DTK BIOS Post Codes
 01   Testing the CPU 
 03   Initialize the 8259 interrupt controller 
 05   Initialize the video board - MCA & CGA 
 0D   Initialize the 8237 DMA controller 
 0E   Initialize the DMA 74612 page registers 
 12   Test the 8042 keyboard controller 
 16   Test the DMA 7237 controller and 8254 programmable interrupt timer 
 22   Testing DRAM refresh circuitry 
 25   Base 64KB memory test 
 30   Set up system stack 
 33   Read-system configuration through 8042 keyboard controller 
 37   Test keyboard clock and data line 
 40   Determine video type 
 44   Locate and test, if present, MDA and CGA video 
 48   Initialize video 80 x 25 mode 
 4D   Display DTK BIOS copyright message 
 4F   Check serial and parallel ports 
 50   Check floppy disk controller 
 55   Check shadow RAM 
 58   Display total memoryand switch to real mode 
 5A   Successful switch back to real mode 
 60   Check hard disk drive controller 
 62   Initialize floppy drive 
 65   Initialize hard drive 
 67   Initialize the floppy disk drive and the hard disk drive 
 6A   Disable gate A20 and test math coprocessor 
 70   Set system date and time RTC-146918 
 77   Call interrupt 19 boot loader