The Joy of Slide Rules

Unexpectedly, the sliderule bug has bitten me fast and hard...

Non-logarithmic slide rules (pdf)
The scale on a slide rule doesn't have to be logarithmic. It could be a triangular number scale.

Mystery of Log Log Scales
How to use Log Log scales to raise numbers to non-integral powers, like 3.14^2.71

Slide Rule Simulator
A windows EXE app that lets you construct and test a virtual slide rule. The help file is good - it explains how to actually do the various calculations on the rule. UPDATE: My own attempts at a slide rule emulator can be found here, here and here.

Graphical List of Scales
An image showing every possible scale you might encounter on a slide rule.

The SUV's of Slide Rules
The Pickett N4 probably holds the record for being the slide rule with the most scales (34), but the Faber Castell 2/84N "could be considered the culmination of the development of the slide rule by one of Europe's leading manufacturers." Better pics of the N4 here.

Is perl6 Parsable?

I'm not sure if this post to perl.perl6.language is meant to be a joke, if it's serious, or somewhere in between.

Adam Kennedy, the author of the perl5 parser module Parse::Perl::Isolated seems to think that perl6 will be unparsable (at least of the technical sense of parsing, such as with YACC).

Here's the original post:
Will _anything_ be able to truly parse and understand perl?

The discussion continues here:
Lexing requires execution

I've been following perl6 development since 2000, and it's really evolving into a massive clusterhack. You have only to look at the Periodic Table of Perl Operators to get a feeling of how hypercomplicated the language is becoming. I think one of the underlying themes of perl6 is to provide a platform without limits, where any conceivable syntactic scheme can be implemented in the language. For example, perl6 will let you create operators of any unicode character and with any precedence. Things like that might be great for the writer of the code, but man, think about the poor sod who has to read and debug it later on!

EBay Bidding Strategies

The three fundamental Ebay bidding strategies. This must be a really popular little guide. The original page is gone, yet it's number one in google; only the cache remains.

Some excerpts:

Strategy 1: The Incremental (aka. Lowball) Bid
... If the bid is placed early, and the lowballer has the high bid for days, they could gain some emotional attachment to the object. The danger here is that they could very well be outbid in the late stages of the auction.
... By bidding early, other people who collect the same thing that you do could perform a search of your ID to see what you are bidding on. Then, they will follow you around from auction to auction and bid on the same item that you are bidding on. You do all the work, and if they have deeper pockets than you, they will get all of the benefits of it.

Strategy 2: The Proxy Bid
... There is one scam that allows someone to sniff out a proxy bidder's maximum bid. Someone could bid ridiculously high, taking the lead by one increment. Obviously, they could deduct by that lead what the proxy max is. Then, they retract with the "wrong amount" excuse.

Strategy 3: The Time-Awareness Bid (aka, the Snipe)
... If you snipe, you may receive e-mails from some very unsportsmanlike individuals belittling you for outbidding them. True, you still have won, but it can be annoying.

By the way, sniping is when you place your bid mere seconds before the auction ends, thus preventing anyone else from counterbidding in any way. You can autosnipe with a variety of sniping bots (google:ebay sniper).

Color Space Conversions

Formulas for converting from one colorspace to another. The whole gamut is here — RGB, HSV, CMYK, etc. The equations are presented in JavaScript, so it should be easy to convert to C, C++ or Java.

Material Selection Charts

This collection of two dimensional material property charts gives a good overview of the various qualities of different materials, from diamond to titanium to oak.

You can find some counterintuitive facts here. For example, silicon (the stuff computer chips are made of) is both stronger and stiffer than titanium. However, it lacks "toughness", the ability to absorb energy before cracking. (I guess that's why fighter jets aren't made of silicon.)

The charts compare density, toughness, elongation, cost, max temperature, stiffness, among other things.

(The JavaScript rollovers are a bit touchy; the mouse cursor has to be directly over specific words in the images.)

Link

Knuth's First Publication

Donald Knuth's first publication appeared in a 1957 issue of MAD magazine. It was titled "The Potrzebie System of Weights and Measures." Knuth was a high school senior at the time. Gif Images: Page 1, Page 2.
(filed under HISTORY)

Continuing Where I Left Off

Wow, it's been over 11 months since my last posting to AntiQuark. (See the MY OLD WEBLOG link at the lower right to access the previous incarnation.) I think I'll take another whack at this whole blogging thing. It's sort of fun in a way (when you have the time).

First Post

Test 2.
!