olemus
ISO/IEC 27037:
digitaalsalvestuskandja (sealhulgas põhimälu) ala, mida operatsioonisüsteem pole jaotanud ning on andmete ja metaandmete talletuseks vaba
= area on digital media, including primary memory, which has not been allocated by the operating system, and which is available for the storage of data, including metadata

ülevaateid
https://threat.media/definition/what-is-unallocated-space/
https://www.quora.com/What-is-the-difference-between-free-space-and-unallocated-space