Ask CyberGuru

CyberGuru is asked, “I have noticed on my computer I have several hard drives appearing. I know that the C: drive is the main computer’s drive, what is the D: drive used for?”.

During the days of text-based operating systems such as Microsoft Disk Operating System (MS-DOS) the use of drive letters helped us to navigate between drives on computers. In order to select a drive, we would often refer to it by its drive letter.

Modern computers running Windows have their drive letters begin at C: for hard drives. The drive letters A and B were reserved the floppy drives. Over time, as more drives are installed into computers, such as optical (CD and DVD), and USB drives, these are also using drive letters.

The C: drive is often referred to as the system or boot drive, which is used for the Windows as well as important system files and program files. If your computer has a second drive or the D: drive, it is often used stores your data and documents. Sometimes, system manufacturers such as HP and ASUS include Recovery partitions on the D: drive as well.

This drive, depending on your computer set up, may be an actual second physical hard drive (such as a solid state or hard disk drive), or a partition (division) of the first drive.

In addition, if you have a server or Network Attached Storage (NAS) connected, we often map network drives to drive letters also (such as N: drive for NAS or S: for Server) to make it easier to find their contents.

If you have a question you would like to Ask CyberGuru, please contact us.