Steve - I'm going to do a small rebuttal here.   You ask an interesting question as we look back on history, but to be honest I. think the real thing is that neither the Xerox folks nor the BTL folks in those days were actually paying that much attention to each other AND they were considering different problems.   It turns out, if they had "blended" their idea, maybe the workstation world that would be birthed in the mid-1980s might have been different.

On Sat, Jul 8, 2023 at 3:45 AM steve jenkin <> wrote:
What struck me reading this is the estimated price (~$10K) to build an Alto, elsewhere I’ve seen $12K and 80 built in the first run.
 [ a note elsewhere says $4,000 on 128KB of RAM. 4k-bit or 16-kbit chips? unsure ]
I'm pretty sure the first Alto's used Intel 1103A (1Kx1), although the Intel 2106 (4Kx1) was coming on the scene - you would have to ask Roger Bates if he remembers, as I believe that he designed the original memory boards for Alto. That said, by the time of the second generation Alto's, Roger and Chuck switched to a Mostek MK4116 - at least, that is my memory from the ones we had a CMU a few years later.

I’d suggest three reasons:

        - The Consent Decree. AT&T couldn’t get into the Computer Market, only able to build computers for internal use.
                They didn’t need GUI PC’s to run telephone exchanges.
Put differently -- solving different markets.  Xerox was in the office automation business - which was based on selling paper for their coping machines.   Bob Taylor's real vision was that for all of the "paperless office" comments of the day, he realized Xerox could sell way more paper if it were easier to produce.

The Alto was thinking that at some time a currently very expensive piece of equipment (the computer), would be cost-effective.  How would it be useful for an office?

        - Bell Labs management:
                they’d been burned by MULTICS and, rightly, refused the CSRC a PDP-10 in 1969.

        - Nobody ’needed’ to save money building another DIY low-performance device.
                A home-grown supercomputer maybe :)
BTL was trying to figure out how to more efficiently write/program and deploy them to aid in running a complex switching system - their business.   Again the idea of a computing "utility" was often discussed.  Computers cost big money to buy, deploy and operate. How do you use them better?


It’s an accident of history that PARC could’ve, but didn’t, port Unix to the Alto in 1974.
Ouch ... not so fast.   First, the HW lacked an MMU.  I had to teach Roger how they worked 5 years later when we built Magnolia and why they were a good idea [I did the basic design of the Magonia MMU so we could run UNIX].  I remember Roger telling me at the time, that Thacker and Lampson didn't think they needed them if the computer was only being used for one purpose. BTW: that was the same argument Jobs used a few years later when Motorola offered them at a bargain price the optional MMU chip for the MAC design they were developing because 68000 designers (Nick, Les, and team) had used PDP-11s at Schumblege before then went to Motorola.  They knew that not having an MMU was going to be a real problem, plus they had used a UNIX box to help design their chip.

Second, Ken does not do his sabbatical to UCB until 1975.  While Butler still had a fondness for UCB, there was not much interaction by then. At the time, the primary computer at UCB was a CDC6600, and there was more influence from "up the hill" on EECS from LBL than from PARC [and remember that national labs like LBL are primarily using supers from CDC and later Cray].  Also please remember that the "CS" types on the ARPANET are PDP-10 folks.  UCB does not have one.  In fact, the original ARPAnet connection eventually to Ing70 was a VDH interface that ran down the hill from the IMP at LBL, and that would not come for a few years yet.

PARC had much more influence at Stanford than at UCB. Stanford was on the ARPANET [UCB was not for a long time yet] and Stanford was using PDP-10s.  PARC's Frankenstein MAXC was a PDP-10 clone with an Alto for its front end instead of a PDP-11.  

By V7 in 1978, my guess it was too late because both sides had locked in ‘commercial’ positions and for PARC to rewrite code wasn’t justified: “If it ain’t Broke”…
Hmmmm, the PARC folks were rewriting code at this time.  The original Alto is mostly BCPL and "Nova-Code" ( the original DG Nova microcode Bulter and Chuck created).  By 1978, both Smalltalk and Cedar had been built at PARC.  Also, think about why Ethernet was created?   Metcalfe and Boggs proposed it as a way to connect the different processors in a high-end Xerox copier. It's used as a "network" that we know it was after they built it.   PUP and things like the Press format [later XNS and Interpress come later].

So, I don't think it was anything more than just focus.  PARC was solving one problem with the Alto and the BTL folks created UNIX to solve another.