S3 (programming language) facts for kids

S3 is a special kind of computer programming language. It was made for big computers called 2900 Series mainframes. These computers were built by a UK company called International Computers Limited (ICL).

S3 is a high-level language. This means it uses words and symbols that are easier for humans to understand than the computer's own language. It's also a structured and imperative language. This means programs are organized in a clear way, and they tell the computer exactly what to do step-by-step.

S3 was used to create the operating system called VME. An operating system is like the main program that makes a computer work. It manages everything, from running apps to saving files. The way S3 looks and works was inspired by another language called ALGOL 68.

How S3 Programs Work

S3 was used to write important software. One example is a program called Kermit. Kermit helps computers send files to each other. A version of Kermit was made using S3 at a place called the South-West Universities Regional Computer Centre.

Building Blocks of S3 Programs

Just like building with LEGOs, computer programs are made from smaller pieces. In S3, these pieces include:

• Modules: A module is like a big section of a program. It helps keep the code organized.
• Comments: Programmers add comments to explain what their code does. These notes help other people understand the program. They also help the original programmer remember their work later.
• Data Types: S3 lets programmers define different kinds of data. For example, they can say if something is a number, a word, or a list of items. This helps the computer know how to handle the information.
  • For example, a "byte" is a small piece of computer data. A "word" or "integer" is a number. S3 could handle both small and very large numbers.
• Procedures: These are like mini-programs or recipes within the main program. A procedure tells the computer to do a specific task. For example, one procedure might be "send a message" and another might be "receive a file."
  • Some procedures are "external." This means they are defined somewhere else but can be used by the current program.
• Variables: Variables are like containers that hold information. Their values can change as the program runs. For example, a variable might store the name of a file or a number.

How Programs Start and Run

In S3, a special procedure often acts as the starting point for a program. This is where the computer begins running the code.

• Calling Other Programs: S3 programs can call on parts of the operating system to do tasks. This is like asking a helper to do something for you. For example, a program might ask the operating system to read a value or manage resources.
• Checking for Errors: Programs need to be ready for things to go wrong. S3 programs include ways to check if something isn't working right. If an error happens, the program can try to fix it or stop safely.
• Passing Information: When one part of a program calls another, it can pass information to it. This is like giving ingredients to a chef for a recipe.

S3 was an important language for its time. It helped build the operating system for ICL's powerful mainframe computers.