Monday, May 3, 2010

How much do you need to know?

This question occurred to me as I was plowing through the “FireWire™ Reference Tutorial” published by the 1394 Trade Association. (Before you click on the link, know that it’s a 2.3MB pdf document.)

The Tutorial is probably the definitive explanation of what FireWire™ is and how to use it, but at 78 pages it may be just a tad too long for those of us with work to do. So how much do we, as users of machine vision, need to know about the various camera connection interfaces? Is it enough to simply understand the frame rate limitations and the need for an appropriate interface card, or will we build a better system if we grasp the intricacies of 1394 protocol layering?

My general policy on education is that it is a “good thing” and that more is always better, but perhaps there has to be a limit. The introduction to the Tutorial says it is aimed at engineers “who desire to acquire a technical background on IEEE1394 that covers more the surface, marketing-grade material that appears in articles found in tech magazines and web site.” That almost sells it to me, but then 78 pages to wade through? Is there an executive summary I could read?

Here’s the problem: FireWire™, in common with the other interfaces such as GigE and CameraLink, is not simple. I’ve seen several engineers give up with FireWire and switch to the more expensive CameraLink because they couldn’t get reliable performance from their 1394-based system. Obviously, this waste of time and materials is expensive, but could it have been avoided by reading this heavyweight document?

We will never know, but on balance I come down on the side of learning more than you need. After all, you don’t know what you don’t know.

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