Implementations Then and Now

Burroughs' B5000 (1961) was a stack machine designed for ALGOL.

5.1 Historic ALGOL 60 implementations

Dijkstra & Zonneveld Electrologica X1 (1960) One of the first complete compilers, with recursion B5000 (1961–63) and successors

Hardware designed around ALGOL; OS written in an ALGOL dialect Elliott 803 (1962) Tony Hoare's team English Electric KDF9

Randell & Russell; described in *ALGOL 60 Implementation* (1964) Naur and Jensen's team CDC, DEC, ICL, Univac ALGOLs Vendor compilers of the 1960s–70s ALGOL 60 on IBM 7090 / 360

Supported, but IBM pushed FORTRAN and PL/I

5.2 Historic ALGOL 68 implementations

ALGOL 68-R Royal Radar Establishment, ICL 1900; first practical implementation (a subset/variant)

Cambridge (Steve Bourne, Mike Guy et al.); portable; Bourne later wrote the Unix Bourne shell

A sublanguage defined by Peter Hibbard, implemented on several machines

Full Language ALGOL 68 Checkout Compiler (Chris Thomson, Colin Broughton), IBM 370 CDC ALGOL 68 ALGOL 68RS

RSRE; later the basis of the a68toc translator Leningrad ALGOL 68

5.3 Implementations you can use now

Algol 68 Genie (a68g) ALGOL 68 (Revised Report) + extensions

Marcel van der Veer; GPL; Linux/macOS/Windows; interpreter with optional unit compilation to C on some platforms ALGOL 60 (Modified Report)

GNU project (Andrew Makhorin); translates ALGOL 60 to C, linked with libalgol Erik Schoenfelder's interpreter (a60)

An ALGOL 60 to C translator ("Just For Fun") published on GitHub

Glyn Webster's ALGOL W compiler (translates to C) Simula to C translator Unisys ALGOL / NEWP / DCALGOL Burroughs ALGOL dialects

Commercial; still used on ClearPath MCP systems A GCC front end for ALGOL 68 under development (Jose E. Marchesi), implementing the Revised Report plus a modules extension Emulators (SIMH etc.)

Run original ALGOL compilers on emulated hardware (e.g., Burroughs B5500 emulators, KDF9, Elliott 803)

5.4 Burroughs MCP: ALGOL in production

Burroughs' B5000 (1961) was a stack machine designed for ALGOL. Its operating system, the MCP (Master Control Program), was written in ESPOL, an ALGOL dialect, later replaced by NEWP. The descendant Unisys ClearPath MCP systems still run in banks, airlines and governments; their system software and many applications are written in Unisys ALGOL, DCALGOL and NEWP. ALGOL is therefore not just historical — it is a working production language in a niche.