to perform functions which differ somewhat in their nature and considerably in their purpose, it is nevertheless tempting to treat the entire memory as one organ, and to have its parts even as interchangeable as possible for the various functions enumerated above." (Sec. 2.5) "The orders which are received by CC come from M, i.e. from the same place where the numerical material is stored." (Sec. 14.0) Von Neumann estimates the amount of memory required based on several classes of mathematical problems, including ordinary and partial differential equations, sorting and probability experiments. Of these, partial differential equations in two dimensions plus time will require the most memory, with three dimensions plus time being beyond what can be done using technology that was then available. He concludes that memory will be the largest subdivision of the system and he proposes 8,192 minor cycles (words) of 32-bits as a design goal, with 2,048 minor cycles still being useful. He estimates a few hundred minor cycles will suffice for storing the program. He proposes two kinds of fast memory, delay line and Iconoscope tube. Each minor cycle is to be addressed as a unit (word addressing, Sec. 12.8). Instructions are to be executed sequentially, with a special instruction to switch to a different point in memory (i.e. a jump instruction). Binary digits in a delay line memory pass through the line and are fed back to the beginning. Accessing data in a delay line imposes a time penalty while waiting for the desired data to come around again. After analyzing these timing issues, he proposes organizing the delay line memory into 256 delay line "organs" (DLAs) each storing 1024 bits, or 32 minor cycles, called a major cycle. A memory access first selects the DLA (8 bits) and then the minor cycle within the DLA (5 bits), for a total of 13 address bits. For the Iconoscope memory, he recognizes that each scan point on the tube face is a capacitor and that a capacitor can store one bit. Very high precision scanning will be needed and the memory will only last a short time, perhaps as little as a second, and therefore will need to be periodically recopied (refreshed). Orders (instructions) In Sec 14.1 von Neumann proposes the format for orders, which he calls a code. Order types include the basic arithmetic operations, moving minor cycles between CA and M (word load