laptop on S Anand

Laptop power usage

Sun, 07 Feb 2010 18:09:29 +0000

I just got a digital wattmeter. Had no idea about these until Google PowerMeter, but now, they’re all the rage. Mine’s a pretty simple model and all I plan to do with it is play around with a few household gadgets.

My first target, obviously, was my Dell Latitude E5400. The statistics are interesting:

Power	… when…
0.3W	Laptop is switched off. The adapter must be consuming the power
1.3W	Laptop is on standby.
12W	The lid is closed, and no applications are running.
18.5W	The laptop is on, the lid is open, and no applications are running
25W	The laptop is writing to the hard disk
34W	One CPU is fully utilised
41W	Both CPUs are fully utilised

Looks like the display and hard disk each consume about 6.5 watts each, while the CPU consumes a whopping 15 + 7 = 22 watts.

One interesting observation is that the colour of the display doesn’t make much of a difference. From my CRT monitor days, I’d remembered that a black screen consumes less power, and is less likely to wear the screen off. So my desktop background has always been black, and most of my applications use a black theme. But it turns out that on LCDs, it makes absolutely no difference. A full white screen uses the same power as a full black screen. So I’ve really been wasting my time the last 9 years. (There is a good reason to have a black screen, sometimes – it’s much easier on the eyes when reading without lights.)

Another lesson was that turning off the wireless had no effect whatsoever. (It worked quite well for my Blackberry, though. Increased the battery life quite a bit. I thought the same might apply for laptops, but looks like it doesn’t.)

I’ll do an audit of some of my home appliances and post it out here. Wonder if there’s a repository of power usage for appliances…

Comments

Dibyo 8 Feb 2010 3:15 am: I have always run a laptop battery longer by putting the wireless off, the difference is immediate, so this is NEWS TO ME! This is how I figured it - point at battery icon (e.g. 50 mins left) - switch off wireless - point a min later (1 hour left). What was I doing wrong?
JB 8 Feb 2010 5:25 am: Informative. I should buy one as well as show this to my roomies, who leave their personal laptops lid-opened throughout the day and night while sleeping or away to office. Thanks.
Nikhith 8 Feb 2010 5:44 am: I have one doubt about the way u conducted these tests and deduced the results Mr. Anand. I’m sure u could use the power meter only to check the power usage when u connected the charger. But the power strain on the charger due to white background and wireless on, is much less significant as compared to the power strain on the batteries alone. So i guess there will considerable increase in the battery backup due to black background and wireless off. I’m just hypothesizing this, and this must answer u r question too Dibyo
S Anand 10 Feb 2010 5:06 pm: @Dibyo: just to be sure, I tried it again. Definitely no change in power consumption when the wireless is turned off. Not sure if the problem is with how Windows calculates the power consumption, or whether your laptop’s wireless is different somehow…
S Anand 10 Feb 2010 5:09 pm: @Nikhith: If that were the case, changing the display’s brightness shouldn’t have affected much either. But for every notch that I darkened the display, the power consumption fell visibly by about 0.5W. So I suspect the actual usage of the laptop is directly transmitted to the mains, and the battery doesn’t really do much of a buffering. (At least when it’s charged, I guess. Mine was fully charged.) This means that the the wireless power consumption really is insignificant compared to CPU usage, brightness, or hard disk usage.
Amit 22 Mar 2010 3:32 pm: thanks Anand for sharing the experiment result. As per my understanding, with wireless switch on battery consumption is higher. many times my laptop’s battery has dried very fast because by mistake I have left the wireless switch on. you can also validate this by just leaving machine for sometime on battery power with/without wireless switch on ( dont use the ac power).
Rajesh 25 Mar 2010 11:13 am: Where can I get this gadget in India?
S Anand 25 Mar 2010 4:18 pm: You know, I’ve been hunting all over Bangalore and Chennai for it. Yet to find one!
Raj 24 Feb 2011 7:10 am: Wonderful information. No one has given this much clarity on this topic. Keep going. Thanks R@J.

