design and function. In combination, these features make high-speed operation attainable. Consider what one thousand operations per second means. If each instruction in a job program was used once, in consecutive order, no human programmer could generate enough instruction to keep the computer busy. Arrangements must be made for parts of the job program (called subroutines) to be used repeatedly in a manner that depends on the computation variables. Also, it would be helpful if instructions could be changed when needed during a computation to make them behave differently. Von Neumann met these two needs by developing a special type of machine instruction, called a conditional control transfer. This allowed the program sequence to be stopped and started again at any point, storing all instruction programs together with data in the same memory unit, so that, when needed, instructions could be arithmetically changed in the same way as data. As a result of these techniques, computing and programming became much faster, more flexible, and more efficient. Regularly used subroutines did not have to be reprogrammed for each new program, but could be kept in "libraries" and read into memory only when needed. Thus, much of a given program could be assembled from the subroutine library. The multi-purpose computer memory became the assembly place in which all parts of a long computation were kept, worked on piece by piece, and put together to form the final results. The computer control survived only as an "errand runner" for the overall process. As soon as the advantage of these techniques became clear, they became a standard practice. The first generation of modern programmed electronic computers to take advantage of these improvements was built in 1947. This group included computers using Random Access Memory. RAM is memory designed to give almost constant access to any particular piece of information. . T...
