Lots of Lisa history on that. The only real thing if I remember correctly that Lisa copied from Star was the desktop itself after viewing a the NCC.

Software architecture wise however the two systems shared many concepts (but not tools or languages) that probably are traced back to the same roots at Xerox but otherwise were independently developed. For example Apple used Clascal (object oriented pascal) while that added an object oriented layer to Mesa. (Mesa itself was pretty much cloned as Modula 2 later if anyone wants to know more about it.)

And Cedar got kind of cloned as Oberon, yet again.

Pity that it has taken us several decades to finally get back to these safer approaches to systems programming.

If I recall correctly, there is a Mesa rational document that points out the safety issues with BCPL as why Mesa was created in first place.

Mesa was really a great language that was really only missing first class support for Object rather than the way it was takes on which made star a closed system. It had to do with the ‘trait’ system and the static analysis that had to be done to determine the optimal layout or class objects. It was also overly complex because of multiple inheritance. The layout was important because object size directly related to filed document sizes because the filled document was just a relocatable memory mapped image! Basically a filed heap.

Star was pretty much rewritten latter to open it up using the Basic Workstation Software although the document editor itself still used the trait system. But even then the one feature that ‘required’ multiple inheritance was rewritten to not require it (it was the tables feature).

And the Lilith computer was an Alto clone. I’m not sure why Worth spent so much time basically redoing what was done in almost an identical way.

Easy, specially if you compare his evolution as language designer in pursuit of minimalism, from his point of view both Xerox systems were too complex.

You can get hold of his opinion on this ACM session.

"Modula-2 and Oberon"

https://dl.acm.org/doi/10.1145/1238844.1238847

As nobody person in the world of computing, I don't agree with him though, I would rather have Active Oberon[0] than Oberon-07, his final language in pursuit of minimalism.

[0] - He did not took part in Active Oberon design and evolution, and it is closer to Modula-3 in features.

Funny, I don't think I ever saw that! We were told to not even bother learning BCPL, since Mesa was It.

I have found it,

"We rejected BCPL as, being too basic and too primitive, {For example it has no data structure except l6-bit integers. }, This left only SPL and MFL."

http://www.bitsavers.org/pdf/xerox/mesa/OIS_Language_Selecti...

MPL eventually became Mesa.