Magnetic Drum

Data Processing Machine announcement - Press release

The following is the text of an IBM press release distributed on July 14, 1953.

International Business Machines Corp. announced today the introduction of a new commercial electronic decimal calculator designed to meet the vast accounting and computing requirements in areas between those now served by its "giant brains" and the widely-used smaller machines such as the 604 Electronic Calculating Punch and the Card-programmed Calculator.

Called the IBM Magnetic Drum Data Processing Machine, it combines one of the advanced memory devices and the stored program concept of IBM's big "701," recently announced with new high speed reading capacity in the conventional punched card equipment to achieve a powerful data processing machine for commercial and engineering requirements.

In addition to its usefulness as an accounting and computing tool, the Magnetic Drum Data Processing Machine will be a vital factor in familiarizing business and industry with the stored program principles fundamental to electronic data processing equipment. Though its capacity is large, it is designed for exceptional ease of problem preparation and operation. A significant feature of this machine is its ability to check the accuracy of its answers.

Typical application of the Magnetic Drum Data Processing Machine is the simultaneous computation of insurance premiums and calculation of required reserves.

For the automobile industry, the calculator can "remember" several weeks' or months' production schedule of finished products, and at the same time calculate at high speed the number of parts required for their production. It can take into account such factors as "lead time" and indicate the dates on which orders must be placed for each part to be available for scheduled assembly.

Because of such advanced techniques as its large stored program and its extensive memory capacity, the drum calculator can incorporate in one machine operations in punched card accounting which once required several machines. A numeric decimal machine, it has up to 20,000 memory positions and can accept as many as 2,000 individual operating instructions to facilitate commercial and scientific computations. It consists of three units. The drum and electronic calculating components are housed in two separate cabinets, one of which is provided with a console. The third unit provides input and output facilities. It occupies approximately the same area as an ordinary office desk and two filing cabinets.

All of the calculator's arithmetic operations are controlled through a program which may be entered either automatically from punched cards or manually from the operator's console and stored in the form of magnetized spots on the surface of a drum only 4" in diameter and 12" long, spinning at 12,500 revolutions a minute. The calculator's arithmetic unit operates at electronic speeds. It can: accumulate 10 digit numbers to form a 20 digit total at the rate of 200 a second; multiply 10 digit numbers by 10 digit numbers to develop a 20 digit product at the rate of 60 a second, and divide a 19 digit number by a 10 digit divisor to develop a 10 digit quotient and a 10 digit remainder at the rate of 50 a second. It has an input rate of 200 punched cards a minute and a separate output of 100 cards a minute.

In addition to its large numerical capacity, the calculator also features a "Table Look-up" operation which facilitates the automatic searching of rate tables such as occur in the utilities, life and casualty insurance, transportation and other commercial fields.

The operation of these features as they might be used in a standard commercial application of the magnetic drum calculator is illustrated by following the course of events from the time a gas and electric meter has been read to the time the bill is prepared. While the utility company representative is peering with his flashlight into those out-of-the-way places where meters often are installed, the magnetic drum calculator, back in the home office, has stored on its drum the complete rate structure of the utility and is ready to consolidate a minimum of five operations into one processing. When all the individual meter cards are fed into the machine, the drum calculator, by means of its Table Look-up feature, selects the rate applicable for each class of service, makes all the necessary calculations for the bill amount, and punches the result into another card along with the indicative information necessary for bill preparation. In this application, internally contained self-checking features virtually eliminate the necessity for separate processing of the cards for checking purposes. The entire operation materially reduces the time involved in getting out the utility company's bills.

In addition to performing all the computations necessary for billing purposes, the calculator's remaining drum capacity also can be used for the distribution of revenue or rate statistics. This cumulative information may be kept on the drum as long as desired, regardless of the disposal of the data used in the individual meter billing operation

By means of the console, the operator has control over all stages of the calculations and may manually insert instructions or data into any desired storage location, examine the contents of these locations, stop the calculation at any required point and begin calculation with any desired instruction located in the memory unit.