what is a solid state external hard drive
Solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies as memory to store data persistently. It is also sometimes called solid-state disk;[1] the word "disk" is inappropriate since SSDs do not have physical disks. SSDs primarily use traditional hard disk drive (HDD) interfaces, such as SATA and SAS, greatly simplfying usage of SSDs in computers.[2] Following the initial acceptance of SSDs with HDD interfaces, new I/O interfaces like M.2 and U.2 have been designed to address specific requirements of the Flash memory technology used in SSDs.
USB flash drive USB flash drives use the USB mass storage device class standard, supported natively by modern operating systems such as Windows, Linux, macOS and other Unix-like systems, as well as many BIOS boot ROMs. USB drives with USB 2.0 support can store more data and transfer faster than much larger optical disc drives like CD-RW or DVD-RW drives and can be read by many other systems such as the Xbox 360, PlayStation 3, DVD players, automobile entertainment systems, and in a number of handheld devices such as smartphones and tablet computers, though the electronically similar SD card is better suited for those devices.