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Showing posts from November 14, 2010

Logitech Trackball Mouse Reviews

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Perm url with updates: http://xahlee.org/Periodic_dosage_dir/logitech_trackball.htmlLogitech Trackball Mouse ReviewsXah Lee, 2009-12-24, 2010-11-02, 2010-11-21Logitech Wireless Trackball M570“Logitech Wireless Trackball” amazon This is their latest product. Just came out in 2010-09.This is a improvement over the classic “Logitech Trackman Wheel” (the red ball). Here's major improvements:A scroll wheel! Excellent.2 extra programable buttons. (used for example for next/previous page history for browser) This is extremely convenient.Laser tracking tech. (as opposed to “optical” using LED. Laser offers more precision.)Wireless.Tiny USB receiver.Overall, it got positive reviews. However, compared to the classic “Logitech Trackman Wheel” (red ball), the ball is smaller and is a little more stiff to spin. This is also twice as expensive.Review of “Logitech Wireless Trackball M570” by jared0x90. Logitech Trackman Wheel“Logitech Trackman Wheel Optical”. amazon The “Logitech Trackman Wheel Opt…

Using iframe to Embed Youtube Videos

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Perm url with updates: http://xahlee.org/js/youtube_iframe_embed_video_code.htmlUsing iframe to Embed Youtube VideosXah Lee, 2010-11-19In 2010-07, Google introduced a new html format for embedding youtube videos.This is the original: <objectwidth="480"height="385"><paramname="movie"value="http://www.youtube.com/v/h7XjOK_DSmo?fs=1&amp;hl=en_US&amp;rel=0"></param><paramname="allowFullScreen"value="true"></param><paramname="allowscriptaccess"value="always"></param><embedsrc="http://www.youtube.com/v/h7XjOK_DSmo?fs=1&amp;hl=en_US&amp;rel=0"type="application/x-shockwave-flash"allowscriptaccess="always"allowfullscreen="true"width="480"height="385"></embed></object> The following is manually crafted code using valid html with “object” tag: <objecttype="application/x-shock…

Best Mouse For Programers

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Perm url with updates: http://xahlee.org/kbd/razer_naga_mouse.htmlBest Mouse for Programers and AutoHotkey Keyboard MacrosXah Lee, 2009-12-18, 2010-11-19While shopping for a gaming mouse, a interesting one i noticed is the “Razer Naga MMOG Laser Gaming Mouse”. This mouse has 17 buttons!“Razer Naga MMOG Laser Gaming Mouse” amazon At first i thought this would be the most stupid mouse. I thought that, some geek thought more button is better, so idiotically jam'd the mouse with cellphone number keys. The result would be very painful to use. However, from reading amazon.com's reviews, apparently it is usable.Thinking about it for a while, i think this could be actually a very good mouse. The buttons probably can be operated by touch without sight easily for at least half of the number buttons. Razer Naga Review Why You Need 17 Programable Keys?When this mouse first came out in 2009, the number keys are not programable. But with version 2 of driver, they are programable now! So, a m…

What's Mouse DPI and Does It Matter in Real-Time Combat Gaming?

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Perm url with updates: http://xahlee.org/kbd/mouse_dpi.htmlWhat's Mouse DPI; Does Mouse DPI Matter in Gaming?Xah Lee, 2010-11-19, 2011-01, 2011-04-22Spent about 6 hours tech geeking on mouse again. Watched quite a few youtube videos on reviews of various gaming mouses.About mouse, there's something i never understood completely. That's DPI (dot per inch). If a mouse has 800 DPI, supposedly it means: if you move your mouse one inch (2.54 cm), the mouse will be able to send 800 signals. However, it's much more complicated than that.There are these issues involved:There's USB poll rate (aka USB Report rate) Doesn't matter what's your DPI, if the mouse is using USB interface, the USB will get input from the mouse at a fixed rate. (Windows default is at 125 Hz) (actually, it's more complicated than that. It seems that USB has different protocol. One of them does not rely on regular poll, but i read that nobody uses that because it's more expensive.)There…

