloading, or they can be the sounds of the actuator striking a stop, or both. The click of death may indicate that the hard drive has crashed or failed.

Source: http://en.wikipedia.org/wiki/Click_of_death

A hard drive, also known as a hard disk drive (HDD), is a fundamental part of modern computers. Functioning as an internal storage device, it allows a computer to house and execute important files and programs, like the machine’s operating system, and its components work together to actively seek, read, and write data on system and user-generated files. The delicate nature of the standard hard disk makes it susceptible to damage and data corruption or loss, however, and repairing or replacing one can be costly. Damage can often be avoided by minimizing the drive’s exposure to environmental factors, like dust and rough-handling.

There are two main types of hard drives: internal and external. The internal drive is the main storage area of a computer, and typically, the operating system as well as programs that are manually installed by the user are found here. Most computers designate it as the C drive, and program installation will occur on this primary partition by default. Modern computers often have several hundred gigabytes of storage, which provides enough room for the average user’s collection of applications, documents and media throughout the computer’s lifespan. An internal drive usually connects to the computer through either Parallel Advanced Technology (PATA), Serial ATA (SATA), or Small Computer System Interface (SCSI).

External drives are usually used to hold back-up copies of documents and programs, to store archived files, or to hold large data files that aren’t used regularly, among other things. They usually don’t include the operating system or any programs that are needed to make the computer work. Most connect to the machine through a USB or FireWire® connection, although some wireless models are also available. They are also sometimes called portable drives, since they can often easily be moved from one computer to another.

Source: http://www.wisegeek.com/what-is-a-hard-drive.htm

Although most hard drives are internal hard drives, many users also use external hard drives to backup data on their computer and expand the total amount of space available to them. External drives are often stored in an enclosure that helps protect the drive and allow it to interface with the computer, usually over USB or eSATA. A great example of a backup external device that supports multiple hard drives is the Drobo.

External hard drives come in many shapes and sizes. Some are large, about the size of a book, while others are about the size of a cell phone. External hard drives can be very useful for backing up important data and taking with you on the go. They can store a lot of information, including music and movies.

HDD being replaced by SSD

Solid State Drives (SSDs) are starting to replace hard disk drives (HDDs) in many computers because of the clear advantages these drives have over HDD. While SSD is becoming more and more popular, HDD will continue to be in desktop computers with SSD because of the available capacity HDD offers over SSD.

Source: http://www.computerhope.com/jargon/h/harddriv.htm

Disaster recovery (DR) is the process, policies and procedures that are related to preparing for recovery or continuation of technology infrastructure which are vital to an organization after a natural or human-induced disaster. Disaster recovery is a subset of business continuity. While business continuity involves planning for keeping all aspects of a business functioning in the midst of disruptive events, disaster recovery focuses on the IT or technology systems that support business functions.

Importance of disaster recovery planning

Recent research supports the idea that implementing a more holistic pre-disaster planning approach is more cost-effective in the long run. Every £1 spent on hazard mitigation(such as a disaster recovery plan)saves society £4 in response and recovery costs.

As IT systems have become increasingly critical to the smooth operation of a company, and arguably the economy as a whole, the importance of ensuring the continued operation of those systems, and their rapid recovery, has increased. For example, of companies that had a major loss of business data, 43% never reopen and 29% close within two years. As a result, preparation for continuation or recovery of systems needs to be taken very seriously. This involves a significant investment of time and money with the aim of ensuring minimal losses in the event of a disruptive event.

Source: http://en.wikipedia.org/wiki/Disaster_recovery

Shrewsbury is the county town of Shropshire, in the West Midlands region of England. Lying on the River Severn, The UK Parliament constituency of Shrewsbury and Atcham is home to some 102,234 inhabitants, whilst the town of Shrewsbury itself has a population of approximately 70,000 [6] and is the primary settlement and headquarters of Shropshire Council. It is the second largest town in the ceremonial county of Shropshire, after Telford.

Shrewsbury is a historic market town with the town centre having a largely unaltered medieval street plan. The town features over 660 historic listed buildings,[7] including several examples of timber framing from the 15th and 16th century. Shrewsbury Castle, a red sandstone castle fortification, and Shrewsbury Abbey, a former Benedictine monastery, were founded in 1074 and 1083 respectively, by the Norman Earl of Shrewsbury, Roger de Montgomery.[8] The town hosts one of the oldest and largest horticultural events in the country, Shrewsbury Flower Show, and is known for its floral displays, having won various awards since the turn of the 21st century,[9][10] including Britain in Bloom in 2006.[11]

Today, lying 9 miles (14 km) east of the Welsh border, Shrewsbury serves as a cultural and commercial centre for the ceremonial county and a large area of mid-Wales, with retail output alone worth over £299 million per year.[12] There are some light industry and distribution centres, such as Battlefield Enterprise Park, located mainly on the outskirts. The A5 and A49 trunk roads cross near to the town, as do five railway lines at Shrewsbury railway station.

Source: http://en.wikipedia.org/wiki/Shrewsbury