Is it disk or disc? When talking about storage media, one often encounters these two variations for spelling of the same word. Is there a difference between the two? What is the correct spelling? In fact, there is a difference and each spelling refers to different types of storage media. This is examined in more detail below.
When it comes to optical storage media such as CDs, DVDs, and Blu-rays, the accepted and always used spelling is OPTICAL DISC. This type of storage media is read with light or to be more specific laser light and therefore, this can be the distinction for when to spell disc with a “c” instead of with a “k”.
However, there are some exceptions of course. For example, DVD-RAM optical storage media are usually spelled as DVD-RAM DISCS (because they are read with light) but the spelling can also be DVD-RAM DISKS. This is likely because these types of optical storage media function more like hard drives in some ways than optical discs. LASERDISCS (LDs) is the normal spelling for those large format discs used for storing videos and movies and the precursors to DVDs. However, sometimes you will find them spelled as LASERDISKS. For Magneto-optical (MO) storage media, the normal spelling is Magneto-optical DISKS, but once again, sometimes you will find them referred to as Magneto-optical DISCS as well.
For magnetic storage media, the reading device is a magnetic head, instead of laser light, as is the case for optical discs. Therefore, for these types of storage media, the spelling is MAGNETIC DISKS. There are two types of magnetic disks. Floppy disks, which are removable and low capacity storage formats, commonly found in 5.25 and 3.5-inch sizes. Floppy disks can also be referred to as floppy diskettes or simply diskettes. Hard drives are storage media that contain magnetic disks of various sizes, along with various mechanical components for the functioning of the hard drive, inside of a sealed protective housing. A hard disk drives can be found inside of a desktop or laptop computer or can used as an external storage device with connection to a computer via a USB port. There are really no exceptions for this type of media. If read with magnetic heads, then circular magnetic media is referred to as a DISK.
Therefore, to summarize when to use disk or disc – optical storage media that are read with laser light such as CDs, DVDs, Blu-rays, DVD-RAMs, and LDs, are almost always spelled as DISC with a few minor exceptions; Magneto-optical media is spelled as MO DISKS; media read with magnetic heads such as floppy disks and hard disk drives, are always spelled as DISK.