49.7 days

 

Do you know about this???
 
Will Windows work continuously for more than 49.7 days?
 
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
(232)-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.
 
Please check this knowledge base article 216641:
http://support.microsoft.com/kb/216641/EN-US/