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The CPU Utilization of a computer is 100%.

Is it possible to execute a new application under the above condition?

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migrated from stackoverflow.com May 4 '11 at 21:50

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It's impossible to say. If the operating system has some sort of scheduling, then yes, because sooner or later the process which controls the starting of new application will get its time share and be able to start it. If there's no OS or a real time OS, then the answer may be no. –  AndrejaKo May 4 '11 at 21:55
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If there is no OS, the "execute a new application" has no meaning. –  karatedog May 4 '11 at 21:57

2 Answers 2

On operating systems with preemptive multitasking it is possible. The scheduler will interrupt the offending process so that other processes can get some time to run as well, but the offending process will still tend to hog the cpu and make the system feel very slow.

On OSes with cooperative multitasking it is only possible if the process which is using 100% of the CPU yields processor control.

See: http://en.wikipedia.org/wiki/Computer_multitasking

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A hardware interrupt will always, well, "interrupt" the CPU, no matter what else the CPU is doing. It would be possible for an operating system to be designed to respond to a hardware interrupt and launch an application even all CPU is being utilized. The mechanism that most operating system schedulers use to "enforce" preemptive multitasking is hardware based. Even under co-op multitasking systems an interrupt handler can change things, but this must part of the design beforehand. –  ultrasawblade May 10 '11 at 20:25
    
Isn't that how preemption already does things? The CPU sends an interrupt at a regular interval which allows the scheduler to run and decide what gets to run next? –  Andrew Lambert May 10 '11 at 20:29

Yes.

Assuming a "modern" operating system the available resources will be shared between processes, therefore if you have 1 application (which is let's say 1 process) that received that 100%, by starting the 2nd application the OS will split that 100% into 50%-50%.

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