Pi on the Side.

So I bought a Raspberry Pi. Just in the unlikely case you have not heard of this credit card sized Linux computer at the incredible $35 price-point you can read all about it on the Wikipedia entry. And since I will try to write down my experiences I decided to create a separate blog for it.:

I Spy My Pi

(which does not really mean anything, it just sounds nice..)

Back to The Valley. (in 8-bit country)

August 3, 1977 was the public introduction of the TRS-80 home computer. Which is as I write this is more than 35 years ago. The most recent episode of this developers life ('Dinosaurs') brought back memories to this first real computer I could get my hands on. The setup as shown here is exactly what my father bought about thirty years ago. A black and white 12" monitor (16 lines of 64 characters), a 1.77 MHz processor and 16KB of RAM. Program storage on a cassette tape recorder which meant loading a decent game would often take 10 minutes or more. And to me it was magic. From the very first time I switched it on and saw the READY> prompt I was hooked. To programming. I remember it started with the sample from the owners manual. No, not the obligatory 'hello world' but a Celsius to Fahrenheit conversion program. And after completing all samples I did a very simple Space Shooter. Written all in Level 1 basic, using all ASCII characters, so you can probably imagine it did not exactly look like "Skyrim' or 'Modern Warfare'...
Then one day I bought the latest edition of 'computing today', mainly because of the cover. Today games actually look like that, but back then those images could only exist in your imagination.

 And programming a real adventure game, with "goblins', 'wizards' and ''barbarians' sounded like an extraordinary challenge.
So I spent weeks typing the the listings and converting the code from the original Commodere PET basic until I had a real working game which eventually I hardly ever played. It showed me that for me the real fun was in the programming itself, which it has been ever since.
The program as I written it has been long lost. It was stored on a cassette which we probably gave away when we sold the TRS-80, and I did not have a printer then to make a hard-copy. But guess what: it's on the internet. It took some searching but finally I found an article by Paul Robson and this one by Tony Smith on reghardware.com .
Both more or less describe the same experience, and on the site of Frank Fraser there is even a full scan of the listings. Looking at the scans I suddenly realized that I probably still had a copy of the magazine somewhere and so I did. The scans shown here all come from my personal copy. Actually I thought my copy would be 'cleaner' than Franks scans. But memory tricked me and the weeks of intensive use also left their marks on the pages, as can be seen in the section where the different graphics are explained.

For a moment I considered trying to rewrite the program using a TRS-80 Emulator. Just to see if I could re-live the excitement of that time. Probably not. And after playing the BBC version (which is included in the zip-file that contains the scans) I found this type of game is still not my favourite.

Lets face it, the most enjoyable part of recovering an old computer magazine are reading the ads. Like this one on the rear. 'Fully expandable to 32K of user RAM' and a 'Full set of upper and lower-case characters'. What else would you ever need ?

Holy Cow, I Wrote An App !

(Of course the title refers to Raymond Chens post about the only book he ever wrote..)

In 15 lines of code... And it's an unique one. And it does something that is probably useful to (a maximum of) 10 people in the whole world.
Last year I bought an Archos 7HT Android Tablet. It was one of the cheapest tablets then and this means it has limited capabilities. One of the limitations is that it does not have an option to switch to portrait mode. It has no tilt sensor and there is no special button or built-in option for it. So if you display a webpage it is always in landscape mode which is sometimes inconvenient. Like when I want to view the a popular site that shows when and where it will rain in the coming hours. As I live in a small country, it could fit in one screen IF displayed in portrait mode.
So I decided to look into the possibility to force the standard browser to start in portrait mode, which is (as far as I'm aware) not possible. Then I found a reference to the 'WebView' ("A View that displays web pages") component and guessed that this could be a way to solve the problem.  And it is. I just created a standard Android application, followed the instructions on the WebView reference page to place the component on the main page, and forced the view to portrait using the appropriate function (that I found on StackOverflow).. That's all. Here is the code:

package CScope.Buienradar;

import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.webkit.WebView;

public class BuienRadarActivity extends Activity {
    /** Called when the activity is first created. */
     WebView mWebView;
     Button myButton;
     @Override
     public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mWebView = (WebView) findViewById(R.id.webview);
        mWebView.getSettings().setJavaScriptEnabled(true);
        mWebView.loadUrl("http://buienradar.mobi");
           setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    }
    }

The blue lines are actually the only code written by me, all the rest was generated by the Eclipse 'New Project' wizard. And when you press Run or Build a complete installation package is created in the 'bin' folder of the project that can be copied to the device.  Let's face it, this is almost too simple.... So that even left me time to create a fancy icon.


(And if you by coincidence are one of these 10 people: you can download it it from here: BuienRadar,apk)

3-D Television or television for 2 ?

