Amdahl, National Advanced Systems, Nixdorf et al have delivered performance data for their IBMulators to Big Mother, and, teeth gritted, IBM has told them into which Group each of their machines falls for the purposes of the new one-time licences for system software that was introduced with the 9370s – and if anyone think’s that’s easy, try memorising this: Group 40 is 3090s (that is easy, but why not Group 4?); Group 30 is all 4381s above the 4381-11; Group 20 covers the 9377/90 and 9375/60; and Group 10 is the 9375/40 and the 9372/20.