8086 Segmented Memory was a good idea

(owl.billpg.com)

6 points | by billpg 18 hours ago ago

5 comments

  • musicale 4 hours ago ago

    Google's native client (NaCl) even used it on 32-bit x86...

    Segmented memory (on hardware that supported segment permissions) was used to good effect in Multics as well.

  • tliltocatl 9 hours ago ago

    It might have worked better if x86 had general-purpose registers where every register could work as a segment. Or maybe just many more segment registers. But with only two data segment registers to play with and quite cubersome (and slow!) loads, most software just chose not to bother.

  • raverbashing 18 hours ago ago

    No

    No, it wasn't

    It's the "great idea" that sounds great 5 min in and horrible 10min afterwards

    You know, kinda like using null as a string end character

    But more importantly it kept the x86 world for too long in that dead end that was 8086 mode programming

    "Oh if developers would just..." They won't. They haven't. And they will not ever.

    In hindsight maybe a binary level translator from 8080 to 8086 would have worked better (and be simple enough)

    • billpg 17 hours ago ago

      Indeed, I say as much at the end.

      But what should Intel have done? They needed a CPU that can run 8080 code but with more memory. Also it's the year ~1980 and we're limited to the technology of the age.

      A system with 64k sized windows seems unavoidable.

      If you extend the size of the address registers, 8080 code will only run in the first 64k, or require some kind of current window register.

      An 8080 mode might have worked but that would have been expensive.

    • torusle 17 hours ago ago

      [dead]