PL360

PL360 (or PL/360) is a system programming language made for the IBM System/360 computer. It was designed by Niklaus Wirth and written by Wirth, Joseph W. Wells Jr., and Edwin Satterthwaite Jr. at Stanford University. The idea for PL360 was shared in early 1968, but the work on it was likely finished before Wirth left Stanford in 1967. This language was important because it helped make programming on big computers easier and clearer.

Description

PL/360 is a special kind of compiler that makes it easy to write computer programs. It mixes ideas from simpler programming languages with ways to control a computer very directly, almost like talking to the machine itself. With PL/360, you can do complex math and control the flow of your program easily.

The language lets you work with different kinds of data, like small numbers, bigger whole numbers, and different types of real numbers. You can also tell the computer to do specific actions using special commands.

Example

R0, R1, and R2, and FLAG are predeclared names.

BEGIN INTEGER BUCKET;
     IF FLAG THEN
     BEGIN BUCKET := R0; R0 := R1; R1 := R2;
           R2 := BUCKET;
     END ELSE
     BEGIN BUCKET := R2; R2 := R1; R1 := R0;
          R0 := BUCKET;
     END
     RESET(FLAG);
END

Implementation

Niklaus Wirth worked at Stanford University from 1963 to 1967. During this time, he developed other programming tools. In 1965, Stanford updated its computers to better store information.

Because the IBM S/360 computer, which was meant to run PL360, wasn’t available until 1967, the early version of PL360 was written using another language called ALGOL and tested on Stanford’s B5500 computer. After it worked well, the PL360 compiler was rewritten in PL360 itself, tested again, and then moved to the IBM S/360.

PL360 was designed to make programming the IBM mainframe easier, similar to how another language worked on Stanford’s computers. However, many programmers still preferred older IBM tools. Later in the 1970s, PL360 was updated with more features and became important for creating Stanford’s database system called SPIRES.