In computer storage, disk buffer (often ambiguously called disk cache or cache buffer) is the embedded memory in a hard disk drive (HDD) or solid state drive (SSD) acting as a buffer between the rest of the computer and the physical hard disk platter or flash memory that is used for storage.

The hard drive cache is called a ‘buffer’ by some, as it is a literal buffer that works on your hard drive disk. Basically, it tries to serve and use temporary memory for your hard drive, as it simultaneously writes permanent storage notes on the spinning platters.