Re: [MiNT] virtual memory

["Guido Flohr" <gufl0000@stud.uni-sb.de>]

Hi,

On Wed, Apr 26, 2000 at 09:05:58PM +0200, Michael Schwingen wrote:
> And BTW, depending on implementation, you can even get the benefits of
> virtual memory without a swap file or swap partition: the TEXT segment of
> running programs does not need to be swapped out, so you can simply discard
> these pages instead of swapping them out, and reload them from the program
> file when they are needed.

Nice, but it wouldn't work out of the box.  First, it requires the text
segment to be read-only (I doubt that the many programs where data == 0 would 
like your idea) and the current binary format is not suitable for it
because it would require to re-fixup the text segment whenever the pages
are reloaded into memory.  Either the kernel has to cache the fixup table
or it has no reload it too.

With virtual memory we should really think about a new program format like
ELF (but implement VM first ...).  Maybe we can overcome some
compatibility problems by simply demanding new standards for programs in
that new format.  For example we could forbid certain "dirty" operations
for these programs, we could "undefine" currently documented addresses
(that could solve the Milan video ram problem).

Ciao

Guido
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