Reading books on a laptop

Fri, 22 Feb 2008 12:00:00 +0000

I have the habit of reading books on the screen. It’s something that started from the early 90s, when I got a copy of The MIT Guide to Lockpicking. Since I didn’t have access to a printer, I’d spent hours poring over the document on the screen. And then I discovered Project Gutenburg…

I’ve heard many people ask if I have a problem with this. Personally, no. I’ve been staring at screens from the age of 12, and I’m quite used to it. My job requires me to stare at a screen for most of the day anyway. (I’m not saying there’s no a strain on the eye. My eyes are red at the end of the day. I don’t know if they would be less red if I’d been staring at paper instead of a screen. But my glasses have remained roughly the same power over ~15 years, so it’s probably not ruining my eyesight much.) For those who are like me who reads all the time and spends a lot of more time facing their laptops, you might want to check this sd card, a very good quality card that can be handy in the future.

To me, the main advantage of a book is that a book is a lot easier to handle.

You can fit a book into your bag, sometimes into your pocket.
You can hold it in your hand comfortably – it’s easy to grip, and light.
You can open it instantly (no need to boot up).
You can bookmark it (or even just remember the last page number) and quickly flip to that

None of these is possible on a computer.

Or is it?

On a desktop, I agree – it’s impossible to read for long. Your back would kill you. I’ve done it for many years, and it’s not worth the pain. With a laptop, however, you can lie down on the bed or sofa and read. It’s a huge advantage. (For just this one reason alone, I’d suggest that everyone buy a laptop.)

As for carrying books, I carry my laptop to work every day, so there’s no incremental burden. But if you weren’t doing that, it’s probably not a great idea. When I travel on weekends, I’d much rather take a physical book than a laptop. This is probably the single biggest problem with a laptop – that it doesn’t travel as easy as a book.

That’s probably offset by the advantage that a laptop isn’t really a book – it’s a library. I don’t need to decide which book to read. I can bring them all along, pick what I like, and when I’m done, move on to the next. And I’m not restricted to books. I have a fairly good collection of movie scripts and comics. Depending on how long I have on the train, and my mood, I can pick between these.

One thing that makes a laptop a lot easier to use is to rotate it.

If you hold the laptop this way, it’s surprisingly easy to handle. I find that I can read this way even when standing on a crowded train — which is as much as I can expect from any book. (Strangely enough, it doesn’t seem to attract too much attention on the train either.)

If you have a decent graphics card, you can rotate your screen using the graphics properties. (I’m sure there are are hotkeys to do this. My two-year old daughter somehow knows them, and manages to turn the screen upside down in a fraction of a second, while I spend then next 5 minutes struggling to restore an upside-down screen.)

If not, you can just use a PDF reader (like FoxIt, which is better than Acrobat Reader) to rotate the page by 90°.

A laptop takes care of the problems of bookmarking and load time as well. I usually leave mine on hibernate, and it takes about 10 seconds to open up to where I left off. Sometimes I just leave the laptop on in the bag — for example if I’m changing trains.

The other solution, of course, is to try an ebook reader. Given my laptop, I haven’t tried one. But other than the ease of holding it, there’s no big I see.

The other question is, how do you find ebooks?. Other than buying them, I find that the easiest option is to search on Google. A surprisingly large number of them are indexed.

Here’s a custom search engine for ebooks.

