DATETEST www.merlyn.demon.co.uk >= 1999-02-13
Borland Pascal : GetDate, GetTime =>   1999-02-13 17:50:16
Read  RTC with BIOS Int 1A/04, 1A/02   1999-02-13 17:50:16
   Dos values are saved in SaveDos ;

Decrement Day and Hour
Write RTC with BIOS Int 1A/05, 1A/03
Read  RTC with BIOS Int 1A/04, 1A/02   1999-02-12 16:50:16
Read  RTC by direct port access :      1999-02-12 16:50:16
Borland Pascal : GetDate, GetTime =>   1999-02-13 17:50:16
The paragraph ending here should show
  that now the RTC is 25 hours slow, but DOS is correct.

Now WriteDos(SaveDos) ;
Read  RTC with BIOS Int 1A/04, 1A/02   1999-02-13 17:50:16
Read  RTC by direct port access :      1999-02-13 17:50:16
Borland Pascal : GetDate, GetTime =>   1999-02-13 17:50:16
The paragraph ending here should show
  that correcting DOS has corrected the RTC as well.
<cr>