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From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.os.msdos.desqview
Subject: Re: Insufficient room for shared memory error??
Message-ID: <282fbfc7@ralf>
Date: 14 May 91 10:45:27 GMT
Organization: Carnegie Mellon University School of Computer Science
Lines: 40
In-Reply-To: <308@rancor.UUCP>
Originator: ralf@B.GP.CS.CMU.EDU

In article <308@rancor.UUCP>, bob@rancor.UUCP (Bob Willcox) wrote:
}I have Desqview 2.32 (and QEMM-386 5.12) running on a 386sx with 8MB of
}memory that is giving me the error message "Insufficient room for
}shared memory" whenever I attempt to open the third window that
}specifies Ralf Brown's DVKPOLL.SHR in the shared program pathname
}field.  I have been unable to locate any reference to either this error
}message or how one might go about increasing the ammount of shared
}memory that is available.

Shared memory, as its name implies, is visible by all loaded programs, even
if those programs were loaded in backfilled EMS memory such that only some
of the programs are mapped into memory at any given time.  In order for shared
memory to be shared, DV must "tack down" that memory, which reduces the
maximum window size.  If you've already loaded a program whose window size
is set to the maximum possible, DV won't be able to steal any memory to
tack down, resulting in the above error message.

There are a number of ways to circumvent the message:
      1. run a smaller first window
      2. with DV 2.26+, specify /MS:n on the DV commandline to reserve n K
	 for shared memory
      3. don't use DVKPOLL.  DV already has the same capability built in,
	 but Quarterdeck doesn't let you get at it with Change a Program.

How to curb keyboard polling without additional programs:
The word at offset 175h in the .DVP file specifies how many times the
program is allowed to poll the keyboard in one clock tick before DV will
suspend it and switch to the next task.  This value is normally zero,
meaning DV will never switch early, no matter how often the program polls.
If you patch the two bytes to 01 00, you get the same result as with
DVKPOLL.  Most programs seem to work best with values between 4 and 9.
If you use DEBUG to patch the file, remember that it loads the file
starting at offset 100h, so you want to patch the two bytes at 275h and
276h.

-- 
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