Hard Drives

The hard disk drive is the long-term storage of your PC. Every time you install a program or save a file, it is being stored on your computer’s hard disk drive.


With programs needing more space I would recommend that you always opt for the largest capacity you can afford to meet your current needs. It must be pointed out that although you can now get an extremely large capacity hard drive in excess of 1 TB (Terabyte) , most data would usually be backed up to CD or DVD.


If you intend to do any graphics or video editing you’ll need a large amount of disk 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 picture albums and the odd game you can easily start using serveral GBs of space. 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.


Their capacity is usually measured in Gigabytes (GB), with 1 Gigabyte being equal to roughly 1000 Megabytes.


Typical modern drives range in size from 40 Gigabytes to 1 Terrabyte (1,000 GB) or above! They also generally come in three speeds, 5400rpm, 7200rpm and 10000rpm. The 7200rpm drives are the most common.


It is still possible to buy small 40-80GB drives for around �30-40, but for just a little more you can purchase a drive with upwards of 200GB.


I would suggest a drive of around 120-160GB 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.


There is a known problem with Hard Drives larger than 137GB when installed on a Windows XP PC without Service Pack 2. Here is a work around without installing additional disk management software (opens in new window).



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.


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 can detect via the mothercboard BIOS.


Serial ATA (SATA) as mentioned already ADE has been around for many years and as a result of other areas of PC architecture evolving has reached a bottleneck for data transfer. SATA with its first standard supports transfer rates measured at SATA 150. Older motherboards supported ATA 100/133, this basically means the rate of peak data transmission per clock cycle (burst rate). So if your hard drive is ATA 100 it has a theoretical burst rate of 100mbps.


This standard will also 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.


For the majority of users this type of thing does not matter, the main point is that you are aware of the different options.



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.


So how big do you need? Well, it depends a lot on what you want to do with your PC. Here are a few typical sizes of files stored on a computer system:


Microsoft Windows 7 – Approx 16GB

Microsoft Windows Vista – Approx 15GB

Microsoft Windows XP – Approx. 1.5GB

Microsoft Office Professional – Approx. 600MB

Modern Type Game – From 500MB to 12GB

An Album of MP3 Music – Approx. 70MB

A letter – Approx. 0.1MB

60 Minutes of Video – Approx. 600MB


So as you can see, even a ‘small’ 40GB hard disk drive can go a long way!