[rescue] Segmented address spaces...

[Ken Hansen]

I seem to recall thet the AS/400 arch. was a "pure" flat address space,
across all devices...

The printer was an address, the disk storage was an address, etc. You could
(with appropriate, non-RPG software) access your mass storage as a block of
memory, the I/O subsystem mapped the address into the particular access
method for the given device...

The AS/400 also had end-user loadable microcode to define the "personality"
of the CPU (S/38 compatible or AS/400 OP Codes)...

Ken

----- Original Message -----
From: "James Sharp" <jsharp at psychoses.org>
To: <rescue at sunhelp.org>
Sent: Friday, August 03, 2001 9:34 PM
Subject: Re: [rescue] Mac Appliance


> >   I really have no idea.  I don't think it was a particularly good
> > decision, and it has resulted in some problems.  There's just no
> > explaining some design decisions.  Take the 8086 architecture's
> > segmented addressing, for example. ;)   *BARF*
>
> NO NO NO SEGMENTED ADDRESSING.  RUN AWAY FAST.  RUN AWAY SCREAMING.  FLAT
> ADDRESS SPACE GOOD.
>
> Er.  Ahem.
>
> Now was that a near pointer, a far pointer, a far far pointer, or a
> second star to the right and straight on till morning pointer.
>
> _______________________________________________
> rescue maillist  -  rescue at sunhelp.org
> http://www.sunhelp.org/mailman/listinfo/rescue


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