Do you know what is Net Yaroze?

Net Yaroze is a version of the PlayStation called the Net Yaroze was also produced. It was more expensive than the original PlayStation, colored black instead of the usual gray, and most importantly, came with tools and instructions that allowed a user to be able to program PlayStation games and applications without the need for a full developer suite, which cost many times the amount of a PlayStation and was only available to approved video game developers. Naturally, the Net Yaroze lacked many of the features the full developer suite provided. Programmers were also limited by the 2 MB of total game space that Net Yaroze allowed. That means the entire game had to be crammed into the 2 MB of system RAM. The user couldn't officially make actual game discs. The amount of space may seem small, but games like Ridge Racer ran entirely from the system RAM (except for the streamed music tracks). It was unique in that it was the only officially retailed Sony PlayStation with no regional lockout; it would play games from any territory.

credits: wikipedia.org