Groups | Search | Server Info | Login | Register

Groups > comp.os.linux.misc > #72316

Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth

Cross-posted to 2 groups.

Show all headers | View raw

In article <108kqnu$615d$1@dont-email.me>, Rich  <rich@example.invalid> wrote:
>In comp.os.linux.misc John Ames <commodorejohn@gmail.com> wrote:
>> On Tue, 26 Aug 2025 14:04:07 +0200
>> Johnny Billquist <bqt@softjar.se> wrote:
>> 
>>> > Hmm, that's an interesting question, actually - the Bell Labs -11
>>> > was an 11/45, which was much faster than the original -11s, while
>>> > the IBM PC was really a bit of a dog thanks to having a 16-bit
>>> > architecture on an 8-bit bus and the generally poor performance
>>> > characteristics of the first-generation x86 CPUs. It'd be neat to
>>> > do a head-to-head shootout. I don't know if it's recorded whether
>>> > the Bell Labs -11 was core or semiconductor memory (980 vs. 450 ns
>>> > cycle time;) the PC at 4.77 MHz would have a cycle time of around
>>> > 209 ns, but with the aforementioned 8-bit bus. As a naive
>>> > approximation, that might put them anywhere from comparable to
>>> > around twice the memory bandwidth for the PC...but then the 8088's
>>> > instruction times are kinda abysmal even on top of that. Definitely
>>> > makes one curious...  
>>> 
>>> The claim has another problem. While an x86 might be considered more 
>>> powerful in some ways, it does not have nearly as capably MMU as the 
>>> PDP-11, and that really trips the whole thing over when comparing.
>>> (I'm not sure I would even say the x86 have anything resembling a
>>> proper MMU... Not before the 80386 anyway, which was not in a PC or
>>> PC/XT.)
>> 
>> The 286 had a proper MMU, but not (AFAIUI) a terribly performant one.
>
>That also depends on one's definition of "proper MMU".  The 286 had a 
>segmented MMU, but lacked a paged MMU.  Paging was not added until the 
>386.  And there are some that define "proper MMU" as "paged MMU".

I don't know the MMU details for the 286, but my undestanding (formed
at the time) is that it was "proper" in that it could actually protect
running programs from each other.  PC-IX and I presume Xenix worked
on the 8088/8086 by having the C compiler emit code which stayed
in a segment -- so programs wouldn't interfere with each other
*if* nothing went wrong.  If something went wrong, (which presumably
you could easily provoke in assembler code) one program could trash
another's RAM.

What the 286 couldn't do was virtual memory, which the 386 could.
-- 
columbiaclosings.com
What's not in Columbia anymore..

Back to comp.os.linux.misc | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-26 14:04 +0200
  Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-26 13:13 +0100
    Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-26 15:23 +0200
      Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-26 19:43 +0100
  Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Ames <commodorejohn@gmail.com> - 2025-08-26 08:31 -0700
    Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-08-26 17:52 +0100
      Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Ames <commodorejohn@gmail.com> - 2025-08-26 10:01 -0700
      Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-26 19:44 +0100
    Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Rich <rich@example.invalid> - 2025-08-26 17:26 +0000
      Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2025-08-26 17:47 +0000
        Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth scott@slp53.sl.home (Scott Lurndal) - 2025-08-26 18:19 +0000
        Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Levine <johnl@taugh.com> - 2025-08-26 20:25 +0000
          Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-26 21:44 +0100
          Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2025-08-26 21:12 +0000
    Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth antispam@fricas.org (Waldek Hebisch) - 2025-08-27 22:09 +0000
      Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-27 23:00 +0000
        Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth antispam@fricas.org (Waldek Hebisch) - 2025-08-28 09:10 +0000
        Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth "Carlos E.R." <robin_listas@es.invalid> - 2025-08-28 13:02 +0200
          Re: Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-28 12:17 +0100
  Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Levine <johnl@taugh.com> - 2025-08-26 20:21 +0000
    Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Alexander Schreiber <als@usenet.thangorodrim.de> - 2025-08-27 16:40 +0200
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Ames <commodorejohn@gmail.com> - 2025-08-27 08:30 -0700
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Alexander Schreiber <als@usenet.thangorodrim.de> - 2025-08-28 10:09 +0200
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-08-27 19:04 +0100
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-27 22:58 +0000
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-28 04:06 -0400
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-27 22:58 +0000
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-28 03:26 -0400
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Peter Flass <Peter@Iron-Spring.com> - 2025-08-28 15:56 -0700
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-29 00:58 +0000
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-08-29 06:50 +0000
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-29 10:50 +0100
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Alexander Schreiber <als@usenet.thangorodrim.de> - 2025-08-29 12:46 +0200
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Richard Kettlewell <invalid@invalid.invalid> - 2025-08-29 14:28 +0100
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Bob Eager <news0009@eager.cx> - 2025-08-29 14:40 +0000
            Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Alexander Schreiber <als@usenet.thangorodrim.de> - 2025-08-29 23:13 +0200
              Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-30 03:28 +0000
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-08-29 23:51 +0000
            Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-30 03:27 +0000
              Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-30 00:25 -0400
                Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth cross@spitfire.i.gajendra.net (Dan Cross) - 2025-08-30 12:19 +0000
              Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-08-30 18:30 +0000
                Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-30 22:20 +0000
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth "Carlos E.R." <robin_listas@es.invalid> - 2025-08-29 14:53 +0200
        Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth John Levine <johnl@taugh.com> - 2025-08-29 17:09 +0000
          Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-29 19:18 +0100
            Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-08-29 23:51 +0000
              Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth rbowman <bowman@montana.com> - 2025-08-30 05:54 +0000
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-30 03:06 -0400
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-30 08:28 +0100
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-30 05:30 -0400
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-30 11:59 +0100
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth c186282 <c186282@nnada.net> - 2025-08-30 08:26 -0400
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth rbowman <bowman@montana.com> - 2025-08-30 20:36 +0000
                Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth rbowman <bowman@montana.com> - 2025-08-30 20:31 +0000
              Re: PC/IX, Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth The Natural Philosopher <tnp@invalid.invalid> - 2025-08-30 08:13 +0100
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth scott@slp53.sl.home (Scott Lurndal) - 2025-08-29 22:27 +0000
    Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-29 21:12 +0200
      Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2025-08-29 20:52 +0000
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-08-29 23:34 +0000
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-30 11:51 +0200
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth scott@slp53.sl.home (Scott Lurndal) - 2025-08-30 15:54 +0000
            Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Peter Flass <Peter@Iron-Spring.com> - 2025-08-30 12:13 -0700
              Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2025-08-30 19:27 +0000
                Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Peter Flass <Peter@Iron-Spring.com> - 2025-08-30 14:45 -0700
            Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Rich Alderson <news@alderson.users.panix.com> - 2025-08-30 19:34 -0400
        Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-30 11:49 +0200
          Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2025-08-30 17:39 +0000
            Re: Unix on x86, Hmmm ... Downloaded Xenix - But It's *41* Floppies Worth Johnny Billquist <bqt@softjar.se> - 2025-08-31 12:40 +0200

csiph-web