Topic summary
RPC-4000
Extracted from the Wikipedia article LGP-30.
Design
Half of the instruction (15 bits) was unused. The unused half could have been used for extra instructions, indexing, indirect addressing, or a second (+1) address to locate the next instruction, each of which would have increased program performance. None of these features was implemented in the LGP-30, but some were realized in its 1960 successor, the RPC-4000.