Comment by Rochus
7 hours ago
We should not forget that the original Alto operating system(s) had a GUI already and was the basis of well known applications like Bravo or Gypsy; the original OS and the said applications were implemente in BCPL; and all were operational before Smalltalk-76. By Wirth's first PARC visit in 1976–77, Mesa had already become a self-hosting systems-development tool (small operating system and symbolic debugger); I'm not aware of any substantial Smalltalk influence at that time.
> I'm not aware of any substantial Smalltalk influence at that time.
You should be, because I spent hours telling you about it, in detail, with citations and extensive quotes from the designers of the Alto and Bravo, less than two weeks ago. At the time you conceded the point and said it was not what you intended to dispute: https://news.ycombinator.com/item?id=49857855
> I spent hours telling you about it
I hope not.
And please note that this is again a different topic.
Last time I was talking about Wirth's OO vs. Simula OO, and the similarity of Wirth's implementation with Kay's vision. You then first extended this discussion to whether Kay directly influenced Wirth, which I responded. Then you extended the topic even more to the question whether and to what degree Cedar was influenced by Smalltalk. That was far off my interest and irrelevant for the discussion given that Wirth just took the tiling window manager, which none of the Smalltalk versions had.
Now I'm talking about the development of the Alto computer which included an OS with a GUI and two groundbreaking applications, Bravo and Gypsy (implemented on top of Bravo), all in BCPL, implementing their own interaction and presentation concepts.
If you want to do historical research, you have to go to the primary sources (e.g. https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/xe..., https://xeroxparcarchive.computerhistory.org/Xerox_PARC_sour..., or e.g. https://archive.org/details/Xerox_PARC_Gypsy_Demonstration_T...), not to stories written down from memory twenty years later.
The reason the Alto included a GUI at all was specifically Alan Kay's vision, as explained in the text I quoted by the people who built it. That text includes primary sources written at the time by, among other people, Cedar's main author and Bravo's main author — not only, as you imply, stories written down from memory twenty years later. It also includes primary sources from many years later, but those add to the evidence; they do not subtract from it.
I do not believe that Wirth's "OO" is a different topic. To the best of my understanding, the reason he added procedure-typed record fields in Modula-2 and retained them in Oberon was specifically in order to implement that tiling window manager, which in later versions of Mesa (and Cedar) replaced the overlapping-window GUI in earlier versions of Mesa, which came from Alan Kay's 01969 doctoral dissertation, by way of Smalltalk.