There are several interface types on the market today. Unless you are buying a new computer, you simply need whatever your computer supports. Whether you are buying an internal or external hard drive, there are some things that you should pay attention to when making your decision.
** Depending on what you have on your hard drive, you may need more space. Digital imaging, graphic design, video editing, and high definition games and videos will all eat up your computers space. Newer computers usually come with at least 100 GB of memory.
** Internal and external hard drives have broken the 1 TB (Terrabyte) barrier and you can now buy a 1.5 TB hard drive for under $150.
** If you only have one hard drive on your PC, you may get another since most PCs will support two hard drives minimum. This also means that you can get two lower-capacity hard drives instead of one very large one, which will cost more in the end. Just be sure to check that your case has space for an extra internal drive.
** Disk seek time and rotational speed both significantly affect disk performance.
** Revolutions per minute will usually determine how quickly your system can retreive and copy information. However, sometimes a higher rpm doesn't mean it is faster.
** A drive with 7200-rpm is probably fast enough for most. The slower 5400-rpm drives still exist, but are hard to find.
* '''Buffer Memory'''
** This is another speed measurement. It allows your computer to set aside some extra room for simultaneous processing. It is basically what helps your computer think ahead.
** The range can be as low as 2MB but as high as 64MB, which is usually better for running big applications.
* '''ATA Interface'''
** Out with the old parallel ports and in with the new serial ports. Whichever way you decide to go, just be certain that your computer has that type of port to support the hard drive.
Internal vs. External
The first consideration is probably whether or not you are up to installing an internal hard drive. Savvy PC people can get a bare drive. Otherwise, there are internal hard drive kits available with plenty of instructions, mounting hardware, and cables. If you are planning to go for this type of internal installment, always double check to make sure that your hard drive case has a free hard drive bay. However, if you aren't exactly known for your techie skills, external drives can be handy and simple to install drives that are also portable.
Internal Hard Drives
Internal Drive Interface Types
* ATA: An older technology, but it still works.
* Serial ATA (SATA): The new ATA type technology, which works well with a high performance.
* SCSI: SCSI is a mature, high performance server class drive interface, yet it tends to be expensive.
There is some controversy over the reliability of SCSI vs. SATA drives. SCSI drives have MTBF ratings based on 24x7 duty cycles. The MTBF ratings for SATA and ATA drives are not based on that duty cycle, and thus not directly comparable. In general, for home use, SATA and ATA work fine.
External Hard Drives and Enclosures
There are two ways to get an external hard drive. You can buy a complete one, like the LACIE Neil Paulton Hard Drive, or you can buy a regular hard drive and put it in an enclosure; this includes all of the plugs, drivers, and connections that you need to sync it to your computer. Most external hard drives connect via USB cable.
External Drive Interface Types
* USB: USB is an external disk connection interface common on PCs and Mac computers.
* Firewire: Firewire is an IEEE standard interface type supported by Apple Macintosh computers. It is faster than USB.