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Digital vaults
The art of storing data safely, maintaining integrity and being able to access it in a speedy manner is more than just sticking a hard drive into your machine. While the number of manufacturers continues to fall, the pace of development ceases to slow down. Now there are more options than ever before for users to store a seemingly unlimited amount of information.

Traditional 3.5" drives are not only increasing in capacity but power consumption efficiency too. Notebook orientated units are becoming fast enough to compete with low-end desktop offerings and solid-state drives are also starting to become affordable. In the past year distributed storage has also gained traction, not only in the datacenter but in the home with relatively inexpensive network attached storage, NAS, devices becoming affordable.

Green gigabytes

In the world of storage, new trends don't often occur. So when Western Digital decided to release their Green Power series of drives it looked like one of the industries biggest players had finally turned away from the performance vector to differentiate drives. The problem is in most systems today, the relative performance gulf between performance in other components and hard drives is getting larger and larger.

Hitachi was the first to introduce the headline grabbing 1 terabyte (1000 gigabyte) hard drive. Other manufacturers followed but Western Digital, instead of going for the speed crown went for a slower but more energy efficient unit at the same capacity. They managed this by tweaking not only the software that controls the hard drive but by making it spin almost 30% slower. Journalists were quick to catch onto this but still praised Western Digital for providing a drive that was clearly prudent with power and yet managed to provide adequate levels of performance for the majority of users. However according to Larry Swezey, Director of Marketing, Hitachi Global Storage Technologies, OEMs just aren't willing to put drives which spin at 5,400 RPM in systems. It's easy to understand. For the majority of people, the power usage from their desktop isn't such a big issue and the speed gain is worth the extra power consumption. For enthusiasts, any gains saved on “green” hard drives can be easily wiped off by installing any of the latest batch of video cards in single or multi-unit confirguration.

If you're really interested in saving the world there's two options left for you. Solid state drives, which have no moving parts at all or notebook hard drives. Using notebook orientated hard drives in desktop systems may sound a curious notion but this writer has been doing exactly that for the past year with little problems. Most notebooks use hard drives which are in the 2.5" form factor. Smaller 1.8" drives are available but Larry will be the first to admit at that form factor, performance suffers greatly (just ask any IBM Thinkpad X series user). With capacity of 2.5" drives now hitting 500Gb, companies such as Hitachi can offer acceptable performance levels for the majority of users on the desktop. Even when run 24/7 these units are providing to be reliable with the four units in our lab able to withstand such a punishment for the past 12 months.

More impressive than outright capacity is the data density manufacturers are hitting. The latest desktop orientated drives can fit around 330Gb of data into a single “platter”. Data density not only means more data on fewer platters, decreased power usage and increased throughput at the same spin speed. However when asked whether drives which pack a greater capacity can compete with smaller drives which spin the platters at higher revolutions Larry’s answer was two fold. There’s no shying away from the physics, the more data you fit onto a platter the amount of data that can be read in one rotation increases. Therefore drives such as Hitachi’s 7,200 RPM 1 terabyte unit can look favourable against Western Digital’s 10,000 RPM 150Gb unit. The problem is that higher spin speeds mean lower latency which is vital for servers where data retrieval needs to be at it’s snappiest.

Weaning onto solid

The biggest development in the past year has been the growing availability and affordability of solid state devices. These are based on flash memory, similar to that found in USB memory drives, digital cameras or mobile phones. While this memory technology has been around for a very long time, only recently has it become affordable to have 20-30Gb of flash memory in a hard drive sized form factor. The lack of moving parts means that not only is energy consumption reduced but latency, the time it takes for you to request the data to it being retrieved, is greatly lowered. Larry remained cool on whether he thought this technology would over-take mechanical mediums but insisted that currently the price-performance-capacity lead held by traditional hard drives will be hard to beat.

A middle ground does exist, one which marries mechanical economy to flash based speed. The use of extra large caches in order to speed up traditional hard drives has been floated but according to Larry the gains are simply not worth it.

The problem is purely a price one. For the amount of cache required to make a sizable increase in performance, the price per gigabyte will simply be too high says Larry. With questionable gains in energy efficiency, due to the platter remaining, the hybrid system doesn’t look too favourable at this point.

Spin city

Larry talked candidly about what his company are doing to make themselves heard in the cut-throat market of desktop and enterprise storage. Hitachi became a big player in the storage market when they bought the then beleaguered IBM storage division. Once the darling of the storage world, IBM were left reeling after the disaster that was their GXP75/60 series drives, nicknamed Deathstars. Larry, rather than shying away from that dark time was quick to use it as an example of what should not happen. A survivor from the IBM camp, Larry worked hard to convince OEMs that such a problem won't occur with Hitachi drives, claiming that his drives top reliability surveys. The fact is few customers will seek solace in surveys when their drive has gone up the spout, but Larry was quick to back up the industry as a whole saying that standards throughout the board are much higher than they were five years ago.

However failure may not be the fault of the user or the manufacturer. Apart from cooling equipment, hard drives are the thing in a computer which physically moves. Up to five "heads" move less than a millimetre above a plate which is rotating many thousands of times a minute. It isn't all that surprising that occasionally things go wrong. Most experts believe that the majority of hard drive failures can be attributed to two things, poor handling while in transit and lack of adequate cooling. The latter can cause the platters to expand under the heat generated by spinning at such high velocity and to make contact with the head. These catastrophic failures usually lead to almost complete data loss. Of course the advice is to backup your data, but it's also advised to always stay within the speed limits and how often do you do that?

It keeps you running

An upshot of the problems faced by IBM's late GXP drives was the recommendation that standard desktop drives should not be run in a system which was always on. For such systems manufacturers came out with drives which apparently are made for such duty cycles. Western Digital call their units RAID Edition, with Seagate its ES and Hitachi use the Ultrastar brand (coined by IBM). Some cynicism has always remained as to whether these units are just a way for manufacturers, who have to compete with very tight margins in the OEM sector, to swindle money from consumers or whether they really are cherry picked units.

These "enterprise" drives are typically found in low-end servers and large data libraries. They embrace the capacity found desktop drives but leverage the apparent reliability of true enterprise SCSI drives of old. What was interesting is the admission by Larry that Hitachi's enterprise drives are physically the same units found in their standard desktop fare. However the Ultrastar units are tested far more rigorously and contain special firmware which is orientated towards workloads found in workstations and small enterprise servers.

Hard drive manufacturers such as Hitachi are facing the same challenges as before but with shorter deadlines as we our storage requirements grow. High-definition media being stored on hard drives will not only increase the capacity required but will demand greater reliability than ever before. The need for carrying more data on the move may actually decrease over time as wireless Internet connectivity increases in both availability and speed. However in the short term, the greatest challenge for drive manufacturers remain how to increase the amount of data that can be stored in the smallest possible space.