You would think that having a multi-gigabyte hard drive should be more than enough to hold all my files. But it hasn't been. While I can try delaying the inevitable by deleting batches of files as I butt up against the "this disk is full" message, buying a replacement or another hard drive becomes an eventual necessity.

Buying a hard drive is not simply a matter of determining what size to get. First, there is the issue of compatibility. Most computers are designed to support Integrated Drive Electronics (IDE) drives, with enhanced IDE (EIDE) drives being the latest version. If you need a really fast hard drive, which will let you save or open programs and files more quickly, look for a Small Computer System Interface (SCSI) hard drive. Keep in mind that if your computer doesn't currently support a SCSI connection, you'll need to make sure your computer can hold a SCSI card and then shell out $50 to $200 or so more for one.

Then there is the issue of performance. You want a drive that can quickly scan the disk for data. Two specs that affect drive performance are rotational speed and access time. Seek a hard drive with a minimum rotational speed of 7,200 revolutions per minute and with an access time of less than 10 milliseconds. You should also look for a drive that supports the fastest data transfer rate that your computer system can handle. With this kind of drive, there should be little to no noticeable lag when opening or closing programs or files.

There is also the question of space. If you're adding a hard drive, make sure there is room inside the computer to hold the device, and that there is an extra power connector for that drive. And while you're checking for available slots, you should see whether a 3.5 inch or 5.25 inch model will fit since these slots come in different sizes. If there is no room in your computer case, you'll need to get an external hard drive, which will come in a self-contained plastic case.

You should buy a drive that can store at least 10 GB of data. When it comes time to install the drive, make sure to have it partitioned, which breaks up the total capacity into smaller chunks for easier storage management. So, rather than one 20 GB hard drive volume, you could have three hard drive volumes that total 20 GB in size. It also allows you to store more files because the drive is formatted more efficiently.