Development on the PlayStation 4 has been tracked back to almost two years ago. The LinkedIn page of a former Sony research and development director (via Videogamer) indicates the firm has been at work on its next-generation PlayStation since at least August 2010. Sony has been building the PS4 for a while now, it seems.

　　This staffer says he contributed to the graphics library and security features of the mysterious "Next Generation PlayStation" during his time at Sony. Previously, the developer worked on a range of Sony hardware, including the PlayStation 2, PSP, PlayStation 3, and PlayStation Vita.

　　As of press time, Sony had not responded to GameSpot's request for comment.

　　Sony's 2012 Electronic Entertainment Expo media briefing last month came and went without any news of new hardware from the company. Regarding when gamers might see the PS4, PlayStation CEO Andrew House said the company won't show the new hardware until it can demonstrate a "significant" leap over the PS3.

　　A recent analyst report predicts Sony--and Microsoft--will have their respective future-generation consoles on store shelves by the end of next year. Sony's PS4 is rumored to boast the same graphics card as Microsoft's next Xbox, as well as measures to block out used games, though analysts do not find this claim likely.

　　Overnight, Sony purchased cloud gaming company Gaikai for $380 million. The publisher intends to use the acquisition to establish a new cloud service combining Gaikai's resources with its own.

　　For more on the PS4, check out GameSpot's rumor roundup feature.