Browse Prior Art Database

Data Processing System

IP.com Disclosure Number: IPCOM000097180D
Original Publication Date: 1962-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 4 page(s) / 70K

Publishing Venue

IBM

Related People

Davis, CM: AUTHOR [+3]

Abstract

The data processing system operate, in any one of several data modes. It includes checking and correction devices for performing arithmetic operations and transmitting data. An improved code encodes the data. Associated apparatus performs error detection and error correction functions. These may be expanded in order to increase the degree of detection and correction accomplished. The basic code and apparatus remain unchanged regardless of the degree or extent of expansion.

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Data Processing System

The data processing system operate, in any one of several data modes. It includes checking and correction devices for performing arithmetic operations and transmitting data. An improved code encodes the data. Associated apparatus performs error detection and error correction functions. These may be expanded in order to increase the degree of detection and correction accomplished. The basic code and apparatus remain unchanged regardless of the degree or extent of expansion.

All of the data modes utilize some or all of a basic set of sixteen messages
0...9, Z1... Z6. For coding purposes a 6, 7 or 8 binary symbol variation can be chosen as set forth in the coding table. For the 6 binary symbol variation (b(5)...b(0)), the sixteen messages have a minimum distance of two. Hence, single-error detection is available for data transmission. For the 7 binary symbol variation (b(5)...b(0) c(1)), the minimum distance is three. Hence, single-error correction is available for data transmission. For the 8 binary symbol variation (b(5)...b(0) c(1) c(2)), the minimum distance is four. Hence, single-error correction plus double-error detection are available for data transmission. The 7 and 8 binary symbol variations are optimal codes in terms of probability of correct transmission. A feature of the code is simple true-complement control for arithmetic processes.

For operation in a decimal mode (the 7N-mode) only the upper portion of the message code column, i. e., characters 0... 9, is taken into account. The term 7N is derived from the fact that the code for a decimal digit N is the binary number 7 times N represented by the binary symbols b(5)...b(0). For operation in an octal mode, the 9M-mode, a subset of eight of the sixteen basic messages referred to previously is used. That is, the octal digits M = 0, 1, 2, 3, 4, 5, 6, 7 are respectively represented by the characters 0, Z1, Z2, Z3, Z4, Z5, Z6, 9 in the coding table. The term 9M is derived from the fact that the code for an octal digit M is the binary number 9 times M represented - by the binary symbols b(5)...b(0). In the octal 9M-mode there are effectively three information digits, b5 b4 b3 or equally b(2) b(1) b(0), for each message represented in pure binary coding.

The diagram is a simplified 3-mode computer. Common circuitry processes both data words and instruction words in either pure binary coding for scientific purposes or in the checked decimal 7N-mode for commercial and business usage. Data may also be represented in the checked octal 9M-mode. All instruction words which are stored within the machine must be in the same mode. Data words may be represented by any of the three codes, i. e., pure binary, 7N- or 9M-mode. The system has various modular units and has provision for data storage and arithmetic operations besides containing certain error detection and correction circuitry. Fixed length instruction words of twenty- four information bits plus a sign bi...