A computer can have both firmware and software. The firmware is permanently stored in the computer, such as the BIOS, and cannot be easily changed or added to. Software, even the OS, can be replaced by reformatting the hard drive. Software includes the applications that a person operating a computer sees, like a web browser or a word processor. Sometimes a device driver is called firmware, since it is needed to run that piece of hardware, like a printer or a video card. The device driver is on the main part of the computer and can be easily updated (if an update exists).