INTRODUCTION
The Hard Disk Drive (HDD) isn't an essential element for the performance of the computer but, obviously, it makes our life easier. In fact, the Hard Disk, unlike RAM memory, is a peripheral which let us store huge amounts of data although our system is switched off. On the other hand, RAM memory is really faster than a Hard drive, so it's the memory used by software to store the data it needs. In short, the hard drive is a permanent, incredibly huge and slow memory while RAM memory is volatile, really fast and not necessarily a big memory.
As we have said, a hard drive is used to store huge amounts of data, so capacity will be the most important feature we will have to consider, but it isn't the only one. It's worth also taking into account performance, power consumption and its interface.
CAPACITY
Capacity has increased really fast in the last few years. Four years ago we spoke about HDD of 250GB and, today, the capacity of a HDD reaches 1 TB (one terabyte) without any difficulty. Although nowadays the price-capacity relation advises us to buy the HDD with the more capacity we find, it's always advisable to consider how much capacity we will need in order to save some money. Money that we could invest in a better processor or in more RAM. For example, a HDD of 500GB could cost about 40€ (60 US $) while a HDD of 1,5TB could cost about 90€ (135 US $). These 50 € of difference would let us buy 2 modules of DDR3 1GB 1333MHZ RAM.
Nevertheless, it will be worth buying a 1,5TB HDD if you download huge amounts of data everyday or if you have a digital camera o a video camera. Then, capacity is never left. In a year, most people typically add at least a few gigabytes of digital pictures, or even more data if video is stored on the drive. Add to that music, new applications, and so on. Unless you don’t touch digital media at all, you might need an additional 50-100 GB capacity per year, and enthusiasts and professionals may easily require far more. Hard drives are very affordable: terabyte drives will soon be at $80. So if you need more storage anyway, go for it.
Interior of a Hard Disk with one platter and the reader head
PERFORMANCE
As we have said before, capacity has quadrupled in the last three-four years. Concerning performance, it has doubled. It's safe to say that each and every hard drive selling today is far superior to older-generation drives, as improving recording technologies keep pushing forward capacities and performance. But no individual feature—even Native Command Queuing or a larger cache—can make as much of a difference as simply stepping up from one drive generation to the next. In fact, the only reason why new hard drives aren’t getting faster to an even greater degree is an increased emphasis on power consumption and drive efficiency.
Therefore, when it comes time to buy a new hard drive, make sure the one you pick is a latest-generation model.
INTERFACE
Besides capacity and performance, other improvements that make the new HDD superior to the older ones are the interface transition from parallel ATA to Serial ATA 150MB/s (and then 300 MB/s). If you decide to buy a SATA or SATA II 300 MB/s, for example, make sure that your motherboard supports this transmission bandwith so as not to waste your money.
Elements of a Hard Drive
OTHER CONSIDERATIONS
I think it's worth having at least 2 HDD in my system because of security reasons for our system and for our data integrity. For example, I have software in one HDD with the OS, and data in the other one. If a virus infects my software HDD (the Hard disk where the OS is) and I eventually have to format it, I won't lose my data. Furthermore, if the two HDD are exactly the same, you can benefit from RAID options.
Two hard disk are also interesting if you like working with two operating systems. For example Linux for working or professional issues and Windows for leisure. Then, you can set up an OS in each drive and chose the OS in the boot menu when you switch on your computer.
Internal elements of a Hard Drive
SUMMARIZING
The following list shows some parameters of a Hard Drive. In my opinion, the key features to consider when buying a Hard drive are in bold:
Capacity: From 250 GB to 1,5TB
Cache: 16 or 32 MB
Interface: SATA/300
Warranty
Form Facto
Spindle Speed
Platters
Power consumption
CONCLUSIONS
Capacity is the most important feature but, in order to save money, I would buy the capacity I think I would need. I also would consider the possibility of buying two Hard Drive because of security reasons. Make sure also that the HDD you pick is a latest-generation model. Finally, brands like samsung, seagate, Western Digital or Hitachi would lead to a similar performance,so brand isn't really important.
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