Comments

jake 22 Feb 2008 12:00 pm: I agree with you. I have been reading books on the computer screen for many years now. A laptop has the advantage that is has better contrast and the screen doesnt flicker. A crt with a badly set screen refresh rate can be quite a pain. I have found that the refresh rate on a crt for example has to be as high as your monitor will allow (75hz and above) for a given resolution, for your eyes to be completely comfortable. I’d also recommend anti glare screen. The LCD screens on a laptop dont have all these issues. Also one has to make sure there isnt any light reflecting off your screen into your eyes, and that the contrast and luminosity of your screen holds up even in bright light conditions. For all these, a real book is the perfect thing. The contrast of clearly formed letters over a clear paper background is the let work for your eyes. Ofcourse one can enable anti-aliased fonts like clear type and try reading on a terminal. A favourite way for me to read is on a text browser in a terminal. I render the text in html and open it in lynx or such and its amazingly easy to read. Borrowing on this principle you’ll find the few ebook readers render their fonts as a clerar black on grey or white, and at high contrast settings. These might be worth a see if one is heavily into e-texts. Whew, that was a long ramble :) But this is a topic close to my heart, as I have an entire library, books, comics, et al. as documents on the computer.
Ashwin Prabhu 22 Feb 2008 12:00 pm: Try http://www.wowio.com/index.asp . It allows upto 3 ebooks to be downloaded a day. For some strange reason, this site works only on non-Indian IPs.
joseph 22 Feb 2008 12:00 pm: Amazing that you are able to hold up a laptop to read on a train and not have eyebrows raised. Guess the English are rather blase about stuff on the tube.
Chittaranjan 22 Feb 2008 12:00 pm: I could never stick to the habit of reading on my Laptop. I get tired/cranky/irritable after the first few pages itself! I tried the ‘read aloud’ option in Adobe Reader but that is worse than self-reading.
edgar dantas 22 Feb 2008 12:00 pm: hey nice blog and nice post i really appreciate it with regards edgar dantas www.gadgetworld.co.in
Aman Patel 29 Aug 2008 8:14 pm: Nice post. I like your post. Happy Posting…
Hari K T 3 Jan 2009 7:26 am: Yes, this is a good idea . Back pain its one of the problems that all professionals facing ….. :)
Kavitha 19 May 2009 1:15 am: Hi, Could you pls let me know if it is possible to rotate a website in the manner you have shown above? I read a lot of books online and it will be very helpful if you let me know the keys to do it; at work i have sometimes accidently done it but i’m not able to remember which key i had struck. Thanks!
krishnan 5 Jan 2010 7:02 pm: Yes..It is possible , there is a free tool called irotate…and another one called sakasa mouse tool… u\can tilt the screen and rotate the mouse in sync with this..as well!!!!
Andrew 6 Sep 2010 5:49 pm: I’ve been doing this for years also. The Ipad is my ultimate goal but any laptop is great. I’ve had some hardcover books that were as heavy as laptops and that was just ONE book. A laptop can hold a thousand books/comics. Its a portable library that outweighs (no pun intended) all the negatives, if any.
Anirban Mukherjee 24 Jun 2010 5:06 pm: In order to rotate the screen press CTRL+ALT+right arrow or CTRL+ALT+left arrow. Ref. http://getahead.rediff.com/slide-show/2010/mar/02/slide-show-1-specials-all-about-ebook-readers.htm#contentTop
colin 28 Jul 2010 6:47 am: you should never turn your latop on it’s side like that, the hardware really doesn’t like that
Lynn 21 Oct 2010 3:23 am: I am new at this. I just started looking around to see if I could get books on my laptop, so this is a good discussion. I still don’t know much, but will keep reading what you all write and see if I can figure it out. Thanks to all who participate in helping the “new kid.”
Prashant 31 Jan 2011 7:39 am: Reading on netbook is better than laptop ,but the problem with these tools is that it hits one self’s personality as eyes go red(straining over an hour) with stoop, staggering walk at worse ,so ebooks may not be better at this point but the other face of the coin is that if this tool is used for the very purpose of learning it does not hamper us rather wasting time on internet, porn,news reading(can be done with news paper),surfing unnecessarily can be lethal at its counterpart, so i am neutral to this fact that reading on laptop is good for ourselves.
BKD 9 Jun 2012 11:04 am: Amazing! I struggled for days before i came across this. The only change is that I change my desktop orientation altogether. This allows me to not only read, but to annotate my PDFs too (highlight, comment, notes and stuff) using my mouse. As keyboard is obviously difficult to use when laptop is lying like this, I use on screen keyboard for petty stuff. Using Ubuntu 12.04. Works like a charm! Thanks !

Transparent laptop screen

Wed, 30 Mar 2005 12:00:00 +0000

Transparent laptop screens. Quite clever, actually. via Dhar

Comments

S Anand 30 Mar 2005 6:15 am: More transparent screens at Flickr

Internet on flights

Mon, 09 Dec 2002 12:00:00 +0000

Insight from a NY Times article on how the Internet can be accessed from flights: the reason you shouldn’t use a laptop on a flight during take-off and landing is not because of electrical interference; it is that the laptop could be a dangerous loose flying object in case of turbulence. Now, that makes more sense.

Not such a good idea

Sun, 23 Jun 2002 12:00:00 +0000

Notebook computers are not such a good idea after all.