Solution:

Get DOS Date Software interrupt AH = 0x2A CX:Year DH:Month DL:Day AL: 0 - Sunday 1 - Monday 2 - Tuesday 3 - Wednesday 4 - Thursday 5 - Friday 6 - Saturday Set DOS Date Software interrupt AH = 0x2B Success: AL - 0 Fail : AL - FF Get DOS Time Software interrupt AH = 0x2C CH for Hour : 0-23 CL for Minute : 0-59 DH for Second : 0-59 DL for 1/100 second : 0-00 Set DOS Time Software interrupt AH = 0x2D Success: AL=0 Fail: AL=FF For BIOS Time Software Interrupt 0x1A, 0x04/0x02 Get RTC Date (CMOS) To read 128 Bytes CMOS data (for AWARD BIOS), you must use direct port address. Index Port 70 Data Port 71 For Year (09H) C:>DEBUG -o 70 09 -i 71 98 For Centry (32H) C:>DEBUG -o 70 32 -i 71 19 Outportb (0x70,0) seconds = inportb (0x71) outportb (0x70,2) minutes = inportb (0x71)