PR> Can somebody give me a short example in asm, c, or c++ 
 PR> of a direct screen write? just the letter 'A' at 
 PR> b800:0000 would be lovely... please don't mock me with

User programs (ie: everything but device drivers) can not access a specific
physical memory address.  You'll never be able to write directly to
b000/b800.

The Vio api provides a function (VioGetPhysBuf) that manufactures a
selector (a "protected mode segment" register) that you can use
instead. Your program,  of course,  can only use this selector in full
screen (locked) sessions;   because I this I STONGLY discourage you from
using it.

Use the Logical Video Buffer instread (VioGetBuf/VioShowBuf),  or better
yet,  forget about poking character/attribute pairs into a buffer and use
functions like VioWrtCharStr() instead.

For docs in Vio,  look for PRCP.INF (prcp.zip) on this and other fine os/2 bbs's.

Here's an LVB sample I wrote for someone else:

 // compiled with ibm cset++ v2:
 // icc /W2 /Wall /O /Oi /Rn /Sse /G4  vio.c
 #define INCL_NOPMAPI
 #define INCL_VIO
 #include 
 #include 
 #include 

 int main(void)
 {
     ULONG ulLVB = 0;
     PVOID16 p16;
     USHORT usLen = 0;
     char *pb;

     VioScrollUp(0, 0, 0xffff, 0xffff, 0xffff, " \x7", 0);  // cls

     VioGetBuf(&ulLVB, &usLen, 0);
     /* VioGetBuf,  being a 16bit OS/2 1.x function,  returns a seg:off
      * pointer.  Force 'p16' to point to it,  then get the compiler
      * to thunk it to a 0:32 pointer.
      */
     p16 = (PVOID16)ulLVB;       // no thunk.
     pb = (char *)p16;           // thunk.

     VioSetCurPos(0, 0, 0);      // so printf is at top
     printf("lvb16=%p,  lvb32 = %p,  len = %d\n", p16, pb, usLen);

     pb += 160;      // skip the first line,  where our printf() is.
     memset(pb, 'A', (size_t)usLen - 160);
     VioShowBuf(160, (USHORT)(usLen - 160), 0);
     return 0;
 }
  /*
   * Note:  It is almost always better not to use
   * VioGetBuf/VioGetPhysBuf. Use VioWrt....() instead.  The trick is not
   * to call VioWrt...() for each character;  buffer each line (or more).
   */


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