Available types of external hard drives

Deciding on which type of external hard drive to buy largely depends on the intended usage. There are three main types of external hard drives:

• Stand alone – 3.5 inch
  These hard drives are rather large and can be permanently attached to your PC. They are generally used as an extension to the existing storage of the main PC. Stand alone external hard drives offer a very large storage capacity, some in excess of 1TB. These external HDs are built upon standard 3.5 inch harddrives found in desktop PCs and MACs.
• Portable – 2.5 inch
  These external HDs are much smaller in size and also in capacity. They are ideal for backing up information from your laptop or desktop PC. Because they are smaller, they generally have a lower storage capacity than stand alone hard drives. A nice feature to look for in portable hard drives are USB powered drives, which lets you use the drive without having to connect an extra power adaptor.
• Network – NAS harddrives
  NAS = Network Attached Storage. If you have a network of PCs, an external hard drive can be connected to the network so that information can be saved onto it from all the computers. We will not go into this type of external hard drives in this guide.

Important specifications

After deciding on the type of external hard drive to buy, consider the following specifications during your external hard drive reviews.

• • Connection
  There are 4 main ways in which to connect an external hard drive to a computer. The most common connection is through a USB (USB 2) port as it is compatible with most computers. Alternatively it may be possible to connect using a FireWire; Ethernet (network) or eSATA connection. Before buying an external hard drive always check that the connections are compatible with your system.
• • File format
  External hard drives come with either a FAT32 or NTFS file format. FAT32 is the most common and has a maximum file size of 4GB, while NTFS allows for larger files to be saved. NTFS is not compatible with Apple Macs and therefore if you need to save files greater than 4GBto a Mac, look for a HFS external drive file format. Most external hard drives come preformatted with FAT32 which becomes a problem when you try to save larger files to the disk. Therefore we recommend you to always start by formatting the disk in the NTFS file format.
• • Storage capacity
  Depending on the type of external hard drive, it is possible to purchase cheap portable external hard drives with as little as 120GB storage capacity, or alternatively an expensive large storage hard drives with storage capacities of over 1TB (1000GB).
• • RPM and seek time
  Depending on the type of external hard drive, it is possible to purchase cheap portable external hard drives with as little as 120GB storage capacity, or alternatively an expensive large storage hard drives with storage capacities of over 1TB (1000GB).
• • Storage capacity
  This is the speed at which the spindle, which holds the disk, spins while the drive’s heads locate the data. The seek time, measured in milliseconds, indicates how long it will take to get the data. You should look for disks with a RPM of 7200 or higher.
• • Buffer size
  Data isn’t written directly to the hard drive as there needs to be a consistent stream of data during the write function, so instead it is cached to a buffer before being saved onto the disk. The larger the buffer size, the better the performance. 16MB is standard nowadays in most disks.

It is also important to note that while external hard drives are compatible with most operating systems, older computers using Windows 98 or older may need additional software to enable the use of an external hard drive.

Entry level budget

There are some incredibly reasonably priced external hard drives offering up to 160GB storage for under $100.

A good entry level “stand alone” external hard drive is the Western Digital My Book Essential Edition. It offers a storage capacity of 320GB; connects to a PC via a USB cable; has a spindle speed of 7,200rpm and an average seek time of 8.9ms.

“Portable” 2.5 inch HDs we recommend are the Maxtor OneTouch 4 Mini and the Iomega eGo and Western Digital Passport drives.

Generally speaking, entry level external hard drives won’t have the fastest seek times, but they are great to use as backup for your personal computer files.

Medium budget

For better performance and the ability to share data between PCs using different operating systems, expect to spend between $100 and $200.

The award winning Maxtor One Touch 4 Mini 250GB external hard drive, has received great expert reviews with an average score of 87%. This small, portable device offers excellent data transfer rates and is compatible with both PCs and Apple Macs. It is available for around $140.

Advanced buyers

For large amounts of storage and supreme performance, external hard drives of 1TB or more are available for over $200.

The Western Digital My Book Mirror Edition connects to the PC via USB and has a 2TB storage capacity. It supports RAID; offers excellent read/write speeds and even has the ability to encrypt backups. Priced at over $300, its included features still make it good value for money. Read the expert reviews at www.testseek.com.

Final Words

Once you have decided on the type of external harddive you are looking for, we recommend you to use TestSeek.com to find out which products have received best scores in expert reviews from all around the world.

Disclaimer: This guide was written in late 2008 and the specific product recommendations may be outdated. However the basic discussions in this buyer's guide may still be of great value.

Written by; TestSeek staff