Index
Introduction
Storage Capacity
Speed
Interface
Optimising Pricerunner
Conclusion

Introduction
The hard disk drive constitutes one of the most critical components of your PC. It’s here that you install the Operating System, and various programs that help you optimize your PC. In addition to this, it’s on the hard disk that you store your files, music, movies, etc. The hard disk as a storage medium offers you an unparallel advantage of speed, size and permanence, over other mediums like CD-ROM’s, tape drives, ZIP drives, etc. This means that you have the benefit of a high storage capacity from 20GB to 1000GB as well as faster data retrieval in the form of high RPM or revolutions per minute. As with most technologies, hard disks have seen an exponential growth over the past few years in terms of storage capacity, interface, and retrieval speeds. No longer are hard disks expected to be housed within the computer, but can also be used as an external device, connected to the PC via USB or FireWire ports.

Storage Capacity
Currently, the most basic hard disk capacity starts at 20GB. With this space, a user can just about manage to install the latest version of Windows, office applications and any other programs that they are using. If a user has a requirement for creating or editing graphic images using any popular editing software such as Adobe Photoshop or the more advanced 3D Studio Max, then they must look towards a hard disk capacity of over 250 GB, or use multiple hard disks. On checking the various prices of hard disks available in the market, one can safely say that price/performance can be best optimized on the purchase of a hard disk with the maximum capacity. This allows the user to make a one-time purchase of the hard disk as well as avoid the troubles associated with constant upgrade due to lack of space. As new file formats allow users to store music, images, video, etc without loss in resolution or sound quality, the storage capacity of the hard disk needs to be intelligently decided upon before time of purchase.

Speed
The first impact of the speed of the hard disk installed in the PC, is when a user experiences his machine booting-up. The speed of the hard disk is in direct relation with the machine start-up. The higher the rpm’s of the hard disk, the quicker the machine boots-up the operating system. A hard disk constitutes of one or more platters of metal or ceramic disks coated with a magnetic film. This is where data is stored. With the aid of a magnetic read/write head located on an arm, which floats over the metallic platters as they spin at thousands of revolutions per minute, data can be stored or retrieved. Revolutions per minute or RPM’s are the benchmark, which a user needs to look at to estimate the speed of the hard disk. As storage capacity increases, data read rates to the order of 10 megabytes per second and data latency of 10 milliseconds are commonly found. Users can find hard disks with 4200 rpm reaching up to 10000 rpm, while most hard disks are optimized to function at 7200 rpm.

Interface
Coupled with speed, the interface that the hard disk uses to connect to the motherboard is equally important for determining its effectiveness. The interface is the channel of communication that enables data flow that is written to or read from the hard disk. Currently, hard disks are connected to the motherboard via two primary interfaces, IDE and SCSI. Integrated Drive Electronics-IDE interfaces are most commonly used in most of the hard disks sold, while Small Computer System Interface-SCSI is targeted at the high-end user.

Integrated Drive Electronics (IDE) / Advance Technology Attachment (ATA) This is the most basic interface for various storage devices such as hard disk drives and CD-ROM drives available in the market. This technology works with computers that are based on the Peripheral Component Interconnect (PCI) architecture. Based on this technology, the controller is integrated onto the hard disk drive or CD-ROM drive, thus enabling transfer of data from the microprocessor to the storage device and vice versa. IDE is used mostly in conjunction with the Advance Technology Attachment or ATA. There are various versions of ATA such as ATA-3, Ultra-ATA, ATA/66, ATA/100, but all these versions are essentially aimed at increasing the data transfer speed between the storage device and the microprocessor. ATA/100 currently enables data transfer rates of 100Mbps.

Small Computer System Interface (SCSI) This interface technology finds its roots in various Unix-based systems, which Apple later incorporated in its range of computers. Although a much better interface, since SCSI was not part of the mainstream technology such as IDE, which was being incorporated on PC’s, it was relatively unknown to the common computer user. SCSI interfaces provide faster data transmission rates of up to 80 Megabytes per second and enable multiple devices to be connected to a single port, thus increasing its functioning from a mere interface to an Input/Output bus. Various versions of this technology such as Fast SCSI, Wide SCSI, Wide Ultra 2 SCSI, are targeted at the serious computer user, which offers various data transfer speeds. SCSI based hard disk are a bit more expensive than IDE based ones, and is the ideal purchase of a serious computer user, as it offers much more speed and stability than IDE.

Redundant Array of Inexpensive Disks (RAID) Hard disks based on this technology are targeted at enabling high-end computing for mission critical functions. Most RAID based devices are found in servers, which need to offer real time data access to the user. To simplify RAID, it uses two or more than two hard disks in storing data on the server. If either one of the hard disk fails, the other one acts as a real time backup for the data, thus offering a seamless real time access to the user. This technology has various levels and some data storage companies such as EMC have developed their own proprietary technology based on this standard. The common computer user will not be able to optimize this technology and thus this will remain a purview of the IT department.

Optimising Pricerunner
Trying to narrow down your search for a Hard Disk that is apt for your computer, Pricerunner offers various search parameters on Name, Price, Interface, Internal/External, Storage Capacity, Size, Revolutions per minute (RPM), and Access Time. The easiest way for an effective search is to look at the Interface and Storage Capacity fields as they will determine the range of drives to choose from. While Price will definitely pay a role in narrowing down to the right product, the hard drives compatibility with your existing computer as well as its capacity will be the primary search parameters.

Conclusion
In order to make the right choice in the type of hard disk required for your machine, determine its usage and then make the purchase. If you are not a heavy computer user and need to change the hard disk for your home PC, then buying any drive which is IDE based and gives you the maximum storage for your money is the right choice. For Unix and Apple based machines SCSI are the de-facto choice, while RAID based devices are targeted at the System Administrator and the IT department.

For comments or suggestions please write Jamsheed Gandhi