Patent GB-752593-A (GB)
Title: Improvements in or relating to statistical record controlled sorting apparatus
IPC: G11B27/036
Filed: 1954-05-21
Abstract: 752,593. Statistical apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 21,1954 [May 26, 1953], No. 15051/54. Class 106 (1). Apparatus for sorting information carried on a tape in sequential arrangement in the form of characters or numerals each comprising sequentially arranged " bits " comprises means for feeding the tape past a reading station adapted to generate a signal representative of each " bit ", and means selectively operable by such signals upon a first pass of the tape to write upon a second tape all characters having a selected characteristic, and upon a second pass of the tape in the same direction to write characters not having the said characteristic on the second tape. Only two tapes are employed for the sorting operation using a modified binary code written serially in two tracks one along each edge of the tape, the " Yes " bits on one track and the " No " bits on the other. The information tape must be passed and rewound twice per bit sort. If the data is to be arranged in ascending order the first pass transfers all records containing a " No " bit and the second pass transfers all records in which a " Yes " has been recognized. The opposite order of transfer under bit control is employed if a descending order is required. Eight passes of the tape are necessary for a complete numerical sort and twelve passes for a complete alphabet sort. Referring to Fig. 1, a pair of tape units 1 and 2 are provided for driving the tapes through the writing, reading and erasing heads during the several passes which constitute a complete sorting operation. The signals received from the tape units by the tape unit transfer controls are by nature distorted. The pulse generator receives these distorted signals and transforms them into uniform shape. The pulse generator limits two kinds of impulses, one being the pulse originating at head " A " and the second being that originating at head " B " the first being the " read " pulse and the second the " write " pulse. An ERM recognizer is provided which functions to recognize the fact that a complete record has been written on the output tape. Signals from the pulse generator having their origin at the " A " or reading head are transmitted to the shift register and matrix which consists of a set of storage elements that store the characters read from the tape in order to recognize certain control characters required for machine operation. The Record Transfer control decides whether a record read from the input tape is transmitted to the output tape or not during any one pass of the input tape. The circuit receives the " Yes " and " No " pulses from the pulse generator which in conjunction with various control pulses cause a character to be transcribed to the receiving tape at any given time. The Bit Counter consists of an electronic ring counter of seven stages that runs in synchronism with signals transmitted from the " A " head of the pulse generator. As the bit counter rotates it actuates control elements within the various bit selection switches which consist of a series of electronic switches shown directly above the bit counter in Fig. 29c. The position of the bit selection switches determines which bit within a character is to be processed. The character counter also shown in Fig. 29c consists of two binary decimal counters which are set up under control of the units and tens step switches. The character counter is impulsed by a carry pulse emitted from the bit counter. Thus as one character is completely read from the tape the bit counter will have completed an entire revolution, at which time it will transmit a carry pulse to the character counter. When the character counter in turn limits a carry pulse, a signal is transmitted to the record transfer control and is there utilized in conjunction with the bit selection switches to determine whether or not the particular record under examination is to be transferred. A plugboard is provided to programme the sorting operation in which there are ten consecutive programme levels. A sorting bit step switch determines whether the sorting circuits are to scan the tape generated pulses for " Yes " or " No " bits during any given pass of the tape. The sorting bit step switch advances one position upon the sorting of each bit and when the switch has advanced through the number of positions by which a character is represented a complete character sort is recognized and a signal is transmitted to the columnsper-sort switch. This latter switch causes recognition of the fact that columns have been sorted and that consequent fewer columns remain to be sorted, i.e. the columns per sort switch in fact counts the columns as they. are sorted. As the sorting bit step switch is rotated it produces a signal upon the completion of each complete column sort, and this signal is transmitted to the columns per sort