A hard drive activity light, sometimes called HDD LED, hard drive light, or hard drive activity indicator, is a small LED light that illuminates when data is being read from or written to the hard drive or other built-in storage.
SATA HDD (Hard Disk Drive) Activity LED Indicator for NAS
It is useful to know when your computer's hard drive is being accessed. This will prevent you from having to remove the battery or unplug the computer from the power supply while the operating system is still accessing files on the drive. This can lead to corruption of important files.
On a desktop, this activity light is usually located on the front of the computer case.
On a laptop, the button is usually located near the power button. Sometimes it is next to the keyboard, and sometimes it is on the edge of the computer.
