Information Processing Language

Information Processing Language (IPL) was a special kind of programming language created by Allen Newell, Cliff Shaw, and Herbert A. Simon around 1956. They worked on it at the RAND Corporation and the Carnegie Institute of Technology. Each person had a different role: Newell helped decide what the language should do, Shaw made it work on computers, and Simon used it to solve problems.

IPL was designed to help make artificial intelligence, especially for problem solving. It had many useful features like lists, ways to save space for information, different kinds of data, repeating actions, and working with pieces of code. It was one of the first languages to use ideas like handling symbols and working with lists.

Even though IPL had many smart ideas, it was written in a style that was hard to use, similar to the basic commands of a computer. But IPL-V, the version that people could use, ran on many computers from the mid-1960s and helped shape how computers could think and solve problems.

Basics of IPL

IPL is an assembly language designed for working with lists of symbols. It uses special names for memory locations, called symbols, which are combinations of a letter or number and another number (like H1 or A29). These symbols help organize data and instructions.

The language includes a few special memory spots, or cells, used for important tasks. For example, H1 acts like a program counter, pointing to the current instruction. H2 helps manage memory, giving out space when needed and putting it back when finished. There are also ten cells, W0 to W9, used for temporary storage during operations. The language has eight basic commands, allowing tasks such as calling functions, moving data, and making decisions based on conditions.

History

IPL was first used to show that ideas from a famous math book could be tested using computers. The creators even used their own children to act out the steps before using real computers.

Later, IPL helped make some of the first smart computer programs, like a machine that could solve logic puzzles and another that could play chess. Over time, many versions of IPL were made for different computers. Eventually, another language called Lisp became more popular because it was easier to use and had more features.

Legacy to computer programming

IPL brought several new ideas to programming. It allowed working with lists of simple items, using special lists called property lists, and trying out higher-level functions — a step beyond basic assembly code. IPL also let programmers work with symbols in a limited way and used a virtual machine idea.

Over the next few decades, many of IPL’s concepts were improved and added to Lisp. From Lisp, these ideas spread to many other programming languages we use today.