mSATA and eSATA are two different types of interfaces used for connecting storage devices to a computer, and they have different purposes and characteristics.
mSATA (mini-SATA) - is a small form factor SSD (solid-state drive) interface that uses the same signaling protocol as the standard SATA interface, but in a smaller physical size. mSATA drives are typically used in portable or compact devices, such as laptops or tablets, where space is limited. They are designed to be installed internally in the device's motherboard and are used for primary storage, just like standard 2.5-inch SATA SSDs.
eSATA (external SATA) - is an interface used to connect external storage devices, such as hard drives or SSDs, to a computer. eSATA uses the same signaling protocol as SATA, but with a different physical connector and cable that allows for longer cable lengths and better shielding against electromagnetic interference. eSATA is typically used for high-speed data transfer, such as backing up large files or streaming HD video, and is commonly found on desktop computers, servers, and external hard drive enclosures.
In summary, mSATA is used for internal storage in portable devices, while eSATA is used for external storage connections in desktop computers and servers.