MERSI protocol was used by the computer that was a fourth generation of what type of processors?
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.
Epson QX-10 The Epson QX-10 is a microcomputer running CP/M or TPM-III (CP/M-80 compatible) which was introduced in 1983. It was based on a Zilog Z80 microprocessor, running at 4 MHz, provided up to 256 KB of RAM organized in four switchable banks, and included a separate graphics processor chip (µPD7220) manufactured by NEC to provide advanced graphics capabilities. In the USA, two versions were launched; a basic CP/M configuration with 64 KB RAM and the HASCI configuration with 256 KB RAM and the special HASCI keyboard to be used with the bundled application suite, called Valdocs. The European and Japanese versions were like the CP/M configurations. TPM-III was used for Valdocs and some copy protected programs like Logo Professor.