Hard Drives



Hard drives are an essential feature of any computer or laptop. They act as primary storage devices because of their huge capacities as well as random data access. The commonly available hard disks have capacities ranging from 80 GB to a whopping 1 TB. Hard disks are not a new technology. They were invented about half a century ago. But until now, no other device has been able to match them in terms of performance, capacity and cost.

Though hard disks are built as rugged as possible by their manufacturers, there is always a possibility of their crash. In this, the read / write head that is hovering just above the rapidly spinning platters comes crashing down on the data-recording surface, thus leading to data loss. This is a very serious situation that requires the disk to be taken to a professional data-recovery company for repairs or extraction of data.

Optical Disks

Optical disks are currently the standard removable data storage media used by computer users. The disks are quite thin and can easily fit over your palm. They are made of tough polycarbonate plastic that is very hard to destroy. The disks are used in tandem with an optical drive that has a read / write head. The latter emits a laser that actually records the data on the disks by etching a pattern of pits in a circular groove. The groove begins from the finger hole in the centre of the disk and goes around in a tight circle, working its way toward the edges.

Optical disks are of two types: CDs and DVDs. The former were the earliest optical drives to be introduced in the market. These are currently amongst the cheapest storage media available in the market and can store a whopping 700 MB of data. Some years ago, the latest version of optical disks was introduced. The DVDs have a staggering storage capacity of about 4.6 GB. They can easily hold a full-fledged Hollywood movie. Though optical disks can safely store your data for up to ten years, their data-recording surface is exposed to the elements. Care has to be taken to protect it from surface contaminants such as dust, stains and scratches.

Tape Drives

Tape drives are based on a very old but tried and trusted technology. They work the same way as audio cassettes are used to record music. Tape drive systems have two parts ? the drive and cassettes. The latter comprise of a long but thin and narrow length of tape wound around a couple of spools. The entire assembly resides inside a tough plastic case that protects the tape from dust and damage.

The drive has a stationary read-and-write head carrying an electromagnet. The tape moves forward or backward brushing past the head as data gets written or modified. Tape drives can have capacities of anywhere from 80 GB to 500 GB. Their only drawback is that they offer sequential data access, unlike hard drives which offer random access. However, tape drives are ideal for long-term archival storage of data due to their low cost.

USB Drives

Universal Serial Bus (USB) drives are the latest technology to be introduced in the data storage market. These drives have some phenomenal advantages over other media. They are quite small in size, so much so that they are also referred to as key chain or thumb drives. They have no moving parts. Data is stored electronically, not magnetically, on a circuit board that is built around flash memory.

USB drives use very less energy compared to a hard disk or optical disk drive. This makes large-capacity USB drives an ideal replacement for laptop hard disks where conserving battery power is a priority. These drives are independent devices which do not need a separate assembly built into the computer. You just plug them directly into the USB port and they are ready for action. Unlike hard disks, USB drives are totally immune to strong magnetic fields. They are enclosed within a strong plastic case, and thus can withstand impact trauma much better.

This is a very promising technology that is already being touted as a replacement for computer hard drives in the near future. The only problem is that USB drives are currently somewhat expensive. But as the technology matures and prices drop with mass production, they will emerge as a very potent threat for the hard drive industry.