Latest Posts

This is a pro­ject I’ve been work­ing on for the past quar­ter for my EE47 class. I didn’t want to make just a per­son­al mu­sic play­er, but in­stead a per­son­al mu­sic per­for­mance - and this is the more-or-less first pro­to­type of that. It could be de­scribed as a “vir­tu­al turntable”: you load songs in­to it, and then you can play them back as if they were on a record. You can slow down or speed up the record, or grab it and scratch it.

Read more about the de­tails of the im­ple­men­ta­tion on the class pro­ject page.

While shop­ping on Ama­zon and Newegg, I’ve come across a most frus­trat­ing prob­lem. Both web­sites of­fer a sort­ing fea­ture where you can view items in a par­tic­u­lar cat­e­go­ry usu­al­ly by price or name or re­lease date or things like that. Both al­so al­low buy­ers to rate items after they’ve used them, and al­low po­ten­tial buy­ers to sort the items based on other cus­tomers’ re­views. There is a fair­ly frus­trat­ing prob­lem with this sys­tem, how­ev­er.

Both Ama­zon and Newegg (and pre­sum­ably thou­sands of other on­line stores) sort by av­er­age cus­tomer rat­ing when told to sort by rat­ing. If I were shop­ping for, say, com­put­er mon­i­tors on Newegg, and I was look­ing for one that was re­li­able and rat­ed high­ly by a lot of peo­ple, the av­er­age rat­ing sys­tem might be mis­lead­ing. Say there is an HP mon­i­tor for sale, which 500 peo­ple bought and liked. One per­son, how­ev­er, bought it and found a few dead pix­els (man­u­fac­tur­ing de­fect - it hap­pens), and so rat­ed it low. The mon­i­tor’s av­er­age rat­ing would be 4.98 out of 5.00 or some­thing like that.

Now con­sid­er a no-name mon­i­tor that one per­son bought and liked. He or she is the on­ly per­son to have ev­er rat­ed this mon­i­tor, and rat­ed it a 5, mak­ing the mon­i­tor’s av­er­age rat­ing 5.00. 5.00 for this no-name mon­i­tor is high­er than 4.98 for the HP mon­i­tor - this would put the no-name mon­i­tor high­er up on the list if I asked Newegg to sort by “Best rat­ing”.

For a se­lec­tion of two prod­ucts this seems like a mi­nor prob­lem, but if I were look­ing for, per­haps, a new DVD burn­er, the hun­dreds of prod­ucts which re­ceived two or three 5.00 re­views would fill up many pages of my search with ir­rel­e­vant prod­ucts - I would not con­sid­er one or two peo­ple rat­ing a pro­duct a 5.00 to be an ac­cu­rate indi­ca­tion that the pro­duct is, on the whole, re­li­ably con­struct­ed. I would have to wade through all those pages be­fore I found the first pro­duct rat­ed by more than about five peo­ple.

There must be a bet­ter way to sort prod­ucts by cus­tomer rat­ing than sim­ply by av­er­age rat­ing, which pro­duces mis­lead­ing re­sults. Newegg’s sort by num­ber of rat­ings is bet­ter but still not ex­act­ly it. What if five hun­dred peo­ple bought a pro­duct and rat­ed it bad­ly? I think a bet­ter so­lu­tion might be some sort of weight­ed av­er­age - 4.98s can be pulled high­er than 5.00s if they have more rat­ings. Some­thing along the li­nes of (score * num­ber-of-re­views), so that the 500 5.00s that the bet­ter pro­duct re­ceived counts more than the two 5.00s that the in­fe­ri­or pro­duct re­ceived.

Here is an orig­i­nal com­po­si­tion I wrote, called Grace, for flute, clar­inet (in Bb) and pi­ano, based some­what on the hymn “Amaz­ing Grace”. I’m pro­vid­ing it for free, un­der copy­right, but if you de­cide to per­form it, I would ap­pre­ci­ate it if you would let me know!

Grace (PDF)

(Up­date: in ret­ro­spect, I have re­al­ized that this ar­ti­cle is per­haps not so well writ­ten. Ex­pect some­thing more use­ful and co­her­ent soon!)

Lin­ux seems like the per­fect so­lu­tion for the new brand of portable PCs, net­books. It’s ef­fi­cient, re­quires few re­sources, and can run most if not all of the pro­grams one usu­al­ly runs on such small com­put­ers - word pro­cess­ing, email, web brows­ing, and so on. Large, com­plex soft­ware pack­ages that re­quire Win­dows to run per­form abysmal­ly on low-pow­er com­put­ers like net­books, so ef­fec­tive­ly the need to run Win­dows is nul­li­fied.

Why, then, do con­sumers (and re­view­ers!) choose Win­dows over Lin­ux for net­books? Read more…

It doesn’t work.

