Accounting machines, IBM 1403, and why 132 columns are the standard for printers
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Have you ever wondered why text widths of 132 characters are so popular with printers? Many printers produced lines of 132 characters each, for example, a breakthrough Centronics 101 dot-matrix printer (1970), ubiquitous DECwriter II terminal (1975), Epson MX-80 dot-matrix printer (1981), and Apple Daisy Wheel Printer (1983). Even on CRT terminals, for example, on DEC VT100 (1978) there was support for 132 speakers. But where did the 132 columns come from?

Having studied the question, I came to the conclusion that there are two answers. The first is that in 132 columns there is nothing special. Early printers were surprisingly diverse in the question of line lengths - among them were lines of 50, 55, 60, 70, 73, 80, 88, 89, 92, 100, 118, 120, 128, 130, 136, 140, 144, 150 lengths and 160 characters. This suggests that there are no convincing technical or commercial reasons for using exactly 132 columns. Instead, 132 columns became the de facto standard because of the popularity of the IBM 1401 computer and its 1403 high-speed linear printer, which printed 132 columns each.

The second, more interesting answer is that various factors in the data processing history, some of which have turned a hundred years old, led to the standardization of several sizes of printed text. One of them became the standard for paper for a linear printer, which fit 132 characters.

IBM 1401 computer and 1403 printer

The first printer to use the 132 columns seemed to be the IBM 1403, which served as an output device for the IBM 1401 business computer. The IBM 1401 was the most popular computer in the early 1960s, mainly due to its low cost. Early computers were found only in large corporations, because they were expensive; IBM 705 computer rental cost $ 43,000 per month (at current prices it is almost $ 400,000). But IBM 1401 could be rented for $ 2500 per month, which opened access to this market for medium-sized businesses that used it to calculate payroll, inventory, bookkeeping and other business tasks. As a result, by the mid-1960s, companies used more than 10,000 IBM 1401 computers.

IBM 1403 printer in front of the popular 1401 business computer (729) and 729 tape drives (left)

The IBM 1403 printer was an important part of the success of the 1401st. This high-speed linear printer could print up to 600 lines of quality text per minute, and was considered the best quality printer before the appearance of the laser. “Even today, the 1403 printer remains the standard for high-speed shock printing quality,” at least from an IBM point of view. By the end of the 1960s, half of the endless forms were printed on IBM 1403 printers.

Due to the high popularity of the printer, its 132 column format became the de facto standard, and later printers and terminals began to support it for backward compatibility. Paper size 14 7/8 "× 11" with green stripes is still popular today, and is sold in stationery stores.

Accounting machines / tabulators

Now let's discuss the story that led to the appearance of 132 columns on paper 14 7/8 ". The main actor in it is the accounting machine, or tabulator . Now these machines are almost forgotten, but in the precomputer era they were the basis of data processing in business. The history of tabs goes back to the US census of 1890, when Herman Hollerith invented a machine for tabulating the data (that is, their counting) stored on punch cards. Later, the tabulators used relays and electromechanical counters to sum the values, “programmed and »to perform various tasks with the help of switching panels with wires, and it could process up to 150 punched cards per minute.

IBM 403 electrical accounting machine. On the left you can see a patch panel with yellow wires. The printer carriage is visible from above. Cards are fed to the boot tray on the left.

It can be confusing that the word "tabulator" meant two different machines. Historically, the "tabulator" called the person who makes the table. The first type of machine called the “tabulator” was the Hollerith machine, working with punch cards, processing punch cards for the 1890 census. Note that these tabs displayed the output on the dials, and did not print anything, including any tables.

A copy of the Hollerith tabulator. The cards were inserted manually on the right, and the dials showed the results.

The second type of tabulator was a tabular typewriter (1890). It was just typewriters with stops that made it easy to type information in the form of tables (the tab button on a modern keyboard comes from these machines). The decimal tabulator (1896) had several tab keys that allowed indents for numbers consisting of one, two, three, etc. marks.

Typewriter Underwood 6 with a decimal tabulator (1934)

Later IBM tabulators, working with punch cards, got a printer and the ability to display indented data, thus becoming tabulators in both senses. Soon after, IBM ceased to call them tabulators and began to call electronic accounting machines (Electric Accounting Machine, EAM; 1934).

