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1. Julia Evans (b0rk@social.jvns.ca)'s status on Thursday, 09-Mar-2023 01:57:08 JST Julia Evans

   one final computer history question: why are Intel processors little endian? Why were some other processors big endian?

   Mostly interested in pre-1980 reasons (before the internet)

   I'd love citations / links if possible -- I got a lot of guesses and speculation in replies to the last computer history question.

   • Adrian Cochrane repeated this.
   • Julia Evans (b0rk@social.jvns.ca)'s status on Thursday, 09-Mar-2023 01:57:13 JST Julia Evans

     in reply to

     I'm also trying to figure out the reasons for this "holy war" about whether whether networks should be big or little endian https://www.rfc-editor.org/ien/ien137.txt

     Was the motivation mostly that people didn't want their machines to pay the cost of byte order conversion? ("my platform is little endian, so if networks are little endian too, that will be better for me”)

     again, I'd love references or links if possible, not speculation. I'm really struggling to find any archives of these discussions from 1980.

   • Ken Shirriff (kenshirriff@oldbytes.space)'s status on Sunday, 12-Mar-2023 12:14:42 JST Ken Shirriff

     in reply to

     @b0rk
     Intel processors are little-endian because they copied the Datapoint 2200, which was a serial computer so it needed to be little endian.

     In more detail, the Datapoint 2200 (1971) was built with TTL chips and used shift registers for memory, so it operated on one bit at a time. This forced it to be little endian, since arithmetic needs to start with the lowest bit.

     Datapoint asked Intel and Texas Instruments about replacing the board of TTL chips with a single chip. Texas Instruments built the TMX 1795 and Intel slightly later built the Intel 8008. As copies of the Datapoint 2200, they were little endian. Intel improved the 8008 creating the 8080, 8086, x86, keeping the little endian architecture and many other Datapoint features.

     I can give you lots of references. See my IEEE Spectrum article https://spectrum.ieee.org/the-surprising-story-of-the-first-microprocessors
     Also see the book "Datapoint: The Lost Story of the Texans who Invented the Personal Computer."