Sperry Rand Corporation

Jerry Hudson Pertl

Howard A Koehler

Glen Roy Kregness

This invention relates to an apparatus and method for preventing a digital computer from erroneously outputting data contained in an output word to another digital computer or peripheral device. A portion of the output word is allocated as a key field which must be matched with a predetermined lock value before the digital computer will allow an output of the data field of the output word to occur. That is, a key value specified as part of the output word must match a predetermined lock value before an output transfer of the data field of the output word is allowed to take place. If the lock value and key value do not match, the central processor section of the digital computer is interrupted. This apparatus and method not only verifies the correct operation of the digital computer output data transfer hardware by preventing an erroneous transfer of the data field of the output word but also alerts the central processor section in the event of a mismatch by means of an interrupt.

Method and apparatus for preventing erroneous data transfer from a

This invention relates to a right justified mask transfer apparatus which may be effectively utilized in a digital data computer. A right justified mask transfer register is provided which holds the result of a logical bit-by-bit ANDing of a multi-bit data word with a multi-bit mask work such that only those bit positions for which the mask word are of a predetermined binary significance are collected contiguously in the mask transfer register, all other bit positions being ignored. Further operations on intermediate digital data computations may be more easily performed by utilizing the right justified mask transfer function to select certain data bits or fields.

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Bloomington, MN, United States of America

Jerry Hudson Pertl