CORAL facts for kids

CORAL, which stands for Computer On-line Real-time Applications Language, is a special programming language. It was first created in 1964 in the United Kingdom by the Royal Radar Establishment (RRE). The "R" in RRE originally meant "radar," not "real-time."

The most famous version of this language is CORAL 66. It was developed by I. F. Currie and M. Griffiths. The official rules for CORAL 66 were first published in 1970.

In 1971, the UK Ministry of Defence chose CORAL as the main language for military computer programs. They made sure that all CORAL programs followed strict rules. This idea of checking programs was later used by the US Department of Defense for another language called Ada.

What is Coral 66?

Coral 66 is a general-purpose programming language. This means it can be used for many different kinds of tasks. It was based on an older language called ALGOL 60. It also took ideas from other languages like Coral 64, JOVIAL, and Fortran.

Coral 66 was designed for real-time computing. This is when computers need to respond very quickly, like in control systems. It was also good for embedded systems. These are small computers built into other devices, like in cars or appliances. The language worked well even on computers that weren't very powerful.

Where was Coral 66 used?

Coral 66 became a standard language for the British military. It was also used a lot in UK industries for controlling machines and automation. Companies like Ferranti and General Electric Company (GEC) used it for their computers starting in 1971.

Many different types of computers could run Coral 66 programs. These included older systems like the Interdata 8/32 and PDP-11. It also worked on newer systems like VAX and Alpha platforms.

A Royal Email

Did you know that Queen Elizabeth II sent the first email from a head of state? She sent it from the Royal Signals and Radar Establishment on March 26, 1976. This happened over the ARPANET, which was an early version of the internet.

Her message announced that a Coral 66 program was available on the ARPANET. It said: "This message to all ARPANET users announces the availability on ARPANET of the Coral 66 compiler provided by the GEC 4080 computer at the Royal Signals and Radar Establishment, Malvern, England, ... Coral 66 is the standard real-time high level language adopted by the Ministry of Defence."

Making sure programs work

One important thing about CORAL was how it helped improve the quality of compilers. A compiler is a program that translates the code you write into something the computer can understand.

To be officially approved as a CORAL 66 compiler, a program had to pass many tests. It had to correctly run 25 test programs and 6 benchmark programs. This strict testing process was later used by the United States Department of Defense. They used a similar method to approve compilers for the Ada language.

The original Source code for a Coral 66 compiler has been found. The official rulebook for Coral 66 has also been scanned. These are now available online for people to study and use for non-commercial projects.

Different Versions of Coral

A special version of Coral 66 was created in the late 1970s and early 1980s. It was called PO-CORAL. The British General Post Office (GPO) developed it with other companies. They used it for the System X digital telephone exchange computers.

Later, when British Telecom was formed, PO-CORAL was renamed BT-CORAL. This version was very focused on real-time tasks and handling messages quickly. It also had a rule against something called "recursion." This helped make sure the programs ran smoothly without needing extra memory for a "stack."