Category : Miscellaneous Language Source Code
Archive   : TICKTOCK.ZIP
Filename : TICKTOCK.DOC
The TICKTOCK programs demonstrate how to obtain accurate timing
information from the IBM PC/XT/AT family of computers. The next
few paragraphs should give you a basic idea of how the time is
stored in these computer systems.
In the PC family, an internal clock runs at 1.193180 Mhz. This
clock is divided by 65536 to give 18.206482 clock pulses per
second (.0549255 seconds per clock pulse). Therefore, the clock
'ticks' every .0549255 seconds.
Two addresses in low memory are used to keep track of the tick
count. They are both 1 word (two bytes) in length. The first is at
address 0000:046C. It is incremented 18.2 times a second. When it
overflows, it is reset to 0 and another word at address 0000:046E
is incremented.
It should be noted that the word at address 0000:046E is also the
current hour, in 24 hour format. The address at 0000:046C when
divided by 18.2, is the current time past the hour, in seconds.
Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!
This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/