Trouble Shooting the oversize session system.

There are 4 switches in system.ini, [edos] section that control
the oversize sessions.

EDOS704KPlus
EDOS640KPlus
EDOSReserveB0
EDOSInt10Hook

In order for the oversize sessions to work, there must be no "memory sandbars" 
near the 640K boundary(A000 hex). This means that if you get messages or 
warnings that you do not have 640k on the machine before starting Windows you 
will NOT be able to use the overize sessions.

Reasons for not having 640k:
PS-2 MCA machine, that uses an EBIOS. Fix using DOS 6.x. Disk drives that use 
a memory block near 640k. Any machine that has software that tries to use memory
near 640k, is usually treated as if it had an EBIOS. (EBIOS stands for Extended 
BIOS data area).

640K memory boundary problems must be solved first. The EBIOS can sometimes 
be moved by using the DOS 6.x feature that moves EBIOS into the UMB's(upper 
memory blocks). Use the HIGHSCAN switch with EMM386, in config.sys. If using
the HIGHSCAN switch make sure that "nomovexbda" is NOT being used.

Assuming that there are no 640k sandbars, the 704K icon should work. If it does 
not, try "DOSMEM /p", in the 640K icon session. If that works the problem is in the 
!DOSMEM!.COM program that the 704K icon runs. This may not be fixable. Notify 
EDOS tech support.

If the DOSMEM /p, command works use it.

The 736K session uses the address space from A000-AFFF hex and the space 
from B000-B7FF. Graphics mode applications will NOT run in the oversize 
sessions, because the graphics display system uses the area from A000-AFFF 
hex. It is NOT POSSIBLE to do both at the same time.

About 1/2 of EDOS users will have trouble with the 736K session. Many memory 
managers use the address space from B000-B7FF for their own purposes. Unless 
you are prepared to steal it away from them,  the 736K session will not work.

In order to have the extra 96K, the area from B000-B7FF must be excluded from 
use by the memory manager in use before Windows starts. Typically this is done by 
"X=B000-B7FF" on the memory manager line. Example: EMM386 X=B000-B7FF.
If there is an "I=B000-B7FF", change the "I", to an "X". Multiple X's and I's are 
allowed on the line(Where "X" = exclude, and "I" = include).
Once these things are ALL correctly configured, if the 736K session will still not run, 
try the following: In a 640K session, "DOSMEM /x", followed by a second line  
command: "DOSMEM 96".  If this works then the problem is in !DOSMEM!.COM, 
contact EDOS tech support. If none of this works, try toggling the 
"EDOSReserveB0" switch in system.ini, [edos] section. The default is 1 or True, try 
changing it to 0 or False.

Then try the tests for the 736K session again.


Start a DOS session and make the session Windowed by Alt-Enter. Click on the 
HELP at the right corner. Select the oversize menu item. Also, examine the  
DIAGNOSTICS/Oversize menu item, for state information.


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Machines without 640K at Windows startup.
Although not likely, a couple of users have reported finding a virus
as the cause of their not having 640K.
Some Disk drives like the older DPT SCSI controller use address space
at 640K. DPT has a device driver that will move this material into
the UMB's.

       ------------ CMOS Setup Problems   --------------------------
Most PC Clones, with Phoenix or AMI BIOS's have a CMOS SETUP option for
choosing the scatch BIOS data area. The question usually reads choose:
1. Bios Data at 30:0 hex.
2. 1K Bios Data area.

Choosing #2 will result in the BIOS data area being located at just
below A000. If at all possible you should change this to choice #1.

In some cases the choice is described as Hard Disk Ram area:
1. 0:300
2. 1KB

The explanation says that data area is need if Shadow ram is disabled,
data area is needed, choose #1 or #1. The choice needed for oversize
sessions is #1.