[AccessD] Classes and Events - EVENTS NOT REQUIRED

On 11 Feb 2009 at 0:22, jwcolby wrote:

> Stuart,
> 
> My understanding of the 10 ms deal is simply that each time slice allocated by the OS (pre-emptive 
> multitasker) is 10 ms.  The tick count is still 1 ms regardless of the time slice length, even for 
> XP / 2K.  Again my understanding is that the tick count comes off the system clock.  I will admit it 
> has been a long time since I looked at that stuff however.
> 

 It's all about how often a clock interrupt is generated:

"Microsoft Windows XP uses a periodic clock interrupt to keep track of time, trigger timer 
objects, and decrement thread quantum. When Windows XP boots, the typical default clock 
interrupt period is 10 milliseconds, although a period of 15 milliseconds is used on some 
systems. That means that every 10 milliseconds, the operating system receives an interrupt 
from the system timer hardware. "

This is from http://www.microsoft.com/whdc/system/sysinternals/mm-timer.mspx
which is all about the requirements for a new timer in chipsets for future Windows versions.

It is an interesting read. It has a very good description of the problems inherent in the 
current hardware clocks and why there is a need for low-overhead true millisecond timers.

-- 
Stuart