Windows RTC Clock and System Timer

[Pandiani]

Hello, in Hardware/Device Manager (win XP) I found under system devices (among others):
1. System CMOS/Real Time Clock IRQ 08
2. System Timer IRQ 00

Can someone please explain what is purpose of RTC and System Timer. I suppose to count time but I'm not sure. Also what is difference between RTC and System Timer?
Since System Timer has lower IRQ address I assume it is more important. Is it true that system timer every 50 milliseconds (or so) generate interrupt that enable keyboard stroke, mouse clicks and other event to be noticed by Windows?
Please, if someone can clearfy this, I would greatly appreciate it.
Thanks

[ScreechPowers]

In writing games, it is important sometimes to make use of system timers. When you shoot a rocket, it moves at xx speed, or yy pixels in zz time. If it is off, it might appear to 'jump' forward or hold back. Actually, any real time application needs to make use of the timers. Though they could, in theory, check the clock, you would have to format that data to find out how much time has passed, or anything not dependant on the time of day. :wave: is a perfect example. Once loaded onto your computer, this file plays. This many frames in this much time is designated by whoever made the thing. Standard video is 24 frames per second, so to play it back, the computer must time a second. It would slow down the system immensly if these programs had to use only the time of day for this, as math with that can not be done in base 10 or 2. So basically, they are for other programs to use, and I talk too much.