🚀 go-pugleaf

jy@wasp.eng.ufl.edu (Jim Yousse) writes:

>Does anyone know about the Midnight Bug in DOS, where the clock does not
>register a date change when passing midnight?  We have a user here who
>leaves her machine on continuously, and every now and then it will lose
>a day.  We're pretty sure this is the midnight bug in action.  We've heard
>of fixes for this, but don't know where to get one.  Any suggestions?

Well, unless you have an *old* version of DOs, it works like this:

At midnight, the TimerCount (in the BIOS work area at 0040:????) is
reset to 0. And another memory location in that area is *set* to 1.
(Not incremented, *set*).

The next time anything asks DOS for the date or time, DOS sees the "flag"
is set, clears it, and increments the date by one. 

So you only lose a day if nothing asks DOS for the Date or time for
*two* days. 

The solution is to install *something* that keeps checking the time,
say a menu program with a clock display in the corner. Or even a TSR
that displays the time on screen somewhere.

Last I heard, Microsoft had no intention of fixing this.
-- 
Leonard Erickson			leonard@qiclab.uucp
personal:	CIS: [70465,203]	70465.203@compuserve.com
business:	CIS: [76376,1107]	76376.1107@compuserve.com