Articles: Storage

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Watching the never-stopping progress in the performance of central processors, graphics cards and other PC components, I sometimes wonder what component is the slowest to evolve these days. I guess it is the hard disk drive. Yes, the storage capacity of hard disks is getting higher and higher but it seems like the manufacturers are trying to engage the users into the race for gigabytes of storage not because they care so much about them. Rather, it is because increasing the capacity of the HDD has proved to be easier than increasing its performance.

The HDD becomes faster with higher recording density but only in one operation mode: when the disk is accessed for sequentially placed data. Large files are an example of that. As soon as the requested data are not below the magnetic head, the HDD has to take some time to think and move the heads. It takes a dozen or more milliseconds – a whole eternity by today’s standards. It is the delays on the part of the HDD’s mechanics that are the main obstacle to boosting the performance of HDDs. In fact, nothing new has been introduced into the head movement mechanism in the last decade, so why should there be any breakthroughs in terms of performance?

Some time ago one company, which has my respects for its attempts to increase both the capacity and the performance of hard disks (e.g. it was the first to equip desktop HDDs with a large cache buffer), introduced the unconventional product called Raptor. Targeted at desktop PCs, the Raptor combined advanced server-oriented mechanics and an appropriate spindle rotation speed (10,000rpm). The downsides were the small capacity of the disk and the amount of noise it produced. On the other hand, the average time to access data was reduced considerably from about 13 milliseconds to 8 milliseconds. That was a breakthrough indeed.

No other company has followed Western Digital’s example so far (Seagate’s Cheetah NS is not targeted at desktop PCs as is indicated even by its SAS interface). The rest of the manufacturers take no marketing risks and prefer to sell gigabytes as usual.

Solid State Drives are a new fashion on the market of hard drives. The SSD is based on flash memory and has no moving parts. Reading and writing information is performed with flash memory and the process of reading/writing takes only the time necessary to read or rewrite all the cells of the data block the disk controller can work with. The SSD has a low access time because it does not delay much when switching between different cell addresses. The SSD is actually indifferent to the type of access as it performs random-address requests as quickly as requests to sequentially placed data. The SSD is yet too expensive and its capacity is yet too small to replace the traditional HDD but its speed potential is high as you can learn from our review of Samsung’s SSDs.

So what are the ways to increase the performance of hard disk drives? Notwithstanding what I’ve written above, increasing the recording density is a way, too. With higher recording density, there is a higher chance that the necessary data are not too far from the current position of the read/write heads. In other words, the HDD has a higher chance of doing a short seek and the heads won’t have to fly across the entire platter to reach the requested data. A multi-platter design produces a similar effect – there is a higher probability that the requested data are near one of the drive’s heads.

Now I will proceed to the subject of this review, to hard disk drives with a capacity of 1 terabyte. It is the highest storage capacity available today. I don’t try to present them as anything new to you. They have been around for half a year, and the sellers and buyers and, perhaps, repair workshops should have already got used to them.

So, this review comes a little bit too late but only because I wanted to collect a full selection of 1-terabyte drives in it: each manufacturer released both “desktop” and “server” versions of its 1TB drive. Alas, the server-oriented HDDs from Samsung and Western Digital are still missing in this review.

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