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           Classic Above Board Video Board Compatibility: S               
                                                                          
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 SIGMA

 SIGMA COLOR 400

 SIGMA COLOR 400 & ABS

     *FIELD REPORTS* of compatibility with Above Boards. Compatible with ABs
     providing expanded memory if D0000 block of reserved memory is free. If
     the AB is providing extended or conventional memory there won't be any
     conditions to compatibility.

     Tech Notes:
     Sigma Board uses B8000 to BFFFF for its Video RAM page and CC000-CDFFF
     for its Video BIOS ROM.  The 6K block used for the Video BIOS prevents
     use of C0000 block for AB's expanded memory page frame.  This means you
     MUST use D0000 for the AB page frame. Sigma 400 board I/O ports are
     2D0-2DF which do not conflict w/AB I/O ports.

     Field report that Sigma 400 BIOS Version 2.50H is incompatible with AB
     AT in the Compaq Deskpro 286.  Sigma reports this version works with
     the AB in the IBM AT.

 SIGMA COLOR 400 - BIOS VER & POWER CONSUMPTION

     The Sigma Color 400 with Bios version 2.52 (and possibly others) uses a
     'significant' amount of power according to tech support a Sigma. Watch
     for power supply overload problems with AB, or IB along with Sigma
     Color 400.

 IBM ADVANCED DIAGNOSTICS & SIGMA COLOR 400 BOARD

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

 SIGMA COLOR 400 & INSTALL, SETBOARD, TESTAB

     INSTALL, SETBOARD, and TESTAB cause a blank screen soon after loading
     if a Sigma 400 is present in the system.  EMM works fine with the Sigma
     400.

     SOLUTIONS:
     SETBOARD; there isn't one. The display will go away although the
     program is still active.  It is not practical to walk through SETBOARD
     without seeing where the display is, since SETBOARD is smart enough to
     choose it's current selections from the way the board is currently
     configured.

     INSTALL; it would be necessary to manually install the Intel software
     without the use of the INSTALL program, or use a different video
     adapter.

     TESTAB; Sigma 400 will cause a blank screen after asking operator to
     choose either 1 - for a PC system, or 2 - for an AT system.  It then
     (invisibly) diplays the switch settings for the AB with the LOWEST I/O
     port address, and asks a question.

       For a PC system:  "Do you want to continue? (Y or N)"
       For an AT system: "Is there a piggy attached? (Y or N)"

     If the operator chooses a response to the above question, the program
     will continue and the screens will become visible again.  The remainder
     of the test program should run correctly.

     If the program fails to continue, then it is possible that the system
     is not totally IBM compatible, and the invisible screen contained the
     error message, "Your system is not totally IBM compatible."

 SIGMA LASERVIEW

     *FIELD REPORTS* of compatibility with Above Boards, though there might
     not be enough reserved memory space available for expanded memory to
     load. Extended memory has no compatibility issues with this card.

     The Sigma Laserview board uses memory at D0000.  Set the AB page frame
     at C0000 in an AT or E0000 in a PC.

     If the C0000 & D0000 addresses are unavailable (due to network cards,
     EGA/VGAs, or other boards in their system), have them call Sigma
     Designs tech support.  They have a special driver set that MAY help
     some users with conflicts.  (It probably will NOT help with EGA/VGA
     problems.)

     Can also be set for address A0000, but some software (e.g. Publisher's
     Paintbrush and PC PaintBrush) expects the D0000 address and will not
     work unless the EXPL=CC00 option is used on the EMM line in Config.sys
     (AB Plus or Classic Bus EMM 4.0 Rev C only!).  The screen goes blank on
     invocation if EMM is using anything in the D000 segment.  (CUSTOMER
     REPORT)

     Some versions also use I/O port 248 and will show up as an occupied AB
     I/O port in SETBOARD.  This version of the Laserview is not compatible
     with INSTALL. (CUSTOMER REPORT) Sigma Designs Technical Support:  ph:
     15-770-0100.

 SOTA VGA

     *FIELD REPORTS* of compatibility with Above Boards, although there are
     some issues to be aware of when setting up the Above Board to provide
     expanded memory. Extended memory has no compatibility issues with this
     card.

     The Sota VGA adapter is a 16-bit VGA board.  When trying to install
     Expanded memory into a system that had this board, Install gave the
     message, "There is no Expanded memory to manage."  The Sota manual
     explains there is a PAL located in socket location U-29 on the SOTA
     board that can be removed to put the SOTA board in 8-bit mode.  This
     will allow the two boards to work together.

 STB

 STB CHAUFFEUR

     This is an IBM Color Graphics Adapter (CGA) compatible video adapter.
     We have one unconfirmed field report in July of 1986 of a Parity Check
     2 with an Above providing expanded memory with this video card
     installed.

 STB VGA EM16

     *FIELD REPORTS* of compatibility with Above Boards, although there is
     an issue to be aware of when setting up the Above Board to provide
     expanded memory.

     Since this 16bit VGA card doesn't do a true 16bit reserved memory
     access (it fluctuates between 8bit and 16bit reserved memory accesses),
     the VGA card needs to be set to an 8bit mode in order to work with our
     Expanded Memory Manager. If it did a true 16bit access we could add the
     16BIT=03 parameter to the EMM.SYS device driver line to get this
     working, but this parameter will lock up the system the first time this
     VGA card does an 8bit access of reserved memory.

     This 16-bit VGA board runs in 16-bit or 8-bit mode by switching jumper
     J-3. Jumper settings are on page 21 in the STB manual.

     STB supplies RAPIDBIO.COM program that caches the VGA ROM into
     conventional memory. Put this as the first command in the AUTOEXEC.BAT
     file to alleviate performance degradation in 8-bit mode.

 SYSDYNE VGA 800

     *FIELD REPORTS* of compatibility with Above Boards but must turn off
     the Autoswitching functions of the Sysdyne VGA in order to get expanded
     memory to work (switch #5 on the back of the Sysdyne VGA card).

 VGA MEMORY USAGE

     Some general info:

     VGA's in general use ALL of A0000 to BFFFF for video data. These guys
     tend to be in EGA mode most of the time because software has to be
     rewritten to use REAL VGA capabilities. There are more and more REAL
     VGA applications being written daily.

     VGA mode itself has several modes i.e. 640 x 480 w/sixteen colors, 320
     x 200 w/256 colors (WOW the shading) and some others.

     The VGA board has TWO eproms located at C0000 to C7FFF which in effect
     is an extention of EGA (EGA used C0000 to C3FFF) so we can forget about
     the lower half of the C0000 area for use when providing expanded (LIM
     EMS) memory.

     Most VGA boards occupies (not necessarily always uses) the area from
     A0000 to C7FFF (160k!).

     IBM 's VGA in the PS/2 machines don't occupy the C0000 to C7FFF area
     because the BIOS supports it directly.



End of file                 Intel FaxBack # 1442          August 7,1992
