wales@ucla-cs.UUCP (03/05/87)
I found that the date *does* advance at midnight on a Leading Edge Model D with MS-DOS 3.10. Further, the date advances at midnight on my system when I boot it with an MS-DOS 3.10 from Leading Edge (whereas it doesn't advance when I run the MS-DOS 3.2 that came with my system). Hence, the problem wouldn't appear to be in my system's BIOS. I'm forced to the conclusion that either MS-DOS 3.10 (does this mean the same thing as "MS-DOS 3.1"?) doesn't have the "midnight" bug and MS-DOS 3.2 does -- or that Leading Edge fixed the "midnight" bug in the version of MS-DOS 3.10 that they distribute. The Phoenix BIOS in the Leading Edge Model D *increments* the "midnight" flag at 00470H (unlike the Award BIOS in my PC, which simply sets this flag to 1). However, when I wrote a larger value into 00470H via DEBUG, the Leading Edge MS-DOS 3.10 still only advanced the date by one day. Hence -- as someone pointed out -- an idle Leading Edge system that didn't do at least *one* "get the date" operation per day could lose track of the date. I haven't tried "stress-testing" the Leading Edge to see if it misses a day if there's lots of disk activity going on at the moment the clock flips over. -- Rich Wales // UCLA Computer Science Department // +1 213-825-5683 3531 Boelter Hall // Los Angeles, California 90024-1600 // USA wales@LOCUS.UCLA.EDU ...!(ucbvax,sdcrdcf,ihnp4)!ucla-cs!wales "Sir, there is a multilegged creature crawling on your shoulder."