VMCS Manufacturing solution from NCR. It was an entirely que based solution that ran on VRX (mainframe environment). Blisteringly fast. Why? Intelligent use of queues, single programs that read a que, did something, put results on a que, is how bank software was done, retail software, and many more. Its a simple model that predates OOP but actually entirely consistent with OOP principles. I had privilege to see this in 80s with NCRs manufacturing and retail software, at NCR (my first job) and at there biggest user in NZ (Farmers Trading Co.).