Monthly Archives: January 2008

Using your phone as an e-Book reader

There has been a lot of buzz lately about the Amazon Kindle and the Sony Reader — new electronic-paper-based e-book readers that have a variety of features and advantages. Great. However, they’re both expensive. More annoyingly in my mind, they are also an additional device to lug around and keep charged. They will let you read all kinds of the latest and greatest stuff, I must admit.

However, what if you already had a good device for reading e-books? What if you wanted to read some classics or books released under Creative Commons licenses on it? Then you would be in luck!

A couple of months ago, Molly sent me a link to a new book released under a Creative Commons license, called Postsingular. A link from the book’s page led me to Books In My Phone. This site takes Creative Commons books and those out of copyright, loads them into a simple and effective e-Book reader that runs on J2ME, and makes it possible to download them directly on to your phone. I have so far read Postsingular, Walden, and part of Moby Dick on my phone, and am happy to report that it was a pleasant and engaging experience.

The reader is fairly well written, except for one thing. If you hit the back key when you have just opened the book, it loses your place and goes back to the beginning. This is not so awful as it sounds, for it is easy to skip from chapter to chapter and from page to page. Aside from that glitch, it’s easy to change the font size, page up and down, and (as mentioned) skip around the book. The reader is entirely self-contained (J2ME aside), and (with a few quirks) remembers your place when you exit!. This last item is overlooked in many readers and prevented me in the past from using my Treo devices to read e-Books.

Therefore, if you enjoy reading while waiting, commuting, or even in a bed or a chair, I recommend that you try reading something from Books In My Phone. If you like sci-fi, Postsingular is not a bad place to start.

Also, let me know if you find any books there that you’d like to recommend!

Using UNIX (and Linux) for Research in silicio

There is a rank list of the most powerful computers on the planet: Top500.org. (It looks like they’ve recently done a site redesign for the better.) Statistics on these computers are available here. Of the top 500 most powerful computers on the planet, a measly 1.20% run a non-UNIX operating system (OS). 76.20% run an unspecified Linux (compared with, say a certain version of Red Hat or SuSE linux). According to the overall family rankings here, a total of 85.20% run some variant of Linux. The remaining operating systems on the list are all various UNIXes, including BSD and Mac OS X.
Continue reading →

Request for Critiques

I would like to improve my blog writing. As far as I know, my English is generally correct. While I welcome grammatical and spelling corrections, I am seeking critiques of my writing style specifically. I’ve read a few books on how to improve one’s writing style, and I have subscribed to some blogs that espouse ways of improving one’s writing, but what really matters is how my readers feel about my writing.

After discussing this with my wife (my first critiquing recruit), what I’m specifically looking for are answers to these questions:

  • What percentage of the posts on this site do you read in their entirety? Rough estimates (say, to the nearest 25%) are fine.
  • Why do you skip or just skim some posts?
  • If you are reading a post and suddenly lose interest, do you know why? Too much jargon? Train of thought too hard to follow? If you are so generous as to volunteer some critiques, please pay special attention to this in the future, and comment on the relevant post when it happens.

What have you noticed?

NEMA plug types

L21-30P image from Wikipedia

As I mentioned in my “Five years in the lab” post, over time I’ve become the de-facto system administrator for the lab. With no formal system administrator training (though I’ve taken many computer science and computer engineering courses), every once in a while I’ve had to overcome a major hurdle of a knowledge gap.

The most recent hurdle, encountered when we moved into our new building and server room, was plug types. There are a ton of plug types, and even my background in Circuits I and Circuits II was not enough to make things readily apparent. I actually find it pretty interesting — enough to write a post about it.

There are four parts to a NEMA plug type (or connector) name:

  1. Locking: If the plug can be twisted to lock it in the socket, a capital “L” is appended to the beginning of the name
  2. NEMA number: This is an arbitrary numbering scheme, and indicates the voltage and phase. For example, “5” means 125 volts with a ground wire and “6” means 208 to 250 volts with a ground wire. “21” is a more exotic example, indicating three-phase power.
  3. Current Rating: The maximum current in amperes that the plug and circuit are rated for. Typical numbers are 15, 20, and 30.
  4. Plug or Receptacle: A “P” for “plug” or “R” for “receptacle” may be tagged on to the end of a designation when the corresponding part is being referred to.

To put these all together for some common examples, we have:

  • 5-15P: The common plugs found on most modern (and grounded) appliances
  • 5-20R: 120V receptacles that can supply up to 20A. Often these have a “T”-shaped slot that will take either the 5-15P (above) or a 5-20P (one prong rotated 90 degrees). Most of the receptacles in the new CSE building have this “T”-shaped socket.
  • L5-30: Locking plug that is the standard for shore power for boats (120V/30A). Note that the “L” does not refer to the black screw-down ring usually present on these cords. That’s an optional add-on. It refers to the locking done by twisting the plug within the socket.
  • TT-30: Cementing the arbitrary nature of the NEMA “number”, the “TT-30” is the standard 120V/30A plug for “all but the largest” recreational vehicles. This is also known as an “RV-30”.

Our new cluster takes 8 L21-20 receptacles and a few L5-15 or L5-20 receptacles (for the battery back-ups). We have a really old battery back-up that we plan to use again, and for that we need an L6-30R installed.

While trying to sort all of this out, I really wished that the NEMA designations were more directly informative about voltage and phase. Would 120-1-30 be so much more difficult to write than 5-30? What about 250-3-20 vs. L21-20? Have you ever encountered an uncommon plug type in a data center or other building?