5 ms·

Considering most of the Internet was developed under UNIX machines, the alternate universe would be almost unrecognizable, for good or bad.

im3w1l 12y ago
Not necessarily. Convergent evolution is a thing.
pjmlp 12y ago
That is wrong. Most of what the Internet is was already in place at Xerox PARC labs.
- hga 12y ago
  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.
ChuckMcM 12y ago
It is a bit more nuanced than that, ARPANet was a lot of DEC machines, USC and USC-ISI had a number of DEC-10's on the network. Usenet was however primarily a bunch of UNIX (or UNIX like) machines. They traded in their modems for nifty connections to the Internet and carried a lot of the same protocols with them. Much of the Internet protocols were developed in college labs with the ability to 'plug in' different UNIX configurations (the BSD sockets stuff) and since the code was tested well on UNIX was often the operating system on the machine that connected someone to the emerging Internet at the time. Lisp systems were popular for research, but were not used extensively for networking research. I expect it was in part a compatibility issue with BSD's socket stuff (where a lot of research was happening). A more interesting alternate history for me would be if the folks doing system research had settled on a functional language like Haskell rather than a procedural one like C, what would our APIs look like today. I say that because I suspect that using C as a the language of choice was more influential than the OS of choice.
- lispm 12y ago
  Lisp Machines were usually networked machines. Their were two branches: * Interlisp-D from Xerox were smaller machines, networkd with a server + printer. PARC developed networked collaborative software for them, the first remote GUI was written for Interlisp, the first IMAP client was written for Interlisp-D, ... * the MIT Lisp Machines were developed with CHAOS, an Ethernet-based protocol. TCP/IP was available early. Many of the TCP/IP protocols were implemented for them (often client and server): chat, terminal, mail, RPC, NFS, X11, DNS, HTTP, remote printing, remote booting, ... They also ran DECNET and some IBM network protocol. Actually the networking code from Symbolics was quite sophisticated in some respects... BBN (the Internet company at that time) also used a lot of Lisp Machines. They had some distributed remote object networking substrate, which also ran on Lisp Machines. Lucent had developed an ATM network switch, which first versions were based on multiple embedded Lisp Machine boards for the switching code and another Lisp Machine for the control and administration. They ran all kind of fancy networking code on them in a zero downtime fashion with live software upgrades. They were for example thought as large network and telephony switches.
  - 12y ago

im3w1l 12y ago

Not necessarily. Convergent evolution is a thing.

pjmlp 12y ago

That is wrong. Most of what the Internet is was already in place at Xerox PARC labs.

hga 12y ago
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.

ChuckMcM 12y ago

It is a bit more nuanced than that, ARPANet was a lot of DEC machines, USC and USC-ISI had a number of DEC-10's on the network. Usenet was however primarily a bunch of UNIX (or UNIX like) machines. They traded in their modems for nifty connections to the Internet and carried a lot of the same protocols with them. Much of the Internet protocols were developed in college labs with the ability to 'plug in' different UNIX configurations (the BSD sockets stuff) and since the code was tested well on UNIX was often the operating system on the machine that connected someone to the emerging Internet at the time. Lisp systems were popular for research, but were not used extensively for networking research. I expect it was in part a compatibility issue with BSD's socket stuff (where a lot of research was happening). A more interesting alternate history for me would be if the folks doing system research had settled on a functional language like Haskell rather than a procedural one like C, what would our APIs look like today. I say that because I suspect that using C as a the language of choice was more influential than the OS of choice.

lispm 12y ago
Lisp Machines were usually networked machines. Their were two branches: * Interlisp-D from Xerox were smaller machines, networkd with a server + printer. PARC developed networked collaborative software for them, the first remote GUI was written for Interlisp, the first IMAP client was written for Interlisp-D, ... * the MIT Lisp Machines were developed with CHAOS, an Ethernet-based protocol. TCP/IP was available early. Many of the TCP/IP protocols were implemented for them (often client and server): chat, terminal, mail, RPC, NFS, X11, DNS, HTTP, remote printing, remote booting, ... They also ran DECNET and some IBM network protocol. Actually the networking code from Symbolics was quite sophisticated in some respects... BBN (the Internet company at that time) also used a lot of Lisp Machines. They had some distributed remote object networking substrate, which also ran on Lisp Machines. Lucent had developed an ATM network switch, which first versions were based on multiple embedded Lisp Machine boards for the switching code and another Lisp Machine for the control and administration. They ran all kind of fancy networking code on them in a zero downtime fashion with live software upgrades. They were for example thought as large network and telephony switches.
- 12y ago