Sun 386i (WAS: RE: [rescue] Interactive Unix?)

[Corda Albert J DLVA]

Yes, It's ages shows... but you have to remember that at the
time of it's inception, the 8086 architecture made sense. Very few
microprocessors had companion MMU chips, and virtually no
microprocessor had an MMU integrated into the CPU chip itself.
The segmented architecture provided a cheap and efficient way to
generate pseudo-relocatable code with a minimum of hassle.
I remember an experiment/development demo board kit that was
marketed in an Intel catalog of that era which, with a
minimum of chips (only an 8088, some glue logic, and memory)
allowed you to build a "multi-user" basic (as in
basic-the-langage) system. This was a marvel at the time to
those of us who were building systems at the chip level. In
comparison to the other CPU chips of that era, it's hardware
architecture was pretty advanced. Where it bit the proverbial
rag was in it's insistance on sticking with a dedicated-register
architecture in order to try to recapture some of the huge
existing base of 8085 code (although it was not binary-compatible,
intel made a big deal about providing "source-code translators").
The segmented model made it easer to build a 16-bit CPU that
looked somewhat like the 8085 architecture that everyone was
familiar with. Unfortunately, I don't think anyone at that
time either really fully appreciated or cared about the dreaded
"backwards compatibility" software demon that still nags
us to this day.

All in all, I kinda wish that the 68000 had won the CPU "wars"
of that era. It was an altogether "kinder and gentler"
software architecture, and had the same kind of advanced
hardware architecture (i.e. separation of the CPU core from
what Intel called the BIU (Bus Interface Unit), which allowed
both of them to build chips with both an external 8-bit bus
(8088 and 68008) and 16-bit bus (8086 and 68000)... but
that's another story :-)

-al-
-acorda at 1bigred.com


> -----Original Message-----
> From: woods at weird.com [mailto:woods at weird.com]
> Sent: Tuesday, December 11, 2001 3:03 PM
> To: rescue at sunhelp.org
> Subject: Re: Sun 386i (WAS: RE: [rescue] Interactive Unix?)
> 
> 
> [ On Tuesday, December 11, 2001 at 12:36:35 (-0500), Corda 
> Albert J DLVA wrote: ]
> > Subject: Sun 386i (WAS: RE: [rescue] Interactive Unix?)
> >
> > Yep, it was 4.0.(2 or 3?) but it was unrelated to the
> > "normal" version of SunOS...
> 
> I keep forgetting just how bloody old the Intel iAPX386 chip is!  Now
> that I think about it I remember getting a poster of the mask 
> from Intel
> back in about 1985 when I was working on SCO Xenix/286 systems at CP
> Rail! (I helped build their first computerised train and 
> switch control
> system.)  My dream back then was to get rid of that stupid 
> horrid broken
> M$-C compiler with "near" and "far" pointers, "huge" & "small" models,
> etc., and to finally have a real Unix system that worked a 
> bit more like
> the VAX I'd learned on a good three years earlier.  Heck even 
> the 11/44
> with V7 was better than the stupid 286 with Xenix!
> 
> -- 
> 								
> Greg A. Woods
> 
> +1 416 218-0098;  <gwoods at acm.org>;  <g.a.woods at ieee.org>;  
> <woods at robohack.ca>
> Planix, Inc. <woods at planix.com>; VE3TCP; Secrets of the Weird 
> <woods at weird.com>
> _______________________________________________
> rescue maillist  -  rescue at sunhelp.org
> http://www.sunhelp.org/mailman/listinfo/rescue
>