Question: MERSI protocol was used by the computer that was a fourth generation of what type of processors?

Context paragraphs:
Toyota Kijang: The Toyota Kijang (Japanese: トヨタ・キジャン , Toyota Kijang ) , an acronym of "Kerjasama Indonesia-Jepang" (English: Indonesian-Japan Cooperation), is a series of pickup trucks and MPVs sold mainly in Southeast Asia by Toyota.  "Kijang", meaning deer/muntjac in Indonesian, was first introduced in Indonesia in 1977 and it has become the most popular car in the country.  The same vehicle was earlier produced in the Philippines as the Toyota Tamaraw, where it was launched in December 1976.  Fourth generation models in the Philippines were sold under the Toyota Revo name.  This car also sold in other countries, and is known as the Toyota Qualis in India and Nepal (third and fourth generation), Toyota Zace in Taiwan (third and fourth generation), Toyota Unser in Malaysia (fourth generation), and Toyota Stallion in Africa for the basic models (second, third and fourth generation), with higher specifications labelled Toyota Venture (third) and Toyota Condor in South Africa (fourth generation).

Fourth generation of video game consoles: In the history of computer and video games, the fourth generation (more commonly referred to as the 16-bit era) of games consoles began on October 30, 1987 with the Japanese release of NEC Home Electronics' PC Engine (known as the TurboGrafx-16 in North America).  This generation saw strong console wars.  Although NEC released the first fourth generation console, and was second to the Super Famicom in Japan, this era's sales were mostly dominated by the rivalry between Nintendo and Sega's consoles in North America: the Super Nintendo Entertainment System (the Super Famicom in Japan) and the Sega Genesis (named the Mega Drive in other regions).  Nintendo was able to capitalize on its previous success in the third generation and managed to win the largest worldwide market share in the fourth generation as well.  Sega was extremely successful in this generation and began a new franchise, Sonic the Hedgehog, to compete with Nintendo's Mario series of games.  Several other companies released consoles in this generation, but none of them were widely successful.  Nevertheless, several other companies started to take notice of the maturing video game industry and began making plans to release consoles of their own in the future.  This generation ended with the discontinuation of the Neo Geo in 2004.

Two-phase commit protocol: In transaction processing, databases, and computer networking, the two-phase commit protocol (2PC) is a type of atomic commitment protocol (ACP).  It is a distributed algorithm that coordinates all the processes that participate in a distributed atomic transaction on whether to "commit" or "abort" ("roll back") the transaction (it is a specialized type of consensus protocol).  The protocol achieves its goal even in many cases of temporary system failure (involving either process, network node, communication, etc. failures), and is thus widely used.

Samuel Curtis Johnson Jr.: Samuel Curtis Johnson Jr. (March 2, 1928 – May 22, 2004) was an American businessman.  He was the fourth generation of his family to lead S. C. Johnson & Son, Inc., which is headquartered in Racine, Wisconsin.  He was the son of Herbert Fisk Johnson Jr. and the great-grandson of company founder, Samuel Curtis Johnson Sr. Johnson, a celebrated business icon, turned a relatively small wax company into a multibillion-dollar global household name.  A noted philanthropist and environmentalist, Johnson led his company and community "to protect this planet and leave it a better place for future generations to live," noting, "A good executive, a busy executive, always has time to do some other things, especially for the good of the community."

Stimulus protocol: In telephony, a stimulus protocol is a type of protocol that is used to carry event notifications between end points.  Such a protocol is used to control the operation of devices at each end of the link.  However a stimulus protocol is not sensitive to the system state.  In a typical application such a protocol will carry keystroke information from a telephone set to a central call control.  It may also carry control information for simple types of text displays.  MiNET from Mitel is a typical protocol of this sort.

Functional protocol: In telephony, a functional protocol is a type of protocol that is used to carry signaling messages between end points.  Such a protocol is used to control the operation of devices at each end of the link.  The adjective functional is used to describe protocols that are aware of the system state of the endpoints.  Session Initiation Protocol (SIP) is a currently popular protocol for Voice over IP (VoIP) and other applications.

Dragon write-back update protocol: The Dragon Protocol is an update based cache coherence protocol used in multi-processor systems.  Write propagation is performed by directly updating all the cached values across multiple processors.  Update based protocols such as the Dragon protocol perform efficiently when a write to a cache block is followed by several reads made by other processors, since the updated cache block is readily available across caches associated with all the processors.

PowerPC G4: PowerPC G4 is a designation used by Apple Computer and Eyetech to describe a "fourth generation" of 32-bit PowerPC microprocessors. Apple has applied this name to various (though closely related) processor models from Freescale, a former part of Motorola.  Motorola and Freescale's proper name of this family of processors is PowerPC 74xx.

Stanford DASH: Stanford DASH was a cache coherent multiprocessor developed in the late 1980s by a group led by Anoop Gupta, John L. Hennessy, Mark Horowitz, and Monica S. Lam at Stanford University.  It was based on adding a pair of directory boards designed at Stanford to up to 16 SGI IRIS 4D Power Series machines and then cabling the systems in a mesh topology using a Stanford-modified version of the Torus Routing Chip.  The boards designed at Stanford implemented a directory-based cache coherence protocol allowing Stanford DASH to support distributed shared memory for up to 64 processors.  Stanford DASH was also notable for both supporting and helping to formalize weak memory consistency models, including release consistency.  Because Stanford DASH was the first operational machine to include scalable cache coherence, it influenced subsequent computer science research as well as the commercially available SGI Origin 2000.  Stanford DASH is included in the 25th anniversary retrospective of selected papers from the International Symposium on Computer Architecture and several computer science books, has been simulated by the University of Edinburgh, and is used as a case study in contemporary computer science classes.

MERSI protocol: The MERSI protocol is a cache coherency and memory coherence protocol used by the PowerPC G4.  The protocol consists of five states, Modified (M), Exclusive (E), Read Only or Recent (R), Shared (S) and Invalid (I).  The M, E, S and I states are the same as in the MESI protocol.  The R state is similar to the E state in that it is constrained to be the only clean, valid, copy of that data in the computer system.  Unlike the E state, the processor is required to initially request ownership of the cache line in the R state before the processor may modify the cache line and transition to the M state.  In both the MESI and MERSI protocols, the transition from the E to M is silent.

Supporting paragraphs: MERSI protocol PowerPC G4
Answer: 32-bit PowerPC