Archive for September, 2009

explain the trick

Tuesday, September 8th, 2009

What happens when something looks too easy? Or the context is wrong?

This Labor Day weekend ( For the non-US people The “official” end of the summer in the U.S. first Monday in September – not May 1 ) me and my family went to the California State Fair.

There we saw Frank Oliver, a magician and his sidekick doing a bunch of tricks, fire swallowing, etc. My kids absolutely loved the show. One of the “tricks” was sword swallowing. Frank announces that his personal best was 19 inches and now he is going to attempt to do 22 inches for the “first time”. ( Having seen the show earlier in the day I knew that he had done it before — of course! ). Frank sits on the chair and his assistant makes a show of hammering the sword down.

Frank made it look so easy. Too easy.

Like everyone else in the audience, I was certain that there was a “trick” – the sword was rigged and it collapsed, or something. I discovered that there is no “trick” with sword swallowing. Frank was actually swallowing the sword and sword shallowing is quite dangerous:

Learning to ignore an involuntary process takes a tremendous amount of practice. In the case of sword swallowing, it generally involves deliberately activating the gag reflex over and over. The process can cause vomiting and considerable discomfort. It also dulls or removes a process intended to protect the person from harm. This is one of the many reasons why sword swallowing is dangerous.

The study involved the voluntary survey of 110 English-speaking sword swallowers. Forty-six of the 48 performers who responded consented to having their data used in the study. Thirty-three of the respondents included information about their medical histories. From most to least common, the side-effects they experienced from sword swallowing included:

* Throat pain, or sword throat
* Persistent lower chest pain, likely from injury to the esophagus or the diaphragm
* Internal bleeding
* Esophageal perforations, three of which required surgery
* Pleurisy, an inflammation of the lungs
* Pericarditis, an inflammation of the sac that covers and protects the heart

Furthermore,sword-swallowing-2

The Sword Swallowers Association International (SSAI) defines a sword swallower as a person who can swallow a 15-inch (38-centimeter) sword, which wouldn’t necessarily enter the stomach. The SSAI’s maximum recommended length for a swallowed sword is 24 inches (61 centimeters), which would put the tip of the sword well into the performer’s stomach [Source: swordswallow.com]

So 22 inches was near the extreme end of what was possible.

Something this dangerous and this involved deserves a better build up than being in the middle of an act and casually done. Frank should have explain how dangerous sword swallowing is, built up the suspense and drama. Instead sword swallowing was devalued simply because the lead-in was casual and it was treated like a joke.

Some times hard things should be made to look hard.

What about your company’s product? Is your company doing something hard and devaluing it because the difficulty of the problem is not being bragged about? Should the customers be aware of how hard the problem was — so they appreciate and value your solution more?

Posted in marketing, starting a company | No Comments »

Gmail and the Electrical Grid: Looks the same

Wednesday, September 2nd, 2009

GMail had a large-scale cascading failure yesterday:

At about 12:30 pm Pacific a few of the request routers became overloaded and in effect told the rest of the system “stop sending us traffic, we’re too slow!”. This transferred the load onto the remaining request routers, causing a few more of them to also become overloaded, and within minutes nearly all of the request routers were overloaded.

This cascading failure sounds exactly like that other universal network we all share: The electrical grid.

Large blackouts are cascading failures compounded by the failure of the “fuses” meant to isolate still functioning parts of the grid from the failed part.

Sounds a lot like what happened to gmail.

Interestingly the smart people at Google have recognized exactly that:

we have concluded that request routers don’t have sufficient failure isolation (i.e. if there’s a problem in one datacenter, it shouldn’t affect servers in another datacenter) and do not degrade gracefully (e.g. if many request routers are overloaded simultaneously, they all should just get slower instead of refusing to accept traffic and shifting their load).

Sounds like a good start. But what happens if a datacenter catestrofically fails. The routers stop accepting requests because they are gone ( or can’t respond ). Prepare for the next GMail failure.

As wikipedia notes:

Modern power systems are designed to be resistant to this sort of cascading failure, but it may be unavoidable (see below). Moreover, since there is no short-term economic benefit to preventing rare large-scale failures, some observers have expressed concern that there is a tendency to erode the resilience of the network over time, which is only corrected after a major failure occurs. It has been claimed that reducing the likelihood of small outages only increases the likelihood of larger ones. In that case, the short-term economic benefit of keeping the individual customer happy increases the likelihood of large-scale blackouts.

Posted in technical | 3 Comments »