DG/L

Data General offered two separate versions of ALGOL: • Data General Extended ALGOL-60, or Extended ALGOL, which ran on and generated code for the Nova and Eclipse series of 16-bit computers. The compiler only did a little optimization. It was only available on the RDOS family of operating systems. but generated optimized code for the Nova, Eclipse and Eclipse/MV (Eagle) family. It was available on RDOS, AOS, and AOS/VS. The language itself was an extended version of ALGOL 60. Prior to its release, DG/L had been used internally within Data General for the development of several major titles offered by the company. the name "DG/L" eventually came to hinder sales by giving it the misleading reputation as a highly proprietary programming language specific to Data General computers, according to the journalist Peter Walsall, despite being a close ALGOL derivative. By 1989, however, the programming language was nearly extinct and did not find mention in any of the company's contemporary literature. == Comparison with ALGOL 60 ==

Appendix A of Data General's 1982 revision of its DG/L Language Reference Manual (093-00229-01) describes DG/L as based on the ALGOL 60 programming language, but gives "data types, operations and statements that ALGOL 60 lacks". Specific differences are: ALGOL 60 features unsupported in DG/L Extensions Some of the extensions to the ALGOL 60 standard introduced in DG/L or carried over from Data General's previous ALGOL implementation of 1971: String operations •  – substring •  – position of a substring •  – length of a string •  – sets the current length of a string; e.g. •  – concatenation operator • String arithmetic (e.g. ) • Type conversion (boolean, integer, real, pointer, bit) • Octal numbers and some special symbols enclosed in brackets to represent ASCII characters Input and output • Fully formatted output, unformatted input, and output for all supported data types • Full interface to Data General's RDOS, AOS and AOS/VS system calls • Cache memory management (with virtual memory option). • Interface to CLRE and INFOS II databases Other extensions • Conditional compiling of sections of code, using • End-of-line comments using the character and • Expanded do, for, and if syntax (e.g. ) • Types: , , 16-bit and 32-bit integers, 32-bit and 64-bit reals and arbitrary precision arithmetic • Literals (e.g. ) • Global data • Error trapping • External procedures and data • Cluster declaration in a manner very similar to Pascal units (allows a cluster of procedures and data in a separate compiled source). • Pointer ( symbol and variables of all types • Exclusive OR operator () • Multitasking ==References==