Portable storage device

[1] This is slightly different from a portable media player, which is designed to only store music and video files that its internal reader softwares can play.

Most modern PSDs are dedicated solid-state drives (SSD) that are connected to a computer and powered via USB ports.

Some PSDs, usually those from before the wide adoption of SSDs, are modified hard disk drives via the installation of a disk enclosure, and require an additional AC adapter as the power required to operate the drive typically exceeds that can be provided by the USB port.

Some smaller portable hard disk drives and portable optical drives are not require additional AC adapter, but a Y-cable is recommended for provide enough USB current.

Some early models allow the user to review the images on a colour screen, but at the top end of the market.