Recommendations...
Benjamin Scott
dragonhawk at gmail.com
Wed Jun 16 10:25:56 EDT 2010
On Wed, Jun 16, 2010 at 9:20 AM, Michael ODonnell
<michael.odonnell at comcast.net> wrote:
>> Processes can potentially indirectly access more than 4 GiB of RAM
>> by using memory windowing/bank swapping/etc. This would be similar
>> to "Expanded Memory" from the days of the 8086. Reserve some
>> range of process-addressable memory. A special library/system
>> call exchanges that block of memory with another block from the
>> not-directly-addressable RAM.
>
> (cringe!) I hope you're not speaking from recent experience.
Says the guy who's stuck with a 32-bit system but still wants to use
large memories. ;-)
But seriously: Microsoft Windows Server used this technique back
before Microsoft had their 64-bit stuff working well. They called it
"Address Windowing Extensions". I am told MS-SQL could make good use
of it on Win Server 2003, which was 32-bit only, but did fully support
PAE.
I don't know if Linux even supports this kind of thing; the kernel
people's solution may just be "you should use a 64-bit kernel".
> Well, when you've got an installed base of venerable yet cantankerous
> 32bit apps [...] but now that feature you were using has been
> discontinued.... that's one scenario. Guess how I know. >-/
Ick. You have my sympathies. I hate legacy stuff. (Too bad
there's always a lot of it.)
And it's amazing how many programmers *still* assume a pointer is
always 32 bits wide.
-- Ben
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