I've had the same thing happen to me recently as well. I was on a
Continental flight from Houston to Calgary (airplane was a Boeing
737-700, btw) last month, when the pilot announced that she had to do a
"hard reboot" by turning off all of the electrical power to the plane to
try to fix a problem with the on-board computer system. The power to the
plane went off and back on again after a short delay, and after a minute
or two, the pilot announced that the system was now working to her
satisfaction....
That in both cases, the pilots used the same term "hard reboot" and the
same procedure to correct the problem tells me that this must be the
standard, approved method in the airline industry for addressing such
issues. It certainly didn't give me the warm fuzzes.....:-)
I don't know what the computer problem was (other than it was serious
enough to prevent us from taking off had the pilot not been able to
rectify it), nor what hardware processor or what software was involved.
The plane itself was fairly new, being less than 5 years old.
DJ
Phil Smith III wrote:
For those of you who don't read RISKS (and you all should! www.risks.org), I thought the
following would be amusing/interesting. When he started writing about being told not to
touch any buttons during the restart, I was thinking of DDR, with its "first
interrupt gets the console" approach...but no, it's Linux!
...phsiii
-----Original Message-----
Date: Tue, 28 Nov 2006 13:29:42 -0600
From: "Douglas W. Jones" <[EMAIL PROTECTED]>
Subject: Rebooting airplanes
In the last few weeks, I've done quite a bit of flying, and twice, now, I've
been on planes where they had to reboot.
The first trip where this happened, as we were scheduled to leave the gate,
there was a delay, and then the pilot said over the intercom: "We're having
trouble with some of the cockpit instruments, so I'm going to force a hard
reboot by switching off all the power for a bit." The lights and all other
power on the plane then went off, and after a fifteen second pause, on
again. A minute later, the pilot said: "That seems to have fixed the
problem," and we were off.
I wasn't impressed. As far as I am concerned, this is clear evidence of a
genuine design error somewhere in the system.
The second problem happened on Sunday, on a flight back from Amsterdam. On
that flight, they had serious problems with the in-flight video on demand
system. They tried a "soft reboot" of some kind, and it didn't work, so
they then tried two "hard reboots," their term, and after the second try, it
worked fine. Their instructions were "until the system comes all the way
up, please don't touch any buttons." That alone suggests poor design. The
system ought to come up with interrupts disabled on any devices that it's
not ready to listen to, after all.
The reboot process took close to half an hour, and watching the displays in
the seat backs that were visible from my seat, I could see that they were
being rebooted in sequence, about one per second. Furthermore, as each
in-seat display was rebooted, it showed the Linux penguin and then a Linux
boot script, revealing that each seat-back display was a little Linux
system, suggesting that they were all networked to a video server for the
plane.
Again, the need for these global reboots is strong evidence that the systems
were not well designed,
I wonder if both of these stories illustrate problems with the kinds of
graduates we are turning out these days. CS programs across the country are
emphasizing high-level courses in web programming, but fewer and fewer
students know anything about the fundamentals of parallel programming that
underly things. So, in constructing the kinds of distributed applications
that show up in contexts like streaming video and cockpit instrumentation,
they are working without the theoretical underpinnings needed to understand
the problems they encounter.
