Author Archives: dara

AT&T Wireless Woes

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I finally got my housing assignment from the university last week (I was waitlisted).  Pretty nice place if I do say so myself.

Only one problem: I don’t get any cellular reception in the apartment.  I’m not talking about having 1 or 2 bars and suffering dropped calls.  I’m talking about no reception whatsoever.  Oh sure, if I open a window and lean out at the right time of day, I might get 1 bar.  On a good day.  If I’m lucky.  Other than that I get nothing.

My first instinct was to blame AT&T.  After all, it’s AT&T that had a huge dead zone in the middle of campus at my last school, and it’s AT&T that offered almost no coverage at home back in California.

Apparently, my instincts are correct.  My roommate, who also has AT&T, has the same problem.  My neighbor, who has Verizon, has no problem at all.

So naturally, I called AT&T to complain.  Their suggestion, after I had spent a nice chunk of the afternoon on hold, was to purchase a ‘MicroCell tower’.  This device which attaches to your internet connection, acts as a cell-phone booster and re-routes cellular communications over your network.

Here’s the problem: I’m already paying AT&T monthly (~$65) for service.  Now they want me to pay $60 in addition, just so I can use the service I’m already paying for?

Thanks, but no thanks.  Goodbye AT&T.  Somehow, I don’t think I’m going to miss you.

I’d rather not be the product

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Google adwords

Google is one of the great success stories of the last decade.  The explosion of the internet has left them at the center of the one sector of the economy that seems to have a future.  In addition to producing Google search, they are one of the companies that is putting significant resources into research that may not have immediate applications.  They’re also from what my friends tell me a fun and exciting place to work.

The thing that surprised most people about Google’s services early on is that they’re free.  Or rather, that’s how it seems to us.  We get to access great resources day in and day out without spending a penny.  Seems like a good deal.

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MacOS X 10.7 Lion – some comments

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Lion

I’ve used Macs since about 1992, and I’ve probably at one point or another tried every major release of an Apple operating system, including such lesser-known items as A/UX and Rhapsody (RIP).

My favorite release for a long time has been OS X 10.3 (a.k.a. Panther), which served as my primary OS for 3 years on a PowerBook G4 during my time at Stanford.  Aside from the cool codename, I liked Panther primarily because it fixed almost all the major problems with the previous releases, sped up performance, and otherwise kept out of the way.  Sure, it was easy on the eyes, but it didn’t have the huge amounts of marginally useful eye-candy that became the norm around the time Windows Vista and OS X 10.4 came out.

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The Trouble with Small Cameras

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Cameras

I’ve had an Olympus XZ-1 for almost half a year now as my ‘carry-everywhere’ pocket camera.  By most folks’ standards, it’s a large ‘compact’ camera.  Compared to my Nikon D700 SLR though, it’s a decidedly more travel-friendly companion.  In fact, when I went to England in June, I took both cameras, and ended up actually using the Olympus more, largely due to the convenience (when it rained, it was easy to quickly stick the XZ-1 in a waterproof plastic bag in m pocket, unlike the D700).

The usual knock on compact cameras is that the image quality, particularly when the light levels drop, don’t match up to their larger brethren.  There’s a fairly simple explanation for this: the sensor in your average high-end digital compact is less than 40mm^2.  The size of the sensor in your average DSLR is 350mm^2.  Since the sensor’s purpose is to gather and record light, the smaller sensor records less light, and the less light you record, the less information your image has.  In reality, things are a bit more complicated, but that’s the basic idea.

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A Dash of Color

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Colorful

A good friend was in town to look at business schools.  I took the afternoon off to wander about central Manhattan, camera in hand.  We started at the main Columbia campus, meandered through Central Park, and ended up on the west side.  I came across this particular building around 90th street.  The long hot summer has finally moved on, leaving the sort of cool crisp weather that makes fall my favorite season in NY.

2011 MacBook Air – a (fairly) brief review

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Thin is in

My beloved ThinkPad X61 stopped working reliably over the summer.  The AC adapter broke in England, to be partially resurrected through the creative use of a q-tip and some tape (wiring out of the brick had frayed).  The fan was already semi-nonfunctional, leading to the occasional heat-induced spontaneous hibernation.  When the screen started displaying random pixel noise after every 3 or 4 reboots, it seemed like a good time to look for a replacement.

The obvious choice was a MacBook Air.  Like the ThinkPad, it was a thin, light machine.  Unlike the ThinkPad, it did not saddle me with Windows (or no battery life, if I used Linux).  The main drawbacks seemed to be the lack of expandability (my ThinkPad had a dock with just about every port a person could want) and the slowish low voltage processor.  When Apple updated the Air in July to the newer Sandy Bridge CPU, I jumped and ordered the least expensive 13″ model.

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Compare and Contrast

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I do a fair amount of walking and hiking when time permits.  For the last 2 years or so, I’ve been taking my Nikon D700 camera along on most of those trips.

The D700 is considered by Nikon to be their lower-end professional model.  When it came out, it basically offered the same sensor and performance as their top-of-the-line D3, but for $2000 less in a more compact body.  The D700 was missing a few features compared to the D3, but on the basic criterion of image quality and operating speed it is essentially the same camera.  In short, it is (or given the speed of digital development, was) a pretty fancy camera.

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A Transportation Gripe

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As I haven’t found a place to stay yet near school, I’ve been commuting in to New York City for the last few weeks.  The distance from Hartsdale to Columbia is about 20 miles by.  Without traffic, it’s a half hour trip.  Even with traffic, it’s usually less than an hour.  The same trip, via public transportation, averages an hour and a half.

To get downtown using mass transit, the first problem is getting to the train station.  I’m staying about 3 miles from Hartsdale station, 2 blocks from one busy road, and 3 blocks from another.  The good news is that there’s a bus.  The bad news is that the bus runs 3 times in the morning (6, 6:30 and 7:00) and 3 times in the evening (5:00, 5:45 and 6:30).  It takes roughly 20 minutes to make the 3 mile trip.

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Optimizing Huffman, part 3

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So far, we’ve found a number of fairly low-cost (in terms of code and complexity) ways to tune the Huffman program for better performance.

Still, after thinking about the problem for a bit, I did see some other potential areas for improvement.  In particular, the fact that the encoding process was being done essentially bit-by-bit (appending 1 bit at a time to the buffer) seemed inefficient.  If there was only some way to append a whole bunch of bits at once (i.e. the entire encoding for a given character)…

simplehuffman4.c does precisely this.

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