Answer:
Magnetic particles on a hard disk.
Step-by-step explanation:
Computer storage devices are permanent storage devices used to store large data for a long time. Unlike the memory in Computers, it is not volatile ( lost when power goes off). There are different types of storage devices and different forms for which they store data.
The types of storage are Optical storage like CD and DVD, magnetic storage as in hard disk drive ( HDD) and solid state drive (SSD), and holographic storage devices.
The optical disk uses dark and white light to represent data in its disk, while the magnetic disk represent data with the positive and negative values. But the holographic storage uses light refractions at different angles.