Drive Name

While booting, your computer can detect the number of drives present in the computer. The drive names are assigned as A,B,C,D and so on. If your computer has two floppy drives and one hard disk drive, they are identified as :
First floppy drive : A Drive
Second floppy drive : B Drive
Hard disk drive : C drive
MS-DOS normally reserves one drive more than the number of drives physically present. For example, if a computer has 3 drives as described above A,B and C, the letter D is reserved for next drive.

Default Drive :
The condition given or assumed by a system is called its default. Similarly, the drive which is used to  load the system is known as default drive.
For example : if you use hard disk (C: drive) to load the lotus 1-2-3, the C: drive will be the default drive.

Prompt :
The constant message that you will get while working on the computer is referred as prompt. If you boot your computer using floppy disk in drive A : , you will get A>, or if you have hard disk to boot your computer, you will get C>. The symbols A> or C> are called prompts.
You may see slightly different symbols as prompts, such as A:\> or C:\>. You can also customize your prompts by putting other symbols or text.