 A "disk-on-a-module" ("DOM") is a flash drive with either 40/44-pin Parallel ATA (PATA) or SATA interface, intended to be plugged directly into the motherboard and used as a computer hard disk drive (HDD).DOM devices emulate a traditional hard disk drive, resulting in no need for special drivers or other specific operating system support.DOMs are usually used in embedded systems, which are often deployed in harsh environments where mechanical HDDs would simply fail, or in thin clients because of small size, low power consumption and silent operation.