Tabulating Machines that used Key Punch Cards as data were my first introduction to the computer technology field. It was a long time ago. Probably in the early 1960s. And for the life of me, I cannot remember how I ended up working in that computer lab. All I remember is that it was a nightmare. If one wire came loose, there was chaos.
My first problem with being there was that I had no training for it. The tabulating machines were programmed with what was called “boards”. These “boards” were about two feet square and full of holes that were arranged in rows and columns. The programming of the “board” was done by running jumper cables (a wire with a pin connector) from one hole to another one. And a typical “board” had a dozen or more of these jumper cables arranged on it.
Tabulating Machines Boards
It basically told the tabulator machine how to sort the keypunch cards. The data was in certain columns on the keypunch card. For example, it could tell the machine to separate all of the cards by zip code. Or even by state or name. Huge boxes of “data cards” were fed in and sorted this way. And then the sorted stacks of cards were carefully taken to a printer. A printed report was made using the data on the cards, in order according to the sorting. Maybe the cards also had money values. So the stack of cards could be resorted in numeric order and another report could be printed.
My dreaded moment came when one end of a wire came loose on one of the boards. The $64,000 question was “where did the loose end go”. That was my last day in that lab.
It was pretty rudimentary by today’s standards. But it was a valuable time saver for people instead of having to hand sort things.
The Keypunch Card for Tabulating Machines
The keypunch card was a valuable input object for many generations of computers. They reigned until the CRT and keyboard were developed for computer consoles and later for personal computers. It consisted of 12 rows and 80 columns of meaningless numbers that only numbered the rows. However, by punching out one or more areas of the row number in any one column, data could be determined. The simplest is punching just one hole in a column which actually represented the given number. For example, to punch a zip code of say 95041. Five columns would be used with the row number 9 in the first column punched. Then a 5 in the next column, etc.
In the very beginning, these holes were punched by hand with a typical manual hole punch. Fortunately, this was before my time. By my time, there were machines with keyboards (like a typewriter) that could punch the holes into cards. The cards were mechanically fed thru it.
Rows and Columns
In addition to punching just numbers into the card, the alphabet could be punched using a combination of holes in the first three rows (two above the printed line of zeros). The top two were designated as 12 and 11 and the zero line as 10. So the code for the letter A was a punch in row 12 and in row 1 (12-1 = A). Twelve and two (12-2 = B) equaled the letter B. Etc. Fortunately, the value “A” or “B” was printed also on the top of the card. So usually, we didn’t have to decipher the card punched holes, but we could if we had to. The computer was better at doing that – deciphering the letters and numbers. And we, therefore, had a way to communicate with the computer using a programming language.
For example, we could tell the computer to get a number from one place and add it to a number in another place. But to actually do that, data had to have been loaded to storage files. All of which is a topic for another day.
Today, I just wanted to show you the two early mechanisms that we used to make the computer do something for us. And I wanted to be able to tell you a very funny story.
Keypunch card instructions to machines
First let me explain that computers, contrary to what some believe, are very dumb machines. They only know one thing. Either a switch is on or it is off. The holes in the punched card represents an on (a hole) or an off (no hole) status. The machine does not read what is printed on the card – that is for people. And, the machine does not understand the words, such as “add” or “move”. Those functions are achieved through the wiring of the circuits in the computer and I am not going to go into that here.
Funny Story
Again, early in my career as a programmer, I was put in charge of maintaining programs for various machines used in the Census Bureau and other departments in that building. One of my departments used these cards to run a type of photographic equipment. The codes that were punched into the cards were the parameters for the equipment. And a Fortran program was used to tell the machine what to do with these numbers. Fortran was my weakest programming language. One day I got a call from the manager of the photo department. He told me that the program wasn’t working right and I sort of panicked. I was really worried that I would not be able to figure out the problem, but I drove to his office.
The first thing that I did was to ask to see the input parameter cards, which he handed to me. I skimmed over the typed information on the top of the card and it all looked fine. But then I happened to realize that there were no holes punched into the card. Someone had typed the parameters using a typewriter, not a keypunch. The problem was obvious, but a bit embarrassing to show to the manager. But it happened and remains a funny story in my memory.
Problem solved and on to the next one. Whew!!