By 1943, tabulators were popular with commercial enterprises and governments; IBM served about 10,000 tabs. These machines were complex, they could process conditions by adding or subtracting data with three levels of intermediate values, and formatting alphanumeric output. Accounting machines have been used for a variety of data processing tasks - accounting, inventory, billing, issuing checks, printing postal labels or even W-2 tax forms. And although they were developed for commercial use, in the 1930s and 40s they were also used for scientific purposes, the most famous of which was the simulation of a nuclear bomb in the Manhattan project .

Accounting machine IBM 285 (1933)

The earliest tabulators displayed the results on mechanical counters, and the operator had to record them after each subtotal. The development of the printing device for the tabulator in the 1920s eliminated this inconvenient manual stage. One of the popular printing tabs was the IBM 285, introduced in 1933. This machine printed values ​​using from 3 to 7 “printing sets”, each of which consisted of 10 bars with numbers. The picture below shows the output in 7 columns, created by the 285th tabulator with seven printed sets.

Conclusion IBM 285 Electric Accounting Machine, with 7 columns. The standard for typewriters is the line spacing (6 lines per inch), with double the distance between the lines. Headings were printed on forms in advance.

The distance between the characters was 5/32 "(the importance of this value will appear later), which gave columns of 1 7/8" wide. This distance was 50% more than the standard typewriter (10 characters per inch), although the tabs used the standard line spacing (6 lines per inch). As seen in the picture, this resulted in large spaces between the characters. So why did the accounting machine use the 5/32 "character spacing? To understand this, you need to go back a decade ago.

IBM's early punched cards had 45 columns with round holes 5/32 "apart. The picture below shows one of these cards. Each column had one hole denoting a number from 0 to 9. One of the machines used to work with punch cards, was an “interpreter.” She read the card and printed its contents on its upper part, above the holes. The interpreter used a printing mechanism for 45 columns, and the printing bars were located 5/32 "from each other, so to match otv TIFA.

IBM 45-column punch card from the early 1920s. The card used round holes, as opposed to rectangular ones, on more “modern” 80-column punched cards.

In 1928, IBM introduced the "modern" punch card, which contained 80 columns of data (see below). The cards used rectangular holes so that they could be positioned closer to each other (at a distance of 0.087 "from each other). However, IBM retained many of the mechanisms developed for 45-column maps with their 5/32 distance. As a result, such mismatched products appeared as an interpreter of the IBM 550 (1930), which read an 80-column perforated card and printed 45 characters in it at the top. As a result, the characters were not aligned along the holes, as can be seen below. For the same reason, the 285th accounting machine used a printer with printing rods with a distance of 5/32 ", although it worked with 80-column punched cards.

Интерпретатор карт IBM 550 считывал данные с 80-колоночной перфокарты и распечатывал 45 символов этих данных наверху

Бухгалтерские машины IBM 405 (1934) и 402 (1948)

The IBM 285 tabulator could print only numbers, but in 1934, IBM introduced the 405th tabulator, which could print alphanumeric information, followed by an improved 402nd accounting machine in 1948. The alphanumeric output greatly expanded the use of the tabulator, since it could now print invoices, labels with addresses, employee records, or other forms that required alphanumeric data. The IBM 405 had 88 print rods moving vertically to print an output line (see below). Pay attention to the gap between the blocks of rods, where the rubber guide is placed.

The IBM 405 printed with two sets of printing rods: 43 alphanumeric left and 45 digital right.

The figure below shows an example of the issuance of the 405th tabulator, where alphanumeric characters are visible on the left. Like the earlier tabs, the distance between the characters in 5/32 "leads to widely spaced characters. The tabs and frames of the tabulator did not print, they were printed on the form in advance. The

output of the IBM 405 tabulator, in the form of an account. Apparently, then cocaine was a common product.

At first, the forms were hand-made sheets of paper, but then, for convenience, they were changed to permanent feed forms. So that the forms do not slide off, they began to make perforations along the edges of the paper, so that the forms could be submitted using pin mechanisms. Often, these forms used a 1/2 "wide strip at the edges, which could be removed along with perforations. Therefore, the distance from the hole from one edge to the hole from the other was 1/2" already the total width, and the area where it was possible to print, was at 1 "already a total width.

Enterprises ordered forms specially made for their needs, but usually they made standard widths. And, surprisingly, these seemingly arbitrarily chosen dimensions still remain standard today. Many of the standard shapes have a width, rounded to full inches, like 8 "and 11", however, there are also strange values, for example, 27/32 "or 18 15/16".

Dimensions, multiples of 1 7/8 ", originated from the IBM 286 tab, which could have from 3 to 7 printing sets with a width of 1 7/8". As a result, such standards were born width forms as 8 ", 9 7/8", 11 3/4 ", 13 5/8" and 15 1/2 "(including small fields). Many of the standards are then rounded to the whole inches, for example, 11 "and 16".

