The hard disk drive allows your pc to store data permanently.  All your files and settings will eventually end up on this disk. The disk consists of a number of (read and write) heads and a number of layers (platters).  The head charges the magnetic surface of the platters (that spin very fast ranging from 5400 rpm in laptops to 7200 in avarage desktop pc's).  The same head can read the charge and therefore detirme if a bit is either 0 or 1. After the pc is powered down the charge remains on the hard disk drive and therefore the data will still be avaiable after a reboot (unlike memory).

IDE and S-ATA

Currently there are two different interfaces of interest to the consumer, IDE and S-ATA.  IDE is the "old" standard, using very wide cables.  Most pc's from before 2006 will be equiped with IDE connections on their motherboards. Because a S-ATA disk wil not fit on an IDE motherboard connection (and vice versa) you will have to keep this in mind when purchasing a hard disk drive .  S-ATA is the new standard and uses much smaller cables and has a higher data bandwith.  S-ATA exists is two variants; sata 150 and sata 300. To put it simple; sata150 equals 150 MB/s and Sata300 equals 300MB/ s of data transferrate.  Currently the fastest harddrives have a maximum avarage speed of 100 MB/s, therefore there is no big difference in performance between sata150 and sata300.

Solid State Drive (SSD)

Thanks to a costreduction of the memorychips used by mp3players, compact cameras, mobile phones, etc, hard disk drives without moving parts have been developed. Instead of a moving read and write arm multiple memory chips are placed on a big chip to create a hard drive. Because there is no longer a moving arm retrieving information the low acces time as a result of this technology is the biggest advantage of solid state drives. The biggest disadvantages are the high prices and the limited storage capacity. Currently you will have to pay €180 for 80GB, +/- €450 for 160 GB and a whopping €1500 for 512GB. A traditional hard disk drive with 1TB (1000 GB) is currently for sale for less then €60.

Size:

Currently, hard disk drives for sale from 80 GB to 1500GB.  Usually drives around 500 to 750 GB relatively advantageous to purchase (the price per MB is low while the purchase price remains around 60 euros). This is because a hard disk once a certain amount now costs to produce additional capacity will cost money of course.

Cost analysis (2009):

Please note that prices fluctuate, this is just one example. You can easily create this table for the prices and discs that store on your local area.  You share the price in euros by the size in Gb.  The green bars are relatively favorable discs (the cheapest disk in euros, a normal amount for a drive to spend, and the cheapest disk in price/mb).

Frequently Asked Questions

I lack storage space, can I easily buy an extra hard drive?

A hard disk is one of the most easiest components to install in your desktop computer.  You plug in the power cable and connect the IDE or S-ata cable to both the motherboard and the drive (just matter of clicking together) and the disc will function.  The disk will be recognized in Microsoft Windows automatically.  IDE requires an an additional step that will be explained below.  Hereafter you will need to initialize, format and partition the hard drive before you can actually store data on it.  Again, this is quite simple. An explanation can be found at the bottom of this page . Please pay attention if there already are several disks in the system, depending on your motherboard, you can connect an X number of hard drives.  Often there are 2 IDE ports that each can connect 2 devices (Including devices such as CDrom players etc).  If your motherboard is equiped with sata you will generally be able to connect between 4 to 8 devices. A more detailed explanation can be found here (dutch).

I bought a 250GB Hard Drive but Windows detects far less?

Although one would expect otherwise, 1000 Kilo Byte is not equal to 1 MB, but 1024 KB equals 1 MB (Mega Byte). Since hard drives are measured in GB (Giga Byte) and again 1024 MB = 1 GB a large difference emerges for those that believe 1 MB= 1000 KB. Unfortunately the hard disk drive capacity is listed in Gb which uses the 1000= 1 system. Operating system Windows uses the 1024=1 system. Now it is easy to understand that your hard disk 250 GB harddisk (according to the manufactorer),is reported as 238GB by the operating system.  You did not lose any storage capacity, there is just a difference in the standards for reporting the capacity, just as with kilometers and miles.

Which brand should I chose?

Since the introduction of the Samsung Spinpoint series Samsung has become the most interesting brand. The Samsung  SpinpointF3 1TB hard disk, the follow up from the similarly succesfull Samsung Spinpoint F1, drive is a very fast but affordable disk. (Note the Spinpoint F1 640 GB, 750 GB are not as fast as the Samsung Spinpoint F1 1TB). In addition samsung offers the Spinpoint F2 series, which is labeled eco-green. These drives spin at 5400 rpm rather then 7200 rpm in order to reduce power usage.

