See also:
 Int/11

  Bits	  Description and
	   Values
  ------- ------------------------------------------------------------
  0	  1 if floppy drive present (see bits 6&7)  0 if not
  1	  1 if 80x87 installed	(not valid in PCjr)
  2&3	  system board RAM   (not used on AT or PS/2)
	  00 - 16k   01 - 32k	10 - 48k    11 - 64k
  4&5	  initial video mode
	  00 - no adapter	 01 - 40 column color  (PCjr default)
	  10 - 80 column color	 11 - MDA
  6&7	  number of diskette drives minus one. (drive count is bit value + 1)
  8	  0	 DMA present
	  1	 DMA not present (PCjr, Tandy 1400, Sanyo 55x)
  9&A&B   number of RS232 serial ports
  C	  number of game adapter (joystick) installed
  D	  number of serial printers installed (PCjr only)
  E&F	  number of parallel printers installed

  note 1) The IBM PC and AT store the settings of the system board switches or
	  BIOS/CMOSRAM setup information (as obtained by the BIOS in the
	  Power-On Self Test (POST)) at addresses 40:10h and 40:13h.