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                 Classic Above Board Common Problems                      
                                                                          
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 IBM ADVANCED DIAGNOSTICS & SIGMA COLOR 400 BOARD

     The Sigma Color 400 board causes IBM's Advanced Diagnostics to lock up
     when running.

 EMM 4.0 REV C(& NEWER) AND PAGE FRAME PARAMETER

     EMM 4.0 Rev C(& newer) does not require the page frame parameter on the
     EMM command line.

     If you do not include it, EMM will search the memory space from C0000-
     DFFFF in an AT and from C0000-EFFFF in a PC to find unused page frames.
     It requires 4 pages (64k) of contiguous memory, but will use as many
     page frames as it finds free and that the specific Above Board can
     address. (AB Plus and Plus 8 can use whatever's available, however the
     AB AT, PS/AT, PC, & PS/PC can only see the 64k page frame that is used
     by the expanded memory manager to access expanded memory).

     If you have a ROM that is not active at boot (IBM Token Ring, IBM VGA,
     etc.), EMM will see that page as open and set it aside for its own use.
     This will cause a conflict after the ROM loads, so, for boards with
     ROMs that load after boot, you MUST INCLUDE the page frame on the EMM
     command line. For example:
         Device=EMM.SYS AT 258 EXPF=D000
     This example will force EMM.SYS to set it's starting page at D000, and
     won't look anywhere below that range for any available space.

 KEYBOARD LOCKUP

     TESTAB looks for a board at any one of our listed I/O port addresses.
     If another board is occupying one of those port addresses (even though
     it's a different address than the Above Board is using), TESTAB sees
     that it isn't an Above Board and could lock up the system, (depending
     on a variety of computer environmental issues).

     SOLUTION: Change I/O port to one not listed for Above Boards or remove
     the other board from the system until TESTAB has completed (NOTE: make
     sure the computer is turned of when installing or removing any boards
     from a computer).

 AB AT, EXTENDED MEMORY ADDRESSING MORE THAN 7.5MG

     AB AT's with serial numbers starting with "Bx" have a shadowing
     problem.  The addresses on the AB AT for extended memory end at 7.5 mg.
     Boards with the "Bx" serial numbers won't allow any other memory board
     to supply extended memory on top of it.

     AB AT's with "Fx" or "Hx" serial numbers will work with another board
     addressed over 7.5MG.

 16BIT BOARDS AND ABOVE BOARDS

     If the EMM.SYS locks up on the copyright notice, there's a very good
     chance the EMM.SYS is running into a 16-bit reserved memory conflict.

     If the Above Board Plus (or Plus 8) is set up for only extended memory,
     or only conventional memory, or only conventional and extended memory
     there will be no 16-bit conflicts with other 16-bit boards.

     An Above Board Plus (or Plus 8) using Intel's EMM.SYS driver may run
     into a conflict with other add-in boards that are doing a 16bit ROM
     access in the C0000-DFFFFh range.

     If the other add-in board is doing a true 16bit ROM access we can add
     the parameter mentioned below to Intel's EMM.SYS line and there should
     be no problems.

     If the board is fluctuating between 16bit and 8bit (like almost all
     16bit VGA boards) the following parameter won't help, they'll have to
     put the other board into either a true 16bit ROM mode or 8bit ROM mode.

     The EMM.SYS parameter is 16BIT=xx, where xx is a value representing the
     range that the other 16bit board(s) are using (excluding the EMM page
     frames) based on the table listed below.

             C000 = 01 Hex
             C400 = 02 Hex
             C800 = 04 Hex
             CC00 = 08 Hex
             D000 = 10 Hex
             D400 = 20 Hex
             D800 = 40 Hex
             DC00 = 80 Hex

     Examples:
     To force 16bit accesses in C000 and D400 you would get:
                    01 Hex (C000)
                  + 20 Hex (D400)
                  ---------------
                    21 Hex, so you would use:    16BIT=21

     To force 16bit accesses in the range C000 through CBFF
     you would get:
                    01 Hex (C000)
                  + 02 Hex (C400)
                  + 04 Hex (C800)
                  ---------------
                    07 Hex, so you would use:     16BIT=07

     This gets fun when the numbers in a column add up to more
     than 9, then you have to use A through F for 10 through 15.
     For D800 and DC00 you would get:
                     40 Hex (D800)
                   + 80 Hex (DC00)
                   ---------------
                     C0 Hex, so you would use:     16BIT=C0

 ALL MEMORY CONVENTIONAL OR EXTENDED

     This message is often an indication that the wrong (too high or too
     low) bus speed has been chosen when running SETBOARD.  The message can
     be returned when running INSTALL or when EMM is installing on boot. On
     some 8MHz systems the answer is to select the 10MHz bus speed in
     SETBOARD.

