It was designed to be more sophisticated than a mere droid brain. It included hardware for interacting with its owner, and primarily acted as a personal assistant.
The Personal Droid was programmed to act as a personal assistant for its owner. It would keep track of important information and take care of tedious duties. It was more useful than a simple organizational computer in the fact that it could react to unexpected developments. It was also used as an entertainment device, since it could carry on simple conversations on a variety of topics and was programmed to play many popular games such as Sabacc and Pazaak.
The people of Samaria were so enamored with their PDs, that they never went anywhere without them and began to refer to them by the affectionate nickname of "Peteys". An offworlder would be presented with their own "Petey" when they were said to have been "adopted" as an honorary Samarian, as was Bog Divinian before he was elected as the planet's ruler. His first official act was to discard his "Petey" and encouraged his fellow Samarians to do the same. They lined up by the hundreds to comply with the wishes of their new, and much beloved, leader, putting an end to the PDs service life.
The Personal Droid was often referred to as "PD" or "Petey". It would store every fact about its user; including financial data, food preferences, and even the amount of fuel in the owner's vehicle. It was a lightweight unit that was often worn on the shoulder or in a specialized holster.
- Scavenger's Guide to Droids