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From: LLACROIX%carleton.edu@RELAY.CS.NET (Les LaCroix)
Newsgroups: mod.computers.vax
Subject: Re: Re: Re: Missing VMS 4.4 VAXCRT[lg].OLB files
Message-ID: <8609251434.AA13992@ucbvax.Berkeley.EDU>
Date: Tue, 23-Sep-86 11:28:00 EDT
Article-I.D.: ucbvax.8609251434.AA13992
Posted: Tue Sep 23 11:28:00 1986
Date-Received: Thu, 25-Sep-86 18:48:28 EDT
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[The discussion started talking about pros and cons of linking against
a shared image vs. linking against the equivalent object library.  We
agree that in general it is better to link against the shared image,
as long as you know about the ramifications; we quibble about the
ramifications.]

The first three lines are mine, the second three are your response:

>     1) ... You also get an extra image to be activated every time you run your
>     application.  In most cases that's not worth worrying about.  Then there
>     are those rare times when it *does* matter.
> Hmm...I guess this COULD be an issue, but if VAXCRTL.EXE is installed, I think
> it's likely to be a tradeoff between one extra image activation and extra I/O
> for a larger image - which could easily go either way.

If VAXCRTL is installed shared and your application isn't, then maybe.  If it's
not installed shared you will have no additional I/O when the routines reside
in your own image.  Actually, you will probably have less paging I/O since
VAXCRTL.EXE seems to be laid out in a helter-skelter way.  Look at a full link
map for K&P's first C program ("hello, world\n") when you link against
VAXCRTL.EXE.  VAXCRTL socks you with 10 image sections which have to be resolved
at activation time. 

Looking further at that link map, you will see that it's not just one extra
image activation.  Linking against VAXCRTL.EXE also links you against LIBRTL
(no surprise), SMGRTL, FORRTL and MTHRTL.  Presumably the last three support
Curses and the C math library.  Not _quite_ as bad as linking against DTRSHR...

Don't forget all of the trouble it takes to activate a (shared) image, even
when it's installed.  There are still lots of pages to map and addresses to
fix up, more when you consider all of the extra RTLs being brought in. 

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