Z2K9 and E2K9

This New Year’s we witnessed 2 catastrophic tech failures:  Zune and Evite.  On New Year’s Eve, Zune 30s all over the world froze.  Microsoft said it was due to “‘a bug in the internal clock driver,” and that affected Zunes would work the following day.  For evite, the site went down on one of the busiest party nights of the year around 6pm EST and did not come up until after the ball dropped.  I, along with possibly millions of others, could not access NYE party information which is only stored on the evite site.  This is particularly bad as evite has more competition than ever, and people are just looking for reasons to switch to something else more web 2.0-ish.

So, some industrious poster tracked down the Zune clock source code.  Here is the bad code, which is called whenever the Zune needs the current date:

year = ORIGINYEAR; /* = 1980 */

while (days > 365)
{
    if (IsLeapYear(year))
    {
        if (days > 366)
        {
            days -= 366;
            year += 1;
        }
    }
    else
    {
        days -= 365;
        year += 1;
    }
}

This method take an argument of “days”, which is the number of days since 1/1/1980.  If days=366 and isLeapYear() is true, then this loop does nothing and will loop forever.  These conditions always occur on the last day of a leap year (e.g 12/31/2008) !  The bottom-line is that when you write a loop, you need to be certain it will terminate.  Having a convoluted assortment of if-statements it not a good way to accomplish this.

So we know the Zune crash was caused by a date bug, but the evite error has not been explained.  I donned my investigative reporting hat, and sent an email to evite support asking what went wrong on NYE.  They replied with an email which clearly was anot written by a human, which lead me to believe that perhaps the outage was caused by a take-over of robots.  Anyway, I did not give up that easily and replied again this time with a concise: “What caused the outage?”  I haven’t heard back yet, but I’ll keep you posted!

Tags: , , , , , ,


%d bloggers like this: