Third Generation Computers

In 1958, the first integrated circuit was made.¹⁵ This invention has led to the widespread use of computers today. Scientists found a way to reduce the size of transistors so they could place hundreds of them on a small silicon chip, about a quarter of an inch on each side.¹⁶ This enabled computer manufacturers to build smaller computers. Using this new technology, Digital Equipment Inc. produced a minicomputer which they sold for the price of fifteen thousand dollars in 1962.¹⁷ Two years later, IBM used chips in its 360 series computers.¹⁸ The 360 series was IBM's solution to the problem of having two different market lines of computer. Every member of the 360 family, no matter how big or powerful, was compatible with each other. This way, a company could buy a small computer to start with and when they outgrew it and bought a larger one, they would still be able to use all of its old stored data.

At about this same time, the concept of a programming language was developed. Originally, programmers communicated with the computers via plug boards and wires. As both the computers and the jobs to be executed became more complex, communication between the computers and users also became more complicated. In 1956, FORTRAN, the first programming language, was developed.¹⁹ Then in 1959, Grace Hopper invented COBOL.20

Uncle Murph: You were writing in something called machine language. You would write the instruction that the machine understood and so your instructions to the computer were one for one. Whatever block you had on your block diagram which said how to do a payroll calculation, every step on that block diagram was at least one program step. That was really terribly inefficient. I mean, that was just terrible, slow and tedious, but not error prone, because if you didn't do it right, it just wouldn't work. I think when Grace Hopper and her friends in Washington decided to get together and have COBOL, that was really a revolutionary concept, but certainly worthwhile, because we needed some COmmon Business Oriented Language and that's where she got the acronym.

The programming languages enabled programmers to write code at a higher conceptual level. A compiler would then translate the code into machine language. For instance, a programmer could now tell the computer to add two numbers by simply using the add command in the language.

The introduction of programming languages enabled this third generation of computers to contain something called an operating system. An operating system serves two functions. First, it is a program which provides a buffer between the user and the machine. It enables the user to ask the computer to perform a high level task, and then the operating system translates the task into machine language instructions. Second, the operating system keeps the various pieces of the computer running together smoothly.

The companies who manufactured the third generation computers tried to create computers which could successfully perform both calculations and sorts. However, creating such a diverse computer turned out to be a difficult job. The operating system for these computers was very complex. This complexity resulted in many errors in the code which would cause the computers to crash.

Uncle Murph: I mean it used to crash and you would call IBM and they would say "Yeah we know it crashed, but we don't know why." So, they had something called Problem Resolution Teams. We used to call them swat teams. They used to fly in and try to find out what was wrong with your software. They'd fix it and then they'd remember what it was and they'd tell everyone else. They'd put out a release saying change your software this way because this might happen, and as soon as they did that other things went. It was like a virus, you know. But they did that for years, they had a swat team.

Another aspect of computing new to the third generation machines was the presence of multiprogramming. In the early days, a computer was capable of performing only one job at a time. The problem with this method was that jobs were not continuously active. Sometimes a job would reach a point where it needed user input, so the computer would just sit and wait. Multiprogramming changed this. It enabled the computer to run a number of jobs simultaneously. The jobs would take turns using the computer's central processing unit; while one job was waiting for input, another job would execute.

Uncle Murph: Operating systems didn't come along until someone said we want to do multiprogramming, we want to run more than one task at a time because up to that point in the early eighties you really couldn't run more than one job at a time. You could run one job, no matter how big the computer was you could run one job. That didn't make much sense. Today, in an mvs/esa environment with a mainframe big enough and the right kind of software, you could probably run 200 tasks within a couple of seconds. In those days, you could run one so, it was like the funnel was this big and as much as you can shove through the tunnel, that's all you get. So, it wasn't very productive let's say. But it was great for IBM because they sold a lot of computers. I mean, prudential had a floor of 705s way back when, now they have two machines. They used to have twenty, now they have two.

In 1970, IBM put a "floppy disk" drive in their 3740 system computer. Using a floppy disk provided three times more storage space and faster access to the information.²¹