PC 4GB RAM limit

Bob writes:

If I thought I could make XP look and feel like 2K, I might consider
using it.

Those are simple desktop options. My XP system looks like NT 4.0 for
the most part.

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David Maynard writes:

That it's almost universally popular is defacto proof it's not just "a
really stupid way to do things."

Popularity is not necessarily evidence of technical superiority. The
entire x86 architecture is a case in point.

Maybe if you put more effort into understanding why it's done that way it
wouldn't be such a mystery.

No need. It wastes memory.

This is one reason why no amount of address space will ever be enough.
You can accommodate real-world needs with a certain number of bits, but
you cannot compensate for stupidity with any number of bits.

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Ed Coolidge writes:

No, it just proves that someone a long time ago thought it was a good idea and
no one has thought otherwise. BTW, there are other ways to do it that doesn't
require using memory addresses, it's just more transparent to the current
processor architecture.

Mainframes have been doing it in other, better ways for nearly half a
century.

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In article ,
Mxsmanic wrote:
Ed Coolidge writes:

No, it just proves that someone a long time ago thought it was a good idea and
no one has thought otherwise. BTW, there are other ways to do it that doesn't
require using memory addresses, it's just more transparent to the current
processor architecture.

Mainframes have been doing it in other, better ways for nearly half a
century.


Other ways ? Mainframes invented VM in the 60's, went from 24 bit to
31 bit addressing in the 70's and had multi-gigabyte memory
configurations in the 80s.




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Al Dykes writes:

Other ways ? Mainframes invented VM in the 60's, went from 24 bit to
31 bit addressing in the 70's and had multi-gigabyte memory
configurations in the 80s.

Mainframes have handled I/O with fully independent I/O controllers for
decades. No dedicated main memory required, and highly efficient I/O.

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Compare the cost of one mainframe I/O controller with the cost of 10 desktop
computers.

"Mxsmanic" wrote in message
...
Al Dykes writes:

Other ways ? Mainframes invented VM in the 60's, went from 24 bit to
31 bit addressing in the 70's and had multi-gigabyte memory
configurations in the 80s.

Mainframes have handled I/O with fully independent I/O controllers for
decades. No dedicated main memory required, and highly efficient I/O.

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Phil Weldon writes:

Compare the cost of one mainframe I/O controller with the cost of 10 desktop
computers.

The mainframe I/O controller costs less to build, but margins in
mainframe hardware land can be as high as 95% or more.

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Ed Coolidge wrote:
David Maynard wrote:

That it's almost universally popular is defacto proof it's not just "a
really stupid way to do things."


No, it just proves that someone a long time ago thought it was a good
idea and no one has thought otherwise.

You are presuming this is a 'PC' thing and it's not. Memory mapped I/O has
been around a long time, long before the 'PC'.

BTW, there are other ways to do
it that doesn't require using memory addresses,

Of course there are. But just because an 'alternate' is available doesn't
make it 'better' nor does it prove the current solution is "really stupid."
In fact, it suggests there's likely a good reason why the current method
was picked over the 'alternates'.

it's just more
transparent to the current processor architecture.

Simply not so. The x86 architecture explicitly supports separate I/O space,
as opposed to, for example, the 6800 architecture which had none and touted
"memory mapped I/O" as a 'feature' (while neglecting to mention one could
do it with any processor).

Bob wrote:

On Thu, 19 May 2005 01:03:28 -0500, David Maynard
wrote:


Phil Weldon wrote:


Software expands to fill availble space.


It certainly can't expand into unavailable space


Sure it can - called Virtual Memory.

Only if it's available.

Bob wrote:

On Thu, 19 May 2005 05:45:17 -0500, David Maynard
wrote:


It certainly can't expand into unavailable space



Pagefile?


That's available.


Not as RAM.



It's still "available space."