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  Interrupt 11H (decimal 17) reports what equipment is installed in the
  computer. This report contains the same information stored at low-memory
  location 0040:0010H. (See Chapter 3, page 55.) The report is coded as
  shown in Figure 12-17, in the bits of a 16-bit word, which is placed in
  register AX. See interrupt 12H for a related service.

  The equipment information is gathered on an as-accurate-as-possible basis
  and may not be exactly correct. Different methods are used for acquiring
  the information in the various models.

  The equipment list is determined only once at power-up time and is then
  left in memory. This means that you can change the equipment list under
  software control. For example, you could take some equipment off line so
  that it is not used. However, modifying the equipment list is risky
  business--don't bet on its success. See interrupt 19H for comments on how
  to modify the equipment list and get reliable results.


                           Bit
  15 14 13 12 11 10  9  8   7  6  5  4  3  2  1  0        Meaning
  ----------------------------------------------------------------------------------------------
   X  X  .  .  .  .  .  .   .  .  .  .  .  .  .  .        Number of printers installed
   .  .  X  .  .  .  .  .   .  .  .  .  .  .  .  .        (Reserved)
   .  .  .  X  .  .  .  .   .  .  .  .  .  .  .  .        Game adapter: 1 = installed
   .  .  .  .  X  X  X  .   .  .  .  .  .  .  .  .        Number of RSS-232 serial ports
   .  .  .  .  .  .  .  X   .  .  .  .  .  .  .  .        (Not used)
   .  .  .  .  .  .  .  .   X  X  .  .  .  .  .  .        Number of diskette drives -1
   .  .  .  .  .  .  .  .   .  .  X  X  .  .  .  .        Initial video mode: 11 = monochrome;
                                                          10 = 80-column color;
                                                          01 = 40-column color
   .  .  .  .  .  .  .  .   .  .  .  .  X  X  .  .        PC with 64 KB motherboard: Amount of
                                                          system board RAM (11 = 64 KB;
                                                          10 = 48 KB; 01 = 32 KB; 00 = 16 KB
                                                          PC/AT: (Not used)
                                                          PS/2s: Bit 3 = (unused); bit 2: 1 =
                                                          pointing device installed
   .  .  .  .  .  .  .  .   .  .  .  .  .  .  X  .        1 if math co-processor installed
   .  .  .  .  .  .  .  .   .  .  .  .  .  .  .  X        1 if any diskette drives exist (if so,
                                                          see bits 7 and 6)
  ----------------------------------------------------------------------------------------------


  Figure 12-17.  The bit coding for the equipment list reported in register
  AX and invoked by interrupt 11H (decimal 17).

  The format of the equipment list was defined for the original IBM PC. As a
  result, some parts of the list vary, depending on the PC model. For
  example, bits 2 and 3 originally indicated the amount of RAM installed on
  the motherboard. (Yes, in those days you could indeed have purchased a PC
  with as little as 16 KB of RAM.) In PS/2s, these bits have a different
  significance. (See Figure 12-17.)