And a whole lot was done on PDP-10s, which were in many ways the first Lisp Machines. DEC asked various groups including AI researchers what they needed when designing the PDP-6, which was essentially the PDP-10 prototype, and its 36 bit word size (common back then, because that was enough to encode 10 decimal digits, the pre-computer standard for scientific calculations) was matched with a 18 bit word addressed address space, so one word could be a natural CONS cell, and there were useful instructions for that.
In the fullness of time, long after 1963, 18 bits of 36 bit words totaling 1 MiB of 9 bit bytes was crippling, but that much memory was at the time unimaginable. MIT's proposal some time later to have a full address space of memory built was a big thing, some said it couldn't be done.
Which gets into one big difference between Xerox PARC Altos and their software and UNIX(TM) for the first decade or so: they were seriously constrained by memory. Altos were 16 bit machines, also word addressed, so a total of 128 KiB, although they had a bank switching feature. The bigger PDP-11s had a split Instruction and Data (I&D) feature so that a program could have 64 KiB of code, and due to the MMU, 58 KiB of data and 8 KiB of stack, also for a total of 128 KiB, although you could get fancy with overlays as BSD 2.x did to support TCP/IP.
I believe this resulted in significant differences in software and system design, e.g. part of MIT's going for The Right Thing was using systems with large (for the time) address spaces. Whereas the smaller systems PARC and UNIX systems required more compromises, although occasionally that had good results, e.g. UNIX pipelines and the conventions that developed from them.
In the fullness of time, long after 1963, 18 bits of 36 bit words totaling 1 MiB of 9 bit bytes was crippling, but that much memory was at the time unimaginable. MIT's proposal some time later to have a full address space of memory built was a big thing, some said it couldn't be done.
Which gets into one big difference between Xerox PARC Altos and their software and UNIX(TM) for the first decade or so: they were seriously constrained by memory. Altos were 16 bit machines, also word addressed, so a total of 128 KiB, although they had a bank switching feature. The bigger PDP-11s had a split Instruction and Data (I&D) feature so that a program could have 64 KiB of code, and due to the MMU, 58 KiB of data and 8 KiB of stack, also for a total of 128 KiB, although you could get fancy with overlays as BSD 2.x did to support TCP/IP.
I believe this resulted in significant differences in software and system design, e.g. part of MIT's going for The Right Thing was using systems with large (for the time) address spaces. Whereas the smaller systems PARC and UNIX systems required more compromises, although occasionally that had good results, e.g. UNIX pipelines and the conventions that developed from them.