The JOHNNIAC was an early computer built by the RAND Corporation (not Remington Rand, maker of the contemporaneous UNIVAC I computer) and based on the von Neumann architecture that had been pioneered on the IAS machine.[1] After being rescued from the scrap heap twice, the machine is currently at the Computer History Museum in Mountain View, California.There was only one test condition, whether or not the high bit of the A register was set.In March 1955, 4096 words of magnetic-core memory were added to the system, replacing the earlier Selectrons.Numerous changes were made to the input/output peripherals as well, and in 1964, a real-time clock was added to support time-sharing.