In $a(an)$ computer, each processor have its own local memory. Because all of the processors, except the controller, execute the same instructions at the same the, no synchrontzation is required in the software.

$$ MIMD $($multiple instruction, multiple data$)$

SIMD $($Single instruction, multiple data$)$

XIMD $($mixed instruction, multiple data$)$

$$ NIMD $($null instruction, multiple data$)$