Hard disk storage - completely full and never enough

According to Data Recovery London -Labs , External Hard Disk Drives provide great flexible storage option and security by providing a mobile back upoption, yet this advantage has dangerous twist to users.

With storage capacity running in hundreds of Gigabites, with high rates of data transfer, in addition to the flexibility to plug the external drive to a Laptop , Desktop, Server , Memory cards , Camera or iPod and sold at reasonable prices have increased their popularity dramatically.
However, as the popularity of the external drives containing backups and valuable data are increasingly to accomodate the bigger Music & Photo files emerging from Apple-Mac sytems. External drives are failing for no apparent reasons. Majority of these failing drives are often of well known commercial brands such as Lacie, Freecom and Omega and with the latest high capacity Maxtor, Seagate or Western Digital hard disk drives models with storage capacity exceeding 320Gb or even 400Gb on a single drive.
According to a study of 100,000 drives conducted by Carnegie Mellon University, it is widely believed Hard Disk Drive vendors manipulate the (MTTF) - mean time to failure. In fact The mean time to failure (MTTF) of drives, according to their manufacturers, vary from 1,000,000 to 1,500,000 hours, suggesting a nominal annual failure rate of at most 0.88%.
Whereas the study finds that "up to 13% observed on some systems.". This suggests that field replacement is a fairly different process than one might predict based on datasheet MTTF.
It has also been established that failure rate is not constant with age, and that, rather than a significant infant mortality effect, evidently a significant early onset of wear-out degradation. That is, replacement rates in research data grew constantly with age, an effect often assumed not to set in until after a nominal lifetime of 5 years. The study, also carefully point out that the study didn't necessarily track actual drive failures, but cases in which a customer decided a drive had failed and needed replacement. The study also explains that no vendor-specific failure information, and that his goal is not "choosing the best and the worst vendors" but to help them to improve drive design and testing.
Also, little difference in replacement rates between SCSI, FC and SATA drives, potentially an indication that disk-independent factors, such as operating conditions, affect replacement rates more than component specific factors. On the other hand, we see only one instance of a customer rejecting an entire population of disks as a bad batch, in this case because of media error rates, and this instance involved SATA disks.
Time between replacements, a proxy for time between failure, is not well modelled by an exponential distribution and exhibits significant levels of correlation, including autocorrelation and long-range dependence.
Generally, inside the slick casings, often are poorly ventilated or even not ventilated at all, external hard drives assemblers include the cheapest available drives such as Maxtor & Seagate, combined with badly ventilated enclosure casing, the combination is catastrophic for any given user, especially when the hard disk drive is of high capacity containing crucial back-up data
For any given Lacie with multiple drives, this can be a terrible experience with RAID drives and data in excess of 1 terabite. Often with RAID array external drives, the drive failure are more frequent and the damage is more extensive than single drives. According to Haj Majed Aziz of UniRecovery – RAID 5 Data Recovery Labs “many of the 1 terabyte LaCie external drives contain 250Gb Maxtor IDE in RAID array, inside badly ventilated enclosures, when used on regular basis, especially within office environment, they are utter disaster.”
Hitachi has unveiled a drive which has reached the new heights of one terabyte (TB). Its drive looks like any other, but uses perpendicular magnetic recording to make space for all that data.
The current technology generation of LRT-Longitudinal Recording Technology, which records the bits laying horizontally, has been superseded by the recording of the bits standing vertically. However the cost is in the region of $18,000 !

Great articles, both are very educating. However, would you care to indicate the drive you would recomend to buy.
Thanks

visit http://www.unirecovery.co.uk

If you find that your hard drive is clicking, the first and foremost thing you must do is shut down your system to prevent further damage. This will reduce the chances of permanent damage and will also reduce the risk of making your data unrecoverable. If the hard drive is clicking, making grinding/scraping or whirring sounds, the BIOS does not recognize and accept the drive; external hard drive, laptop or system or was jarred or dropped; the computer was exposed to water or fire/smoke damage. When a hard drive is exposed to any of these things, it will result in physical and internal damage to the read/write head of the hard drive and/or the platters. Therefore the opinion of a Data Recovery Specialist is vital in this scenario.

When the hard drive is in action, the read/write heads do not rest on the platters. During operating, the heads ride on a micro-cushion of air that prevents it from making any physical contact with the surface of the platters. When the head of the hard drive begins scratching the platters, it results in loss of information. This is known as clicking. If you try to keeping switching off and booting your computer again and again, you are causing more damage and this can result in permanent data loss. A clicking hard drive is a very serious symptom of hard drive crash and must be taken seriously.

The best thing to do when your hard drive crashes is to switch off the system and not boot it up again. Keep it switched off and let a professional technician deal with it. Sometimes disassembly of the hard drive is required in order to recover data. It depends on the extent of the damage to the hard drive. In clean room environment, the covers and seals are removed from the hard drive so that technicians can work on or replace internal parts while maintaining the warranties.

The technician first begins by identifying the problem and replacing problem causing internal parts like read/write heads, re-writing firmware, performing platter swaps, recalibrating and realigning file structures and restoring as much of the data as possible. Hard drives that click generally go a clean environment room where they are disassembled and the individual components are checked for scratching, scoring, correct calibration, ohm reading and failed chips. ROM chips and firmware is also checking. The spindle motor will be tested for proper rotations, speed, alignment and frozen or damaged bearings. Mechanisms that can identify the damaged are used to test the hard drive for overwriting and damage. Faulty parts are replaced and new firmware is installed. When the hard drive is brought to a ready state, the raw image is created sector by sector. After the imaging process, data is recovered, critical files are checked for damage and integrity and the data is saved to a new physical location like an external hard drive.
If the hard drive is not suffering from any severe mechanical or electrical failure then it is sent to a cloning room where bit by bit and sector by sector raw images are created. Once an image of the hard drive is obtained, it is read to make sure the files are not corrupt and the critical files and folders are recovered and copied onto a new physical location. Imaging can take anywhere between 2 to 16 hours depending on the extremity of data loss and the size of the hard drive.
Hard drive Data Recovery depends on the severity of damage and failure. It is best to keep regular backups of important files and folders to avoid complications due to a hard drive crash. Always make sure you handle an external hard drive carefully and do not hit your computer if it hangs – the hard drive just might crash due to the force!