Western Digital offers some nice high performing disks such as the WD Caviar Black. Unfortunatly these drives are relatively expensive.  Therefore this hard disk is less suitable for consumers who are not looking for creating a high-end/high performance pc.  Furthermore,  two other drives working together in a raid 0 array will offer superior performance for less money with an even higher storage capacity.  For more information about raid please continue reading the article.

Seagate used to be in this list. Seagate is the largest independent hard disk manufacturer in the world, its drives have a slightly worse performance then than the samsung (but still  higher than the average disk). However Seagate used to be known for its quality which was also reflected in a 5 year warrenty. After the credit crisis this 5 year warrenty is no longer available, in addition there have been firmware issues in the .10, .11 and .12 series of the hard drives (inaccesible hard drives etc) so PcInside can no longer recommended to purchase Seagate hard disk drives.

Performance comparison hard disk drive (benchmark):

(source: http://www.bit-tech.net/hardware/storage/2009/10/06/samsung-spinpoint-f3-1tb-review/5 )

Raid

Raid stands for Redundant Array of Independent disks, this allows data across multiple disks, more than 1 disk to store or a combination thereof.  What does the simpler said several computer disks as if the disk is only 1.

There are a number of interesting raid for the consumer:

• Raid0 - speed
  With RAID0, the data is spread accross 2 (or more) hard drives. Suppose you have a 10MB file and you have 2 hard disks that steel is set to RAID0, then 5MB to one and 5MB disk to another disk to be sent.  The advantage is that there is 2x so quickly, because both discs have only half the work.  Another possible advantage is that the tax per disk goes down the life goes up, this is never good but it proved a logical plausible.  There is also a disadvantage if 1 of the two disks dies then the other data on the disk even more useful, because with only half of a file you nothing more.  The speed advantage is almost always high (often 95% performance) and shortened installation times of huge software (personal experience, with factor 4).  The total storage capacity is equal to that of the two disks, do you have 2 disks of 500GB, you can then use 1000GB.
  
• Raid1 - safety first
  With Raid 1 the data from 2 disks is duplicated. Suppose you have a 10MB file and you have 2 disks in a so-called riad 1 configuration.  The 10MB file will be stored on the first disk and also on the 2nd disk.  This 2nd disk will not be seen in windows.  The advantage of this configuration is that if 1 disk dies the computer at startup recognizes this and will switch on the dates of the other disk.  You can then replace the defective hard disk and the data will again be put on. In theory there is some profit performance possible, research has shown that this is negligible.  This is a solution aimed at safety.  A major disadvantage of this method is that the total storage capacity is as large as 1 single disk. You lose so the storage capacity of 1 full disk.  Suppose you have 2 disks of 500 GB you can only use 500GB.  This is obviously not very cost efficient.  It is therefore cheaper to manually make a backup of your important files on 2 discs to distribute, this course takes more time.  The RAID1 configuration does this automatically.
  
• Raid10 - the best of both but expensive
  Raid10 is a combination of the previous 2 solutions, so you have both speed and extra security.  The disadvantage is that you are not less than 4 hard disks need.  The expensive ones power (15W per hard disk) as compared to the previous double solutions.
  
• Raid 5 - somewhere in between?
  RAID5 is somewhat difficult to explain, shortly by the turn is a middle ground between the raid 0 and 1.  There is hereby normally used 3 disks.  By a parity difficult to explain this configuration system is able to distribute the data as on the 3 disks. If 1 disk is broken then the system data on other disks retrieve it by this calculation.  This comes down to is that there is profit performance as riad 0, it is spread across multiple disks.  The total storage capacity in this system is equal to 2 of the 3 disks.  You're as safe as in the raid 1 configuration but it will cost "only" 1 out of 3 disks of space (33% in this case) instead of 1 of the 2 discs (50%).  Suppose you have 3 drives of 500 GB, you can use 1000GB.
   There is a big but, this system is more than simply spreading information.  There must be performed calculations that time.  Would you come close to the speed with which profit RAID0 / raid10 bidding then you will need to buy so-called raid controller.  Overall, the controllers of the motherboard less suitable for this configuration.  These controllers cost between 50 and 100 euro, that is for the consumer a lot of money.