Now a day’s amount of data growing day by day accordingly the size of storage media is also increasing rapidly. In most of the storage devices flash memories are used one of them is Solid State drive. Solid state drives i.e. SSDs are non-volatile data storage devices which store persistent data in NAND or NOR i.e. in flash memories, which provides similar functionality like traditional hard disk (HDD). In this paper we studied internal architecture and functionality of SSDs as well as comparative study of host interfaces like Serial ATA (SATA), Serial Attached SCSI (SAS), PCI Express (PCIe), Non-volatile Memory Express (NVMe) etc