Design of an All-Magnetic Computing System: Part II-Logical Design

Author(s): H. D. Crane
Publisher: IEEE - Institute of Electrical and Electronics Engineers, Inc.
Publication Date: 1 June 1961
Volume: EC-10
Page(s): 221 - 232
ISSN (Paper): 0367-9950
DOI: 10.1109/TEC.1961.5219192



A logical design technique is developed for use with the particular module developed for this system. The detailed properties of this module, as well as the philosophy that led to its particular form, were covered in Part I of the paper. Briefly, the module forms the (inclusive) OR function of two input variables. This function can subsequently be transmitted to three receivers, each transfer being independently logically positive or negative. The read-outs are nondestructive and the transmitter module must be explicitly cleared before read-in is again possible. In view of the relatively small fan-in and fan-out for this module, and since only the OR function can be directly formed during any single transfer, complex logic functions must be formed slowly, a step at a time. This step-by-step generation of functions results in the need for more modules than might otherwise be required, but aside from that, the synthesis techniques are not particularly different from those of customary logical design. In particular, the design of an arithmetic unit designed for decimal addition, subtraction and multiplication is outlined. Some comparisons are noted between this particular all-magnetic logic scheme and conventional core-diode schemes. Comparisons are also made between magnetic logic schemes in general and some other realization schemes, such as ac-operated parametrons and conventional transistor systems.