December « 2011 « Jim's Random Notes

Elephant on a trampoline

By Jim, on December 31st, 2011%

I laughed out loud when I saw this picture.

I was nine years old when Dad bought a trampoline. He had us check out some books from the library so we could learn the proper way to jump. I don’t know how much attention everybody else paid to those books, but I kind of . . . → Read More: Elephant on a trampoline

More threads makes the program slower?

By Jim, on December 28th, 2011%

Multithreading is A Good Thing. Many solutions can be structured so that you can bring multiple processor cores to bear on the problem, and you can get very close to linear increases in throughput. That is, your quad-core processor will complete a job four times as fast as a single-core processor. Or very close to . . . → Read More: More threads makes the program slower?

Writing a Web Crawler: Queue Management, Part 1

By Jim, on December 26th, 2011%

This is the fourth in a series of posts about writing a Web crawler. Read the Introduction for background and a table of contents. The previous entry is Politeness.

In the discussion of Crawling Models, I distinguished between two types of crawlers: “offline” crawlers that download documents and have a separate process create queue segments . . . → Read More: Writing a Web Crawler: Queue Management, Part 1

Short carving notes

By Jim, on December 22nd, 2011%

I haven’t given up on the carving. I’ve spent the last few weekends cutting up wood and making cutouts for those little birds. I enjoyed making those so much that I decided to send them to family and friends for Christmas. Last week I sent out a dozen, and I have more in the works.

. . . → Read More: Short carving notes

Writing a Web Crawler: Politeness

By Jim, on December 20th, 2011%

This is the third in a series of posts about writing a Web crawler. Read the Introduction for background and a table of contents. The previous entry is Crawling models.

When you’re writing a Web crawler, it’s important for you to understand that your crawler is using others’ resources. Whenever you download a file from . . . → Read More: Writing a Web Crawler: Politeness

The death of Kim Jong-il

By Jim, on December 20th, 2011%

The big news story today was the death of Kim Jong-il, leader of North Korea. Of all the commentary I heard, one idea struck me as rather funny in a “you’re more right than you realize” kind of way. I don’t recall who it was that NPR interviewed, but his comments were to the effect . . . → Read More: The death of Kim Jong-il

Writing a Web Crawler: Crawling Models

By Jim, on December 16th, 2011%

This is the second post in a series of posts about writing a Web crawler. Read the Introduction to get the background information.

Expectations

I failed to set expectations in the Introduction, which might have misled some readers to believe that I will be presenting a fully-coded, working Web crawler. That is not the case. . . . → Read More: Writing a Web Crawler: Crawling Models

Skip list revisited

By Jim, on December 14th, 2011%

In C# versus the data structure, I described the skip list data structure and the difficulty I saw with implementing it in .NET. I published a C# implementation a couple of months ago, and it did indeed suffer from excessive memory usage. It performed quite well, but the memory requirement of 100 bytes per node . . . → Read More: Skip list revisited

Writing a Web Crawler: Introduction

By Jim, on December 13th, 2011%

This is the first of a series of posts about writing a custom Web crawler. It assumes some knowledge of what a Web crawler is, and perhaps what crawlers are typically used for. I don’t know how many posts this subject will require, but it could be a rather long series. It turns out that . . . → Read More: Writing a Web Crawler: Introduction

Shopping for a monitor

By Jim, on December 6th, 2011%

I’ve put together a desktop computer to use for development at home, and I need to get a new monitor for it. The old ViewSonic 15″ LCD that we paid $1,200 for 10 years ago is still in good shape, but its maximum resolution of 1280 x 1024 is not big enough to do serious . . . → Read More: Shopping for a monitor

Sam Sheepdog and Ralph E. Wolf

By Jim, on December 5th, 2011%

Sam and Ralph were among my favorite Looney Tunes characters. I thought of them this morning when I said hello to my co-worker as I came into the office. So I thought I’d look them up on YouTube. Google is great. I searched for [wolf sheepdog looney tunes], and got the Wikipedia article.

All told, . . . → Read More: Sam Sheepdog and Ralph E. Wolf

Power carved tree ornaments

By Jim, on December 4th, 2011%

The latest issue (issue #57, Holiday 2011) of Woodcarving Illustrated Magazine has a pattern for a stylized bird that makes a great little tree ornament. I thought it would also be a good way to learn how to use my new Foredom power carver. So I spent some time with the bandsaw, cutting blanks from . . . → Read More: Power carved tree ornaments

Designing a better text file viewer

By Jim, on December 2nd, 2011%

Last time, I discussed existing text file viewers and why I find them inadequate. It’s disappointing that GNU less is the closest thing I’ve found to a good text file viewer for Windows. Functionally, less is almost perfect. For sure it blows away all of the other file viewers I’ve seen. Those other tools have . . . → Read More: Designing a better text file viewer

Large text file viewers

By Jim, on December 1st, 2011%

I’ve evaluated a lot of text file viewers for Windows, looking for one that has a decent user interface, a small set of “must have” features, and that can handle very large files.

One of the problems I have when looking for “large text file” viewers is that people have different definitions of “large.” Some . . . → Read More: Large text file viewers

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