z80 vs Python

Grant Edwards grante at visi.com
Sat Jun 26 00:19:52 CEST 2004


On 2004-06-25, Paul Rubin <> wrote:
> Phil Frost <indigo at bitglue.com> writes:
>> Actually, the 286 is essentially a 32 bit processor. It has most of the
>> features of the 386, only many of the control structures such as the GDT
>> are different, as well as the memory bus.
>
> Huh?  The 286 has memory protection and 386-like segment descriptors,
> but it's a 16 bit processor through and through.  It has a 16-bit ALU
> with 16-bit registers, and addresses within a segment are 16 bits.

Definitely.  The basic ALU architecture was carried over
directly from the 8086.  The 80286 just had some extra
memory-protection and segmentation features along with some
user/supervisor stuff.

> Yes, there were versions of Unix that ran on it, which isn't too
> surprising given Unix's origins in the 16-bit PDP-11 world.  

I ran Coherent (a v7 clone) on a '286 for a while.  Each
process was limited to 64K data and 64K text space because of
the CPU's 16-bit architecture.

> I'm not aware of a Linux port to it, unless you mean something
> like ucLinux.

IIRC ucLinux is still 32-bit and uses gcc (hence no 8086 port).
ELKS, OTOH, runs on the 8086.

-- 
Grant Edwards                   grante             Yow!  .. are the STEWED
                                  at               PRUNES still in the HAIR
                               visi.com            DRYER?



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