What does C drive indicates?

Answer 1

The default annotation C: typically refers to the primary hard drive or primary partition of a hard drive from which the operating system is booted. The reason it is typically the C: letter drive is that, back in the day, a 3.5" disk drive was annotated as A: by default and the 5" or floppy drive was annotated as B: by default. The drive letter D: is usually utilized to indicate the default annotation of the primary optical (cd-rom or dvd-rom) drive of the computer.

Due to the creation of hard drive partitions, (or devisions of a hard drive to create virtually separate drives) it is possible for one hard drive to have multiple drive letters typically ascending in letter from E: (Drive C: Primary Hard Drive Drive D: Primary Optical drive. Drives E:, F:, G:, etc secondary hard drives which are also known as slave drives.) Windows is capable of customizing the drive letter annotations to suit the user, (including the primary drive annotation of C:) which is why this is not universal for all computers. However, for Windows, the primary hard drive from which the operating system is booted is always annotated as C: by default. If the drive letter has been changed in the operating system only, a menu will typically pop up on boot up on at least one occasion asking for the drive letter of the hard drive on which the operating system is loaded. (Unless the motherboard settings are changed, the motherboard will automatically try to boot the operating system from drive C:)