Okay, that’s a lit­tle bit un­fair; it’s prob­a­bly more ac­cu­rate to say that it doesn’t work as ex­pect­ed. The Tu­niq Sanc­tum hard drive en­clo­sure is a 5.25” bay de­vice that holds a 3.5” (or small­er, I sup­pose) hard drive, and pur­port­ed­ly not on­ly re­duces the noise out­put of the drive but al­so helps to keep it cool. This de­vice, un­for­tu­nate­ly, ex­cels at one aspect of its claimed pur­pose and fails at the other. While it does in­deed keep noise levels down very ac­cept­ably, the Tu­niq Sanc­tum en­clo­sure, due to the lack of air­flow in­side the de­vice, fails to cool the hard drive ad­e­quate­ly. In fact, leav­ing the hard drive in­side the en­clo­sure will prob­a­bly de­crease the hard drive’s life­time due to the 60+ de­grees Cel­sius tem­per­a­tures some­times ex­pe­ri­enced in­side the de­vice. Read more…

There’s been a lot of talk re­cent­ly about why PC gam­ing is “doomed”, main­ly be­cause of the ev­er-grow­ing amount of PC game pira­cy. I don’t nec­es­sar­i­ly think that PC gam­ing is doomed at all, although I do think there will be a sig­nif­i­cant shift in the way the PC game mar­ket works - to­wards a more con­trolled dis­tri­bu­tion mod­el, per­haps, like Steam.

This is what I think about pira­cy, how­ev­er. It’s a self-sus­tain­ing cy­cle, in a way: high video game prices en­cour­age gamers to pi­rate games in­stead of buy­ing them, “forc­ing” video game man­u­fac­tur­ers to raise prices or keep prices high in order to not lose rev­enue. Those high prices in turn con­tin­ue to en­cour­age pira­cy. This loop is not nec­es­sar­i­ly un­break­able, though there are sev­er­al fac­tors that, in my opin­ion, con­tribute to its sus­te­nance: Read more…

This is a neat trick I found in Fire­fox. This works at least in Fire­fox 3 and may al­so work in Fire­fox 2; I do, how­ev­er, en­cour­age you to up­grade if you’re still us­ing Fire­fox 2, as the third re­lease brings about many need­ed en­hance­ments in per­for­mance and mem­o­ry usage. Us­ing a book­mark, one can turn the lo­ca­tion bar in­to a sort-of com­mand parser, there­by cre­at­ing a sort of “key­board short­cut” for that book­mark. This in ef­fect al­lows you to cre­ate your own cus­tom “key­board short­cuts” or “lo­ca­tion bar com­mands”. Here’s an ex­am­ple of how it works. Say I want to cre­ate a short­cut for Google Im­age Search. I can go to the Im­age Search page, and right click the box, and se­lect “Add a key­word for this search”:

En­ter some name for your search; the name doesn’t mat­ter. (Al­ter­na­tive­ly, you could sim­ply cre­ate a new book­mark; its tar­get (“lo­ca­tion”) should be some­thing like http://www.google.com/search?q=%s, where %s rep­re­sents what will be searched on. Right-click the book­mark you just cre­at­ed and click “prop­er­ties”.) This di­alog box will pop up:

In “key­word”, type the “com­mand” that you wish to use to ac­cess this short­cut. In this case, I would use some­thing like “imgs” or “is”. One-let­ter key­words do not seem to work very well. On­ce you have en­tered the key­word and closed the di­alog, you can type in the lo­ca­tion bar (press CTRL+L to get there quick­ly):

imgs cute pup­pies

Press en­ter, and be­hold your search un­fold­ing be­fore your eyes.

Here is the up­dat­ed ver­sion of my pre­vi­ous au­then­ti­cat­ing/for­ward­ing Squid 3 con­fig. It adds some things and fix­es some things. In par­tic­u­lar, the peer ex­clu­sion rules from the pre­vi­ous con­fig were not work­ing - this one should cor­rect­ly not use the par­ent prox­ies when query­ing “lo­cal ad­dress­es”. As be­fore, the con­fig­u­ra­tion file con­tains two proxy servers for load bal­anc­ing; it can be ex­tend­ed easi­ly to in­clude more. Read more…

Last time I wrote about try­ing to find ca­su­al games for medi­um/large-group so­cial events. We can split mul­ti­play­er video gam­ing in­to a cou­ple of vague­ly-de­fined cat­e­gories; I’m go­ing to use the term “ca­su­al” or “so­cial gam­ing” to refer to medi­um-scale so­cial gath­er­ings that in­volve video gam­ing; hard­core gam­ing, of course, is all about the game; and we might per­haps call the last group “LAN par­ty gam­ing” to indi­cate a mid­dle ground be­tween ca­su­al gam­ing and su­per-in­tense gam­ing.

It is for the first cat­e­go­ry, so­cial gam­ing, that I sug­gest a game to­day: Heroes of Might and Mag­ic III. Read more…

This is a mouse that was on­ce bro­ken but is now healed. (A me­chan­i­cal switch on the cir­cuit board was bro­ken; upon fix­ing that, the mouse works al­most like-new.) I was ac­tu­al­ly quite sur­prised at the ex­treme sim­plic­i­ty of the ac­tu­al mouse hard­ware - a cou­ple of re­sis­tors, ca­pac­i­tors, an LED for the sen­sor, and the sen­sor chip it­self. It seems to me that the costs for build­ing such a mouse must be rather cheap in­deed. In fact, I won­der now about the op­ti­cal track­balls out on the mar­ket to­day - mine (the Kens­ing­ton Ex­pert Mouse) is to all ap­pear­ances just an up­side-down op­ti­cal mouse with a ball and a cou­ple of ex­tra but­tons; would it be per­haps pos­si­ble to con­struct my own per­fect­ly-func­tion­ing track­ball with on­ly cheap op­ti­cal mouse parts?

Fas­ci­nat­ing as that may seem, there are in­deed more ex­cit­ing pro­jects to at­tend to first.