Hard Drives are the storage area of your system, where all programs and applications are stored and written to.
With programs needing more space and the PC being used in many areas it is reccomened ed that you always opt for the largest capacity you can afford or to meet your current needs.
If you intend to do any graphics or video editing you'll need a large amount of space to allow the programs to operate smoothly and for the video files to be stored for editing and space to allow the PC to encode any files into smaller edited formats.
The hard drive works in parallel with the memory (RAM) and the motherboard to read and write data through the system.
Operating systems and applications including games requirements for disk space has increased vastly in recent times. An example of this is a typical Windows XP install uses approx 1.5GB of space, a typical PC DVD Game will need just under 5GB.
With your office applications, any MP3 and digital picture librarys and the odd game you can easily start usign serveral GBs of space. This is fine however you should ensure your drives are regualrly backedup or partitioned so you can backup to another location or seperate drive.
If you intend to use your system to backup CD and DVDs you will also need space to ensure that the system can create a temporary file whilst the burning process takes place.
In recent years the hard drive market has benefited from technology advances which allows for larger capacity drives with falling prices. This benefits the users and allows for additional drives to be used either as a main disk or many choosing to add a disk purely for backup purposes.
It is still possible to buy small 20-30GB drives, but for literally £10 more you can purchase a drive with upwards of 60-80GB.
We would suggest a drive of around 120GB for most users as this will allow for plenty of capacity for everyday use and for disk hungry tasks. You can of course divide or partition the drive this allows for backups to be copied from one partition to the other and allows for easier maintenance and organisation of files.
IDE has long been the standard to allow ATA devices to work together in PCs. There have been several different versions of ATA since it was first introduced in the mid 1980's. The most common that we will mention are ATA 33, ATA 66, ATA 100, and ATA 133.
The IDE/ATA standard is the most common interface also known as PATA. There have been several different versions of ATA since it was first introduced in the mid 1980's. They all focus on the theoretical transfer rate via the interface between the drive and the motherboard.
The connectors are a bank of pins which are at risk to damage. Also the configuration in older systems had to be setup via Jumpers or Bridges. More modern systems could detect via the BIOS using the cable select feature.
Serial ATA (SATA) as mentioned already PATA has been around for many years and as a result of other areas of PC architecture evolving so to have a bottleneck for transferring data quicker between the systems buses and the hard drives. SATA with its first standard supports transfer rates measured at 150 in relation to the previous standards.
This standard will allow for faster rates to emerge in coming years.
SATA does away with large ribbon cables and instead uses a thin cable with a small connector which can easily be clipped on to the connector. Bridges have been removed as the drive is automatically detected by the system or separate SCSI card.
Older motherboards supported ATA33/66 the newer motherboards and hard drives support ATA100/133 this basically means the rate of peak data transmission per clock cycle (burst rate). So if your hard drive is ATA100 it has a theoretical burst rate of 100mbps.
For the majority of users this type of thing does not matter, the main point are that you are aware of the different options and can relate the information to the indicators on the hard drive casing or the motherboard manual.
Another value which is referred to is the speed of the actual drive. Older drives were typically 5400RPM newer versions were introduced and the default standard is now 7200RPM this means the amount of revolutions per minute. Faster drives using SCSI or SATA can reach speeds over 10000RPM when comparing drives you should look for the seek and access times this are measure in milliseconds and tell you how fast they can access or write data to or from the drive.
A drives buffer is an amount of memory (RAM) built-in to the drive which is used to store data that is accessed frequently. The larger the buffer the more data that can be stored which reduces the operations which take longer to be read and then wrote from the drive. The default buffer size is 2MB although many makers have increased this to 8MB and no doubt this will increase as the drive market continues to increase in capacity and performance.