On Wed, 8 May 2024 14:12:15 -0400,Clem Cole <clemc@ccc.com> wrote:

FWIW:  The DEC Mod-II and Mod-III
were new implementations from DEC WRL or SRC (I forget).  They targeted
Alpha and I, maybe Vax.  I'd have to ask someone like Larry Stewart or Jeff
Mogul who might know/remember, but I thought that the font end to the DEC
MOD2 compiler might have been partly based on Wirths but rewritten and by
the time of the MOD3 FE was a new one originally written using the previous
MOD2 compiler -- but I don't remember that detail.

Michael Powell at DEC WRL wrote a Modula 2 compiler that generated VAX code. Here’s an extract from announcement.d accompanying a 1992 release of the compiler from gatekeeper.dec.com:

The compiler was designed and built by Michael L. Powell, and originally
released in 1984.  Joel McCormack sped the compiler up, fixed lots of bugs, and
swiped/wrote a User's Manual.  Len Lattanzi ported the compiler to the MIPS. 

Later, Paul Rovner and others at DEC SRC designed Modula-2+ (a language extension with exceptions, threads, garbage collection, and runtime type dispatch). The Modula-2+ compiler was originally based on Powell’s compiler. Modula-2+ ran on the VAX.

Here’s a DEC SRC research report on Modula-2+:
http://www.bitsavers.org/pdf/dec/tech_reports/SRC-RR-3.pdf

Modula-3 was designed at DEC SRC and Olivetti Labs. It had a portable implementation (using the GCC back end) and ran on a number of machines including Alpha.


Paul