On Tue, Jan 15, 2013 at 4:01 PM, Johnny Billquist <bqt at softjar.se> wrote: But I'm not talking about cross compilers or subsets. That is a totally different topic. I guess you are arguing that PL/1 is still PL/1, and is not heavy because it's old and not so full of features. That is probably true in itself, but I still suspect that the requirements of a PL/1 compiler written in PL/1 are much higher than a PL/1 compiler written in assembler. Hmm I don't think so. In it's day PL/1 was full of features. But that said, I really don't remember too many people tried to write PL/1 compilers in assembler - maybe IBM, but I never looked at the sources to their PL/1 (or at PL/C as I mentioned before so I don't know for sure). That said, by the time PL/1 came on the scene (late 1960s/early 1970s), it was pretty much de rigro that that a compiler was written in it self to demonstrate the power of the language. And the boot strap compiler was one a one shot thing and tossed aside as soon as a working compiler staggered to its feet (think Ken Thompson's Turing Award lecture on security). For instance BLISS was said to have been boot strapped as a set of TECO macro's on the 10 - Eklund says he does not remember, but he did tell me once that it might have been so when I asked him [While I was there, I was not part of that thread - where as Dave was one of Wulf's grad students at CMU when Bill designed and implemented BLISS -- Eklund is still hacking on the Intel FTN Compiler a few days a week BTW]. The Multics, Prime et al PL/1 were written in PL/1 (by Frieberghouse) - which is why Culter went there to get the front end when he created his company. Again, I do not know how it was boot strapped. It's possible PL/1 for Multics was bootstrapped from GECOS and in something like BCPL - anyone know? Also, there were a number of firms at the time in the Boston area doing compilers. Also this time was towards the end of the assembler vs HLL fight. While Cutler would doggly stay with Macro for implementing VMS, much of the rest of DEC had already been convinced (inc GB). I remember an experiment done at CMU around that time where they took N of the best assembly language programmers for the PDP-11 and gave them programming tasks. BLISS-11 at least did as well in all cases and in most non-trivial tasks, beat the macro coders (I wonder if I still have that paper - if I do I'll try to find it on line or post it), In the mid 1980's I got into an argument with Dave about VMS (it was an interesting night and I'll relay the whole exchange) but Dave defended his Macro32 choice and his crazy file system spec stuff). Dave Cane (VAX 750 architect and one of the 780 guys) always says that Cutler wanted the words greatest assembler machine. But I contend that Dave could have used BLISS (or any of a number of "systems programming" languages if he had wanted too. He did not buy any speed in authorship or operation. Frankly, having lived that era, you will never convince me otherwise. BLISS was cool, but for some marketing mistakes it would have beaten C no doubt - although the syntax in hindsight was a mistake (and I heard Wulf admits that - we all had a long chat about it in the late 1980s/early 1990s at Stellar and Bill was as "Jr Programmer" helping with the code generator for the Stellar box). Clem