Width 12/27/32 "originated from ring binders with an arched mechanism for free fastening of papers, which appeared in 1896. In 1916, manufacturers of such folders gathered for a conference in Atlantic City, where they agreed on standard sizes: 9 1/4" × 11 7/8 ", 11 1/4" × 11 7/8 "and 7 1/2" × 10 3/8 ". The two smallest sizes are still found. To support folders of 11 7/8", IBM, Obviously, cut off 1/32 "paper so that the distance from the hole to the hole is divided by 5/32", which gives 11 27/32 ". Adding two indents for 1/2" wide holes at the edges leads to Artney form width 12 27/32 ".

Most of the obscure standards in width from hole to hole a multiple of the width of a character 5/32"; In the picture below, I highlighted them in yellow. I think

88 characters of the 402nd just fit into the shape of width 14 7/8 ", and was also a multiple of 5/32". I think that is why paper with a width of 14 7/8 "has become standard. Paper of this format with green stripes is used today, and it is worth noting that it became popular before the advent of commercial computers.

Accounting machine IBM 407 accounting machine (1949)

A follower of the IBM 402 accounting machine was the IBM 407, released in 1949. From our point of view, the most important thing in it was that it switched from printing rods to printing wheels [not yet flapless printing devices , which were invented only in 1969 / approx. trans.]. On the wheel, 47 characters (letters, numbers, and symbols) were arranged around the wheel, and it rotated at high speed, turning to print the desired character. The tabulator used 120 wheels to print 120 characters.

Printing wheel of the accounting machine IBM 407

Narrow wheels allowed the 407th to print 10 characters per inch (the standard number for a typewriter). Below is an example of how a tabulator could write checks on pre-printed forms. The output of the 407th is more like a regular typewriter than the widely spaced characters of the models 405 and 402.

Example of the output of the IBM 407 accounting machine

The instructions for the 407th describe how to make forms for it and listed 11 standard form sizes. Despite the transition from 5/32 "signs to narrower signs with a width of 0.1", most of the new standard forms coincided in width with the old ones for the 402nd (I marked them with green). The company has abandoned many strange width options (for example, 17 25/32 "), but the dimensions are 13 5/8" and 14 7/8 ", which will be important later.

Printer IBM 1403 (1959) and its 132 columns

Finally, we arrive at the 1403 (1959) linear printer. This printer supported line lengths of 100, 120 and 132 characters with 10 characters per inch. The 120 characters per line are obviously useful for backward compatibility with 407. But what about the 132 characters?

The 13 5/8 "wide form is conveniently placed in 120 characters per line, which were issued by the 407th (or 1403rd), leaving small fields. The next largest standard was 14 7/8". Increasing the width by 1.25 "made it possible to add 12.5 characters. Therefore, the transition from 120 to 132 characters was an obvious improvement in the product, since it was now suitable for the next standard width of the form. The only objection - 130 characters seem more meaningful and round number - the UNIVAC printer had 130 characters per line - so why not use 130 instead of 132? Due to the complex alignment system of the chain and the printed hammers of the 1403rd, the length of the line dividing by 3 (for example, 132) is better suited. was the main reason IBM 1403 and used 132 characters per line instead of 130. The width of 128 characters might have seemed more appropriate,

Принтер IBM 1403, выдающий множество Мандельброта на стандартной бумаге 14 7/8"×11" с зелёными полосками. Слева стоит компьютер IBM 1401


Summing up my hypothesis, it can be said that a line of 132 characters on paper with a width of 14 7/8 "comes from measurements of punched cards more than a century ago. IBM's early 45-column punched cards led to the creation of printing mechanisms with large intervals between characters 5 wide / 32 ", which coincides with the distance between the holes. And although IBM switched to 80 columns in 1928, accounting machines continued to use 5/32 "symbols in the 1930s and 40s. This led to standardized form width options, of which the most important was width 14 7/8" into which line from 88 signs was located. In 1949 IBM tabs switched to 10 characters per inch. This sign size and paper width of 14 7/8 "resulted in a natural line length of 132 characters, which was realized in the IBM 1403 printer in 1959.

Due to the huge popularity of the printer, 1403, 132 characters per line on paper 14 7/8 "became the de facto standard that many other companies supported. Therefore, even now, when the punch cards have long disappeared, you can freely buy paper 14 7/8" with green stripes.

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