3D Television is hot. To talk about...
Despite getting the impression from magazines, exhibitions and showcases that 3-D  is coming fast to all of us, I have not actually seen one in the shops. And certainly I do not know anybody who has one. And most reviews I hear or see all mention the fact that it is 'just not really there'. The 3-D images do not look 'real', and most televisions suffer from 'shading' or contrast problems. And the fact that everybody has to wear 'electric sunglasses' probably does not help either.
Anyway, technology will improve fast and we'll probably see some decent screens at a reasonable price level by the end of next year. What I have not seen yet is a different application that might be more interesting to a lot of people: dual view. 3-D televisions repetitively show two different images. And the 'shutter glasses' just cover one eye at the time in so each eye sees only a slightly different image, thus creating the 3-D effect. But what if you fed the TV with two completely different programs and have the shutters cover both eyes at the time ? This way your wife can watch episode19745 of  'As the World Turns' while you are watching tonight's major league football match !.
(Yeah, I know you would both have to wear a headset as well, but I suppose that could be integrated in the glasses.)

In Touch with the Tablet (or why I DO like the Archos 7 )

Two years ago I was one of the first to buy a 'small form factor computer', the EeePc 4G. Almost hard to believe nowadays with the omnipresent Netbook, it was the ultimate gadget at that time. The idea that you could have a fully functional PC with a solid state disk, a 7" screen and keyboard for only €250,- was just too exciting. However I've been struggling with the so-called 'use-case' ever since. To be honest, the keyboard is just too small and too flaky for decent typing, the screen is too small for real work and even playing YouTube videos is almost too much for it's little processor.

Today the Tablet PC is what the Netbook was then. Tablets in all shapes and sizes are already released faster than you can read their reviews and the expectation is that the real flood will start in second half of 2010. Combined with the explosion of smartphones, touch based UI's are suddenly everywhere.

Of course there is no doubt that the iPad is the ultimate touch tablet. But I have this aversion towards computers that you cannot program yourself.And I don't like paying €100,- bonus just for the name, so there is a chance I will never own one. So along comes the cheap Archos 7 Home tablet. An Android based 7" touch tablet with 2 Gig internal memory and about 10000 times the processing power required to send a rocket to the moon.. All that for just €150,-! Actually there are a bunch of (even cheaper) Chinese tablets on the market like the iRobot / aPad, but they look cheap even on the promo-movies and most reviewers admit they are probably a bit too cheap. And of course there are 100 different tablets 'to be released soon/next quarter/beginning next year'...At least Archos is a well known French company with a solid reputation for building good media players and their model is available now !.So I guessed it could never be that bad and at least you get what is specified.

And I'm not disappointed.

First: it looks great. It has got a solid 'brushed aluminium'-look on the base and a nice black edge. The formfactor is really good. It's really comfortable to hold with both hands while scrolling with your thumbs.

iPaq 3800 - Palm Vx - Back to the future of touch...

The screen is pretty good too. At 800x480 resolution is just big enough to comfortably view websites without much scrolling. The colours are bright, the image is crisp and the brightness is good enough even when it's used outside (provided it is not too sunny). And the resistive touchscreen is.. ehm.. well...OK. This touchscreen is the usually the core of all negative reviews of the '7'. But I'm used to my Palm Vx, iPaq PDA and Garmin Nüvi GPS so resistive touchscreens come natural to me. It's what you're used to. And I'm sure if the iPhone was your first touch experience you'll be disappointed with the Archos.
But I am not.
Although I'm not really sure whether it is the 'touch tablet experience' itself or the device I like. I've been using it for a few weeks now and I find myself regularly checking e-mail, reading websites, e-books and even comics. When fully charged it can be on standby for two days so I can just pick it up, touch it and check the latest news, local weather or just read some Dilbert strips. And I can even program it ! Using the Android scripting layer you can write Ruby, Perl or Python scripts, right on the device. Not that I will probably ever use it to write any productive code but it's just the idea that you can do it makes me feel at ease.
Anyway, if you're looking for a reasonably priced 'first try' tablet and you're not spoiled already by any Apple product it's worth checking out.

UPDATE(27/10/2010): Much to my surprise Archos recently released a firmware upgrade for the 7 HT . And somehow they managed to really improve the touchscreen response so it is actually pretty good now !

Too late for Windows Phone 7

Things change. Some things change fast. Computer industry changes faster and mobile phone trends change at light-speed or beyond.
Just a few months ago I was excited to learn about the the upcoming Windows Phone 7. The demo's are awesome and it really looks like Microsoft is serious about building a real phone OS. They actually gave up on backwards compatibility with the Windows Mