Data Backup Glossary (Letter P)

Physical erase unit
A physical erase unit is the smallest memory area of the flash memory media that can be erased in a single erase operation. Its size varies between flash devices.

A physical entity that contains nodes. Platforms include all end devices that are attached to a Fabric, for example, hosts and storage subsystems. Platforms communicate with other platforms in the storage area network using the facilities of a Fabric or other topology

Portable image storage device
A small, portable storage device used for storing and viewing your digital images. The device is a portable hard drive in an enclosure that resembles handheld game consoles. The device usually offers USB and memory card readers as options for transferring your images directly to the device, as well as an LCD display for viewing the stored images. The device  may also have different controls for maneuvering through the images, such as forward, random, skip, and so on.

Primary storage
A somewhat dated term for main memory. Mass storage devices, such as disk drives and tapes, are sometimes called secondary storage.

A set of rules that control an interaction between two or more entities in communication with one another, for example,  TCP ports, Fibre Channel FC-4 processes, and polite humans.