SCO XENIX 2.2.3 on AT with TVGA display adapter, help request ...

[Francis Demierre]

This article describes a configuration problem of the SCO 2.2.3 on a PC
AT clone equipped with a TRIDENT VGA display adapter and requests for help.
If you are not interested, PRESS 'n' or 'q' now ..... (Last chance ;-) )


Hello NetLand,

Here in ASCOM Hasler, I have installed the SCO XENIX version 2.2.3 on a PC
AT clone equipped with a TRIDENT VGA card (Trident Microsystems, Inc.).
(Exact config at the end of article)

When I tried to boot with the 2.2.1 BOOT diskette, the following was happening:
  1) Usual RAM test (Cold boot)
  2) The TVGA Card video BIOS banner is displayed
  3) Systems starts booting installation diskette
  4) Request for the Filesystem Diskette is displayed
  5) A few seconds later the system reboots itself and loop to 2) above.

When I tried to boot with the 2.2.3 BOOT diskette, the systems boots ok but
garbage is printed onto the screen. The text is just not rendered correctly
but the system works; i.e. the panel for system language selection is on the
screen.

Finally, I installed SCO XENIX 2.2.3 from a terminal connected to COM1: in
the hope I could solve the console problem later. Unfortunately, I could 
not solve it !

The system comes up ok but the display still shows garbage character although
the system works ok when I type commands (blindly).

The card does not include any switch to lock it into EGA mode so I tried several
C programs to try switching the card (Basically getting the current mode of the
tty with ioctl() CONS_CURRENT cmd, for which the driver returns '4' (EGA) and
then opening /dev/ega to get the current display mode which happen to be '22'
(EGA 25*80 color) or to try programing it in different modes).
Unfortunately, none of my trials did succeed  :-(

I also tried the stty(1) command with all sorts of combinations but still no
success ...

I also tried playing with the DIP switches, especially switch 5 (Fast/Slow
address decode) and switch 6 (8 or 16 bit data path) + Jumper J2 (Automatic
Bus size detection / 8 bit BIOS interface). NO SUCCESS :-(( 

I did not mention but, of course, everything is OK under DOS and all emulation
modes can be used without problems.

Did anybody succeed installing SCO XENIX 2.2.3 on an IBM AT (or clone) which
has a VGA card as the primary display adapter ? 

Anything I missed, any trick, patch, workaround ????

Please, preferably E-mail your answers directly to me unless you think
the subject is of general interest.

Thanks in advance, Francis

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Configuration:

   - Hyundai PC AT with
       640 Kbytes on mother board
       512 Kbytes extension memory
       2 Serial/Parallel Adapters ( Mouse on COM1: )
       1 HD+Floppy(A:) Adapter

   - TVGA card with 256K On-board RAM (16 bits Bus version) installed
     in a 16 Bits Bus slot.
     Switches: 1-4 : Monitor type
                 5 : Fast/Slow address decode = Fast
                 6 : 16 / 8 Bits data path    = 16 bits

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Francis Demierre       UUCP: ...!mcsun!chx400!hslrswi!francis
                       Internet: francis at hasler.ascom.ch
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