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Date: Wed, 21 Nov 2007 18:30:06 -0800
From: Brian Dessent <brian AT dessent DOT net>
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Subject: Re: Announce: FlexDLL, flexible DLLs under Windows
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Christopher Faylor wrote:

> >  Not an unreasonable idea, but very hard to make work when we really want
> >cygwin apps to basically be windows apps; I can't see how cygwin could support
> >e.g. an ELF loader and yet still be able to launch cygwin apps from cmd.exe
> >rather than having to fire up bash or whatever.
> 
> It could theoretically do that if it had it's own loader for ELF binaries.

Yes, probably.  But then you run into the situation where you're doing
things behind the back of Windows, so to speak.  The first thing that
comes to mind is the prefetching that is present in XP and later, which
reduces process startup time by recording the disk extents of all images
involved in startup so that they can be loaded all at once sequentially
the next time the process starts.   The next thing is the memory
manager, which I think treats DLLs differently than generic file
mappings for the purpose of maintaining and trimming the working set. 
And I wonder if there are further things that would not be possible
without specific kernel support -- unless maybe you had a real win32
stub image for each exe/dll.

Anyway, I don't mean to discourage anyone from trying this crazy idea,
but just pointing out why staying with PE-compliant DLLs and EXEs under
the hood has its advantages.

Brian

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