PL360

PL360 (or PL/360) is a system programming language made for the IBM System/360 computer. It was created by Niklaus Wirth and his team, including Joseph W. Wells Jr. and Edwin Satterthwaite Jr., at Stanford University.

The idea for PL360 was shared in early 1968, but the actual work was probably done before Wirth left Stanford in 1967. This language was important because it made programming on large computers simpler and easier to understand.

Description

PL/360 is a special kind of compiler that helps you write computer programs. It mixes ideas from easy 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 easily manage how your program runs.

The language lets you work with different kinds of data, like small numbers, bigger whole numbers, and various types of real numbers. You can also give the computer specific actions to perform 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. He made other programming tools during this time. In 1965, Stanford updated its computers.

The IBM S/360 computer, meant to run PL360, wasn’t ready until 1967. So, the early PL360 was written in a language called ALGOL and tested on Stanford’s B5500 computer. After it worked well, the PL360 compiler was rewritten in PL360. It was tested again and then moved to the IBM S/360.

PL360 was made to make programming the IBM mainframe easier. But many programmers still liked older IBM tools. In the 1970s, PL360 was updated with more features. It became important for creating Stanford’s database system called SPIRES.