I’d say from the discussions I’ve had with people who owned PowerStacks when they were initially being sold, 90% or so ran Motorola’s AIX when initially bought

I’d say from the discussions I’ve had with people who owned PowerStacks when they were initially being sold, 90% or so ran Motorola’s AIX when initially bought (as would be expected). The interest in NT/Solaris/etc on these machines as an install option is a more contemporary phenomenon, I think, and comes from these PowerPC ports not really getting traction and therefore being an extremely rare OS on an already rare hardware platform.