Deaf Smith (pronounced Deef Smith) was a famous character from Texas history - served as a scout for Sam Houston. Seemed appropriate for me - I live in Texas, I'm about half deaf, and my middle name is Smith.
The avatar - a picture of one of my slide rules. For those who are thinking "What the hell is a slide rule?", there was a time, not so long ago, when there were no personal computers, no cell phones, no iPods or iPads, no interwebz, not even pocket calculators. If you needed to make some calculations involving more than addition and subtraction, you had a choice: pencil and paper, a table of logarithms, or a slide rule. In fact, the slide rule was as much a symbol of the engineer as a stethoscope is a symbol of a doctor. I'm old enough to remember those days - a slide rule was my constant companion in college and my first few years on the job as an engineer. When I bought my first electronic calculator in 1973, I tossed my slide rule in a drawer, not to see the light of day until I got interested in slide rules again a few years ago. I realized what an amazingly clever instrument the slide rule is and began collecting them. Anyway, the avatar pic is a low resolution version of a pic I posted on a slide rule forum to show how I modified the cursor to change the folded scales from being folded at pi to being folded at sqrt(10), which has some advantages. Yeah, I know, that's TMI.
I do use a slide rule in brewing - once I know my preboil volume and gravity, I can see at a glance what the gravity will be for a given post boil volume, or conversely, what volume I will have for a given OG. For this job, slide rule > digital calculator.