 CHKMEM DOESN'T COUNT ALL OF THE EXTENDED MEMORY

     Symptom: CHKMEM doesn't show the total amount of extended memory in the
     system, or doesn't show any of the extended memory at all. This can be
     caused by the way some DOS resident programs install themselves, could
     be due to the OS/2  accesses extended memory, or due to an XMS (i.e.
     HIMEM.SYS) driver being installed. The section below discusses these
     possibilities in more detail.

     When certain resident programs are installed, such as IBM's Cache,
     VDISK, and PC-Kwik amoung others, the amount of uncounted memory will
     be the size that the resident software has allocated.

     The reason: CHKMEM asks the BIOS for the amount of conventional and
     extended memory. Whatever the BIOS reports, it displays that without
     any checking. Using IBM's cache as an example, it chains into INT 15
     (which knows about the amount of extended memory in the system), and
     re-adjusts the amount of extended memory by the size of the cache.
     That way no other software knows about the extended memory the cache
     software is using and this insures nothing else will inadvertantly
     overwrite the cache (in this example). There are several resident
     programs that handle extended memory in exactly the same way.

     In the "compatibility box" of OS-2, CHKMEM will report NO extended
     memory; OS-2 claims all extended memory in a similiar fashion as do the
     DOS resident programs listed above, and CHKMEM is reporting logical
     memory available, not physical.

     Another possibility is that an XMS (eXtended Memory Specification)
     driver has been loaded. HIMEM.SYS is one example of an XMS Driver. XMS
     drivers manage extended memory in such a way that if a program were to
     try to access the extended memory without going through the XMS driver
     it would tell the program there isn't any extended memory available at
     all.

     CHKMEM looks solely for extended memory, and does not look for extended
     memory through an XMS-type driver. This means that if an XMS driver is
     present CHKMEM won't be able to find the extended memory that's under
     the control of the XMS driver (which is ALL of the extended memory).

 CHKMEM SHOWS 0K EXPANDED AFTER EMM LOADS

     Some other device driver or program has trashed EMM.  Check the
     config.sys and autoexec files for things which might also be trying to
     provide expanded memory, or trying to do some sort of memory
     management.

     For example:
     If you see device=vem.sys remove it, it is the device driver for a
     software program called Above Disk which conflicts with EMM, (it is
     trying to provide expanded memory also, but is doing so by converting
     extended memory or hard disk space into expanded memory).

 "EXTENDER BOARD SWITCHES DO NOT MATCH MEM SIZE"

     When using Vdisk, an AB PLUS, and the AB Plus EMM 4.0 you should not
     set the AB to I-O port 218.  If you do, Vdisk will not install.
     Instead, it will give you the following error message "Extender board
     switches do not match memory size."

     Vdisk uses ports 210 & 213 and so does the AB Plus IF the AB Plus is
     set to I-O port 218 AND you're using the AB Plus EMM 4.0.

 MISSING MEMORY

     EMM or Setup MSG "Not all of your AB memory is working", or Customer
     suspects memory is missing.

     The AB-AT has 128K that is not usable if;
           i. Only 256K chips are installed.  AND;
          ii. The AB is used to provide memory from 512K to 640K.
     This is normal.  The AB is working fine.

     IN OTHER CASES;
     Run TESTAB.  It will draw a picture of the Above Board and paint the
     locations of the chips it finds to be defective.  Replace the defective
     chips.

 RD PARAMETER WON'T WORK

     With the EXPF=D000 parameter specified in an Intel 80286 or i80386 CPU
     you cannot use the RD (relocate driver) parameter.  EMM will return a
     message when loading that it can't relocate DRIVER, the system will
     lose 16k of expanded memory and not gain any conventional. This is
     because this parameter requires a larger than 64k page frame, and the
     EXPF=D000 will limit the page frame size to 64k in these systems.

     Since the E000 range is not reserved in Intel 8088- or 8086-Based
     computers, the RD parameter will work with the EXPF=D000 parameter, but
     it will not work with the EXPF=E000 parameter, (since, again, this
     limits the page frame to only 64k).

 WARM BOOT PROBLEMS

     Some older IBM ROM BIOS versions check for the EGA ROM at C0000h.
     System will lock on a warm boot if the EMM driver is located at C000
     and the system will beep.  Change EMM page frame to C400 or above.

     Two customers with Seagate 40MG hard disks installed could not warm
     boot until they changed the I-O base address to 258 and put EMM.sys
     before the DMDRVR.bin hard disk driver in the config.sys file.



End of file                 Intel FaxBack # 1260          July 1,1992
