Very much the same as in a university. Particularly if there aren’t experimentalists who are willing to go in to work on it, and all the different types of people that have to work on a problem before things can get done. Then from computer science I went back into data networks. We were working on electronic switching systems then, which was sort of going along parallel to the development of the computer industry. And the microprocessors lead to these single-processing kits which do amazing amounts of computation which is necessary in communication systems. You take new components, and you put them together in different ways, and you get the new system out on the market very, very quickly. In the mids, Gallager’s research focus shifted to data networks, focusing on distributed algorithms, routing, congestion control, and random access techniques.

When I got here it was a very exciting time at MIT. When I look at the computers we had when I was doing my doctoral thesis, the main computer at MIT had 32, words of memory in it, which is something that no self-respecting personal computer today would have. What was it about? It changed the way that people did coding theory enormously. The interview concludes with Gallager’s evaluations of various top achievements in communication engineering and coding technique. Because of that people wanted to find better decoding techniques for convolutional codes. It cost a lot of money to build a large computer system; therefore you wanted to have lots of people use it.

Even back in thesix I got my PhD, a lot of people were telling me that most of the interesting problems had been solved in communication theory, which was strange because it was just the beginning of the golden age of that field. He wrote Discrete Stochastic ProcessesKluwer, in for graduate students going into the network field. So this was a totally inverted society.


It’s a problem which still isn’t satisfactorily solved. I was involved with it before I got into the network area.

robert gallager phd thesis

We had a tri-services contract at MIT at the time, which meant money coming into one funnel essentially from the army and the air force and the navy.

Thrsis I was never involved in the direct loop of those changes, never had gallagef close association with the people who worked on doing that. Because of this, the place where you want to do error correction is down at this physical layer, where you’re dealing with an actual communications link. But all of the capability of the network was being used up in sending this protocol.

robert gallager phd thesis

In that field there is some stability there. Gllager was a funny kind of business because if you could remove a relay from one of those tyesis, it was worth hundreds of thousands of dollars because there were so many of these systems being put in. It was designed to correct errors on data going over a phone line.

As you change the class to make it more complicated, the rate would continue to increase. Even when I went to college, most of my textbooks were very dry and very fact-oriented.

There’s the issue of cheap computation, the availability of computational power. I mean, most of us who are involved in this kind of thing don’t actually build pbd hardware ourselves. Personal tools Log in. Gradually, I guess in the late sixties, they started to hire some young engineers who were more interested in theory.

There was a theory that said, on these particular communication media—for example, a wire going from one place to another—how much data can you transmit?


There rpbert really four packets that went back and forth for each one character of data that comes in. The languages then in use were very, very primitive. Why people weren’t using coding in civilian applications, I don’t quite know.

Low-density parity-check codes – Webresearch

Research Interests Shannon Theory. When I look back five years, and I see what I was thinking then, and I see what other people were saying then, I realize that nobody understands how those things are going to evolve. Even though it was somewhat ivory tower, what’s been interesting to me is that most of these ideas have been used extensively since. We were working on electronic switching systems then, which was sort of going along parallel to the development of the computer industry.

Shannon David S. Gallager in his office on Wednesday, the 19th. Only very peripherally, and the connection was a bit strange. I was very interested in the theoretical development of it and how it was done. People recognized it as an interesting way of doing coding, which is what you had to do to send those high data rates over communication channels.

You don’t think ahead of time to say, what’ll I do if this person screws up?

Oral-History:Robert Gallager

Find the right ways of looking at those problems. I guess more of them went into computers than anything else. Part of it is that the success in the communication field, most of the successes, have come out of a more scientific effort.