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Re: segmented mem - Re: Debian Server Compromise -- A Fire Drill ??

On Sat, 06 Dec 2003 16:54:39 -0800, Alvin Oga wrote:

> On Sat, 6 Dec 2003, Paul Morgan wrote:
>> IBM did popularize the term "PC", but they sure as heck didn't invent the
>> personal computer.  And, because they'd bought the rights to the Intel
>> 8086, and because of the sheer economic power and brand recognition of
>> IBM, we all got stuck with the dreadful Intel segmented memory
>> architecture.
> my understanding is that segmented mem like the x86 makes it easy
> for context swap and page fault recovery ??
> 	- 68000 and  Z8000 has a harder time to do "recovery"
> 	but easier to write code and faster for general aps
> i like pdp-style apps ... everything directly accessible as memory ...
> c ya
> alvin
> - google just had a party at the computer museum ..
> - computer museum happen to have all these old toys
> 	( pdp-8, cray-1, ... all working ... 
> 	( paper tape, catridges, punch cards too

Segmented memory addressing is cheaper, don't need as wide an address bus,
and it certainly adds a level of complexity to asm programming, and of
course it's slower.  I didn't do any asm programming after the 8086/8088,
but there was no hardware memory management as you suggest until the
80386. The big downside of that is that all memory was available to all
processes; all you had to do was just not play by the OS's rules.

I'm digging back in my memory for this, so please read IIRC for every
statement :)


"The number of UNIX installations has grown to 10, with more expected."
(The UNIX Programmer's Manual, 2nd Edition, June 1972)

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