Calculators punched card

Punched cards, used to calculate interaction coefficients, 171... 

In the punched-card machines, if a calculation involved a sequence of many arithmetic operations, the machines were set up for one of these operations, which was performed on the data punched in as many cards as might be required. The machines were then... 

The earliest type of automatic digital calculator to become generally available, starting at about 1945, was the punched-card calculator. These machines were at first entirely electromechanical, but in their modern form are largely electronic. Their intended use was initially in accounting applications, but their utility in various technical problems was soon discovered. Many of the present users of large-scale calculators were introduced to computing by the punched-card calculator. 

In its simplest form the punched-card calculator is designed to perform operations based upon data values read from continuously feeding punched cards. The calculations as each card passes through the machine are usually simple and similar. It is possible to arrange for a limited number of alternative operations to take place, depending upon information punched on the card. However, the calculation performed is generally complete for each card, and the result is immediately punched into another part of the same card from which the data were read. In certain... 

The operations of a punched-card calculator are determined by the wiring of a control panel. The panel, in effect, completes circuits between components in the machine so that desired operations are carried out. The panels may be removed from the machine and saved permanently. Thus several differently wired panels may be kept on hand for different types of problems, making it a simple matter to change the functions of the machine. 

There are many problems, particularly in the field of accounting, for which the small punched-card calculator is suitable. However, for many technical or scientific calculations it is of. only limited utility, primarily because of its limited speed and a basic lack of adaptability to lengthy sequential calculations. The speed limitation comes about principally because the operation of these machines is dependent upon the mechanical movement of cards. Thus, even though electronic calculations may be performed at high speed, this feature cannot be fully exploited. 

The fact that these calculators are ill suited to long sequential calculations is due mainly to the limited facilities associated with their small size and relatively low cost. To some extent this is not an inherent limitation, but it does not pay to increase the size of a punched-card calculator indefinitely without making a radical change in the basic structure of the machine. Such a change will bring us in the next section to the stored-program type of calculator. 

The instructions which a calculator receives from punched cards are not different in form from numerical data. In fact, without knowledge of the rules of procedure for a given computer, it would be impossible to distinguish between numerical data and instructions. There is no reason, therefore, why both types of information cannot be stored within the calculator. Doing so has three important advantages ... 

Instructions can be modified by the computer. It is frequently found that the same instruction (or group of instructions) can be used repetitively if changed in some simple way. Since instructions are available in storage and can be subjected to the same arithmetic operations as any other numerical data, the computer can modify its instructions as the calculation proceeds. This permits relatively short sequences of instructions to be equivalent to much longer sequences on punched-card calculators. 

It is possible that the future may also see the use of digital calculators in qualitative spectrometric analyses. Various types of punched cards have been used as a method of recording spectral data on pure compounds. The purpose of these files is to facilitate the identification of spectral data on unknown substances. Their use in infrared analysis has been covered by Mecke and Schmid (M6), Keuntzel (K3), and Baker, Wright, and Opler (B2). The last named authors describe a file of 3150 spectra which was expected eventually to be expanded to include up to 10,000 spectra. Zemany (Zl) discussed the use of edge-notched cards in cataloging mass spectra and Matthews (M4) describes a similar application in connection with X-ray diffraction powder data. These two applications made use of only hand-sorting methods the files of Baker et al. were intended to be processed by machine. 

The data in the memory of the y-ray spectrometer was punched on 8-channel paper tape, converted to punched cards, and processed through a rather primitive computer program which provided both a count per channel output plus a not too reliable routine for peak finding and integrating net area. All results were hand calculated from net peak areas and... 

Besides the calculation of average molecular weights, several other means of characterizing the distribution were produced. These include tables of percentile fractions vs. molecular weights, standard deviation, skewness, and kurtosis. The data for the tables were obtained on punched cards as well as printed output. The punched cards were used as input to a CAL COMP plotter to obtain a curve as shown in Figure 3. This plot is normalized with respect to area. No corrections were made for axial dispersion. 

The Barrett, Joyner, and Halenda (2) method of pore size distribution calculation requires data for the volumes of vapor adsorbed at 64 relative pressures, between 0.046 and 0.967. The volume of gas in the system at these pressures may be read from a smooth curve drawn through the equilibration points of the chart record or may be interpolated mathematically from a set of data points. In the procedure used, the pressure-volume points, and other data pertinent to the sample and the experiment, are listed in a form convenient to transcribe by key punch to IBM cards. The arrangement of the data on the punch cards is determined by the particular computer program. In this case, a program of the Barrett, Joyner, and Halenda method of pore size distribution calculation had been written for an IBM 704 data-processing unit. 

The first industrial jobs for computational chemists opened in the early 1960s when such scientists were usually called theoretical chemists or physical chemists. Those early pioneers not only had to prove themselves, they had to prove a whole new approach to answering questions in science, that is, computationally. Human nature being what it is, traditional (experimental) chemists reacted in different ways to computational chemistry some were curious (some of whom even tried their own hand at calculations but often found the early technology—computer punch cards—too bothersome), some were disinterested, and some felt their prerogatives and perquisites were threatened. At the pharmaceutical companies, many of the medicinal chemists (who far outnumbered the computational chemists) were skeptical, if not resentful, of the upstarts." Because of finite resources, one more person hired as a physical (or analytical) chemist often mean one less organic chemist would be hired. 

The calculation of temperatures and equilibrium compositions of gas mixtures involves simultaneous solution of linear (material balance) and nonlinear (equilibrium) algebraic equations. Therefore, it is necessary to resort to various approximate procedures classified by Carter and Altman (Cl) as (1) trial and error methods (2) iterative methods (3) graphical methods and use of published tables and (4) punched-card or machine methods. Numerical solutions involve a four-step sequence described by Penner (P4). 

Ajit Thakkar, bom in Poona, India in 1950, left home at 17 to explore the West. A circuitous route led him to Queen s University in Kingston, Ontario. A summer job programming calculations of virial coefficients and transport cross-sections using FORTRAN IV, dreadful JCL, and punched cards on an IBM 360/50 drew him to computational chemistry. In 1976, he completed a Ph.D. in theoretical chemistry guided by Vedene Smith and influenced by Robert Parr. His faculty career began at the University of Waterloo and, since 1984, continued at the idyllic Fredericton campus of the University of New Bmnswick. He is now a University Research Professor, and author of more than 200 articles on molecular properties, electron densities and intermolecular forces. 

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