even windows needs some rest…….



how long can windows run without being shut down……???

read on…

Here is a bit of information, which may surprise you all. Windows crashes
automatically if you don’t switch off the machine for 49.7 Days. Microsoft accepts
this. Do you know why?

In Windows the Virtual Machine Manager (here after referred as VMM) is responsible
for creation, execution, monitoring and termination of virtual machines. This VMM,
which is a 32 bit, protected mode operating system entity, provides a number of
system services at chip level. One of these services is “Get_System_ Time”. This
particular service loads the EAX register with the time in milliseconds since
Windows started on that machine. This service is accurate to 1 ms. EAX is a 32 bit
register in Intel 386 Processor onwards.

So the maximum number of milliseconds it can hold is
(2^32)-1 = 4294967295 milliseconds = 4294967.295 seconds = 71582.79 minutes = 1193
hours = 49.7 days.
So after 49.7 days the EAX resets to zero. Most of the Drivers use this Time Service
to keep track of the Timeout of various services they provide. So after 49.7 days
the drivers cannot use the Get_System_Time function of VMM and they crash taking the
OS along with.


3 thoughts on “even windows needs some rest…….”

  1. will the processor speed play and important role in counting??
    ie if processor is of higher speed then since at each clock pulse register will
    increment thus reducing time for counting (ffffffff) (32 bit)??

    by da way information provided is g8!!

  2. @ omkar

    the processor’s speed doesn’t hv much to do wid the time..’cause the processor speed determines the no. of machine cycles a system makes in a second, so the timke counter will increase only after one milisecond, watever d processor speed may be…
    so d processor speed doesn’t really hv anything to do in this context…

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