Can the two CPUs in a commodore 128 run at the same time?

The Commodore 128 has two CPUs. One is some variant of the 6502, and the other is a Z80. One CPU is there for compatibility with the Commodore 64, and the other is there presumably to give basic compatibility with the CP/M titles that were available at that time. My question is whether those two CPUs can run at the same time, both accessing memory and the graphics and sound subsystems, or if one has to be disabled or halted while the other runs....Read more