Emacs Keyboard Macro Example: Adding HTML Attribute

Perm url with updates: http://xahlee.org/emacs/emacs_macro_example2.htmlEmacs Keyboard Macro Example: Adding HTML AttributeXah Lee, 2010-11-18This page shows a real world example of emacs keyboard macro use. If you are not familiar with keyboard macro, see: Emacs Keyboard Macro and Examples.ProblemI have a html page of Printed References On Plane Curves. In that page, there are a list of 34 books with this html format: <spanclass="title">Geometry: Euclid and Beyond</span> <aclass="amz"href="http://www.amazon.com/dp/0387986502/?tag=abc-20">amazon</a> I need the amazon link to contain a “title” attribute. Like this: <spanclass="title">Geometry: Euclid and Beyond</span> <aclass="amz"href="http://www.amazon.com/dp/0387986502/?tag=abc-20"title="Geometry: Euclid and Beyond">amazon</a> To manually fix this, i use isearch to find a amazon link, then search backward looking for…

Criticisms on Criticisms on a New Kind of Science

Perm url with updates: http://xahlee.org/cmaci/ca/criticisms.htmlCriticisms on Criticisms on a New Kind of ScienceXah Lee, 2007This page is a criticisms on criticisms on the book 《A New Kind of Science》.Words Wolfram Likes to UseSome words Wolfram likes to use in his writings: fundamental, quite, rather, “it turns out”, “kind”. Usually used in a manner to qualify his sentence so that it is still true in a broader, general context, but often just makes his statements hazy. Here's a typical example from p170: “... adding more dimensions does not ultimately seem to have much effect on the occurrence of behavior of any significant complexity.”. Non-Standard Terminology and NotationThe following are from: 〈Critical Review of “A New Kind of Science”〉 (2002-07-12), by David Drysdale.Part of the problem is Wolfram's insistance on using his own terminology for concepts and ideas that have perfectly good names in regular mathematics and science. Examples: he always referring to fractals …

Emacs Keyboard Macro and Examples

Perm url with updates: http://xahlee.org/emacs/emacs_macro_example.htmlThis page shows you how to use emacs keyboard macro feature, with several examples of real world use.How to Record a Sequence of Keystrokes?The keyboard macro (kmacro) feature that lets you record and playback keystrokes. The key strokes can include calling emacs commands or commands that execute any emacs lisp functions.To record keystrokes, press 【Ctrl+x(】 (“kmacro-start-macro”), then start typing your keystrokes. When done, press 【Ctrl+x)】 (“kmacro-end-macro”). This records your keystrokes. If you made a mistake, you can cancel 【Ctrl+g】 (“keyboard-quit”) and start over.To run the keystrokes you've just recorded, press 【Ctrl+xe】 (“kmacro-end-and-call-macro”) or call “call-last-kbd-macro” or “apply-macro-to-region-lines”.Command NameKey“start-kbd-macro”【Ctrl+x(】“end-kbd-macro”【Ctrl+x)】“kmacro-end-and-call-macro”【Ctrl+xe】“call-last-kbd-macro”◇“apply-macro-to-region-lines”◇Saving Your Keyboard Macro for Future U…

Mathematica 8 is released

Mathematica 8 is released.Announcement from Stephen Wolfram: http://blog.stephenwolfram.com/2010/11/mathematica-8/.New features: http://www.wolfram.com/mathematica/new-in-8/Impressive free form english input feature. http://blog.wolfram.com/2010/11/15/the-free-form-linguistics-revolution-in-mathematica/comment-page-1/I got Mathematica 7 this month, as a gift from Wolfram Research. (before they released 8) (Thanks Wolfram) I haven't actively been coding Mathematica since about 2000. In the coming months, i'll update my tens of Mathematica packages on my site to Mathematica 7.Mathematica started in 1988 as a so-called computer algebra system. Namely, it lets you do things like solve equations, factor polynomials, do integration, derivative, etc. But, due to Stephen's design, it is also a full featured general programing language, much based on lisp. (he probably would not admit it) But since about late 1990s, Mathematica is more marketed as a technical computing platfrom — a…

ErgoEmacs keybinding new version released! At v5.3.7.

A new version of ErgoEmacs keybinding is out! At v5.3.7. Feature highlight:Added open-in-desktop command with key 【Ctrl+Shift+O】.Added Danish layout. Thanks to Michael BuddeAdded ergoemacs-layout-pt-nativo.el. Thanks to Xavier PinhoDownload: ErgoEmacs keybindings v5.3.7 (Released on 2010-11-15, tested with emacs 23.2.1.)Visit home page for detailed info: ErgoEmacs Keybinding.