@Article{rettberg:monarch, author = {Randall D. Rettberg and William R. Crowther and Philip P. Carvey and Raymond S. Tomlinson}, title = {The {Monarch Parallel Processor} Hardware Design}, journal = {IEEE Computer}, year = {1990}, month = {April}, volume = {23}, number = {4}, pages = {18--30}, publisher = {IEEE Computer Society Press}, keywords = {MIMD, parallel architecture, shared memory, parallel I/O, pario-bib}, comment = {This describes the Monarch computer from BBN. It was never built. 65K processors and memory modules. 65GB RAM. Bfly-style switch in dance-hall layout. Switch is synchronous; one switch time is a {\em frame} (one microsecond, equal to 3 processor cycles) and all processors may reference memory in one frame time. Local I-cache only. Contention reduces full bandwidth by 16 percent. Full 64-bit machine. Custom VLSI. Each memory location has 8 tag bits. One allows for a location to be locked by a processor. Thus, any FetchAndOp or full/empty model can be supported. I/O is done by adding I/O processors (up to 2K in a 65K-proc machine) in the switch. They plan 200 disks, each with an I/O processor, for 65K nodes. They would spread each block over 9 disks, including one for parity (essentially RAID).} }