step switch whereby the columns per sort step switch is actuated to reduce the count of the columns to be sorted. On completion of the sorting of the number of columns for which the sorter was conditioned by the plugboard the columns per sort switch emits a signal to the control field selector step switch, which is in effect the programming device of the sorter since on receipt of a signal from the columns per sort switch the control field selector switch advances to the second programme level. If the second programme level is wired to the stop hubs the sorting operation is then completed. Fig. 3 shows a tape T1 which has arranged thereon in random fashion the numbers 60, 43, 49, 78, 22, 66, 41 and 84; and it is desired to arrange these numbers in ascending order the sorting circuits will first examine each of the unit digits to determine the presence of a " Yes " or " No " bit in the 1 weight representation thereof on tape T1. During the first pass of the tape T1 the unit values of each group of numbers are sorted for the 1 weight bit and those which contain a " No " in the 1 weight are transferred to tape T2 in the order in which they are encountered, thus the " No " bits. in the 1 weight of unit digits ' 5 ', ' 3 ', ' 9 ' and ' 1 ' will result in the transfer of the numbers 35, 43, 49 and 41. Tape T2 is now stopped and tape T1 is rewound. Both tapes are again run and all of the number groups of T1 whose unit digits are represented by a " Yes " in the 1 weight thereof are transferred. This results in the transfer of the numbers 60, 78, 22, 66 and 84 as shown in tape T2, Fig. 3a. Both tapes are now rewound and tape T1 is either replaced by a blank tape or erased for use as an output tape. Tape T2, Fig. 3a, now becomes the file tape and tape T1 becomes the record or output tape. The second sort of the unit digits of the numbers on T2 in Fig. 4 now proceeds to an examination for a " No " bit in the 2-weight and all units having a " No therein are transferred to T2. This results in the transfer of the numbers 35, 49, 41, 22 and 66 as shown in T1 of Fig. 4. Tape T1 is now stopped and tape T2 is rewound. Both tapes are now run again to transfer all the numbers having a " Yes " bit in the units 2- weight thereof and then results in the transfer to tape T1 of the numbers 43, 60, 78 and 84 as shown on tape T1 of Fig. 4a. Tapes T1 and T2 are now rewound. During the 4-weight sort tape T1 is again the file or input tape and T2 is the receiving or output tape. During the first pass on the 4-weight sort the unit digits of the numbers on tape T1 are examined for the presence of a " No " in the 4-weight thereof which results in numbers 35, 66, 60 and 78 being transferred as shown on tape T2 of Fig. 5. At this point tape T2 is stopped and tape T1 is rewound. During the second pass of the 4-weight sort all the numbers having a " Yes " bit in the units column will be transferred to tape T2, this results in numbers 49, 41, 22, 43 and 84 as shown in tape T2 of Fig. 5a. At this point the tapes are rewound, tape T2 becomes the input tape and tape T1 becomes the receiving tape. During the first pass of the 8-weight sort the units columns of tape T2 will be sensed for the presence of a " No " in the 8-weight column thus numbers 60, 41, 22, 43 and 84 are transferred, Fig. 6. Tape T1 is stopped and tape T2 rewound. Both tapes are started and all numbers on tape T1, i.e. those having a " Yes " in the 8-weight are transferred to tape T1, thus numbers 35, 66, 78 and 49 will be transferred and tape T2 will have the data arranged thereon with the units in ascending order as shown in Fig. 6a, i.e. the numbers on tape T1 at the end of the 8-weight sort will be arranged as follows: 60, 41, 22, 43, 84, 35, 66, 78, 79, i.e. the units digits are arranged in ascending order. In order to complete the sort it is merely necessary to repeat the process for the tens digits in the same fashion as shown in Figs. 7-10a inclusive. Referring to the circuit, Fig. 29, a relay T1-T2 reverses the reader and writer relationship of the tapes, when this relay is down, i.e. normal position T1 is the reader and T2 is the writer. A pulse from the reader head goes to the inverter 10, which removes noise generated on the lines and inverts the pulse from its associated amplifier. The outputs of the inverters 34, 36, Fig. 29a, are fed into peakers 42 and 44. These convert the pulses into short high-speed pulses. The output of the peakers 42 and 44 is in turn fed into switch units 46 and 48 via pass rewind relay 50 which cuts off switches 46, 48, during a rewind operation thus preventing further processing of any pulses generated. A trigger 52, Fig. 29b, is provided as a short-term memory device adapted to retain the character of the last bit read from the tape. The pulses sent from inverters 38, Fig. 29a, 40 are transmitted to a single short multivibrator 57 and to an inverter 58. The single short multivibrator will produce a short time delay allowing the " Yes " or " No " pulse to go through and operate the t