So, the RPC-4000 version of blackjack seems lost, but the LGP-30 version exists (and can be run on simh). I've disassembled and partly annotated it, and found t

So, the RPC-4000 version of blackjack seems lost, but the LGP-30 version exists (and can be run on simh). I've disassembled and partly annotated it, and found that it too has a sort of cheat switch. The LGP-30 has no source of randomness to use as a seed. From loading the program, if the player plays optimally, the games will all be the same. Over the first few dozen games, the player ends up in the hole (IIRC, noticeably more than the long-run house edge). The LGP-30 has one conditional branch instruction, that tests the sign bit of the accumulator. But if the sign bit on the instruction is set, and the TRANSFER CONTROL switch on the front panel is set, then the branch is always taken. This appears once in the program. On startup, if the switch is set, it marks two of the aces as already dealt. This perturbs the sequence enough so that, over the first few dozen games, the player has the advantage.