Farseerfc的小窩 - microsoft

“…if we do this work … ” --Bill Gates

2011-03-14T20:34:00+09:00

導入自 renren

From: Bill Gates

’-- Sent: Sunday, January 24, 1999 8:41 AM

Jeff Westorinon; Ben Fathi ;

TO: Carl Stork (Exchange); Nathan Myhrvofd; Eric Rudder

Subject: ACPI extensions

One thing I find myself wondering about is whether we shouldn’t try and make the "ACPI" extensions somehow Windows specific.

It seems unfortunate if we do this work and get our partners to do the work and the result is that Linux works great without having to do the work.

Maybe there is no way to avoid this problem but it does bother me.

Maybe we could define the APIs so that they work well with NT and not the others even if they are open.

Or maybe we could patent something relaled to this.

From:

http://antitrust.slated.org/www.iowaconsumercase.org/011607/3000/PX03020.pdf

如果這就是我至今在Xen4.0上得不到ACPI 3.0的完善支持的原因，那麼我詛咒Bill Gates！

寫程序讓CPU佔用率保持正弦函數

2008-06-02T23:27:00+09:00

導入自 renren

據說是一道微軟的面試題。如題，寫程序，讓Windows的任務管理器中的性能監視器呈現正弦曲線。

潛心鑽研良久，得代碼：（java）

public class sincpu {
    private static final int cycle=1024,tick = 256;
    public static void main (String[] args) throws InterruptedException {
        for(int i = 0;;i++){
            work(calcNextSleep(i % cycle));
            sleep(tick - calcNextSleep(i % cycle));
        }
    }

    private static long calcNextSleep(long i){
        return (int)(Math.sin((double)i * 2 * Math.PI / cycle) * tick + tick) / 2;
    }

    private static void sleep (long sleepTime) throws InterruptedException
    {
        if(sleepTime < 2)
            Thread.yield();
        else
            Thread.sleep(sleepTime);
    }

    private static void work (long period) {
        long start = System.currentTimeMillis();
        for(;;){
            Math.sin(1);
            if(System.currentTimeMillis() - start >= period)
                break;
        }
    }
}

多核CPU上測試時要注意關掉一個CPU：