IBM System/7 Functional Characteristics - All about the IBM 1130 ...

DATA FORMATSInput/output data can be represented in a variety of ways, depending upon the mediumused. (A medium is the material on which data is recorded.) For example, a paper tapethat is punched with holes (which represent data) is a medium; the paper tapes can beread by a paper tape reader.To be accessible to the program during processing, data must be in storage or aregister. Thus, input data is read by an input device, placed in storage or a register, andthen processed. Results (output data) are sent to an output device.Since System/7 storage is organized in units of 16-bit words, data is read from orplaced in storage on a word basis. The bits in a word are numbered left to right, from0 to 15 as shown below.0 15I I I I I I l I i l I IThe above format is used throughout this manual to represent a word of System/7storage. The three major division marks inside the block are separations between hexadecimalcharacters in the word. The smaller divisions separate bit positions within the word.The leftmost bit (0) is the high-order bit; the rightmost bit (15) is the low-orderbit. Each bit can be set to either a binary 1 (on value) or a binary 0 (off value).Bits in a word can contain all ones, all zeros, or any combination of both zeros andones, such as:All zerosBit—D-01 2 3 4 5 6 7 8 9 10 11 12 13 14 15Value—o- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0All onesBit—►0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Value—o-1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1Any combinationBit —D-01 2 3 4 5 6 7 8 9 10 11 12 13 14 15Value-0-1 0 0 0 1 1 0 1 0 1 1 1 0 0 0 1O ►0 1 1 1 0 0 1 1 1 1 1 0 0 0 0 0Or 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1IBM 5010 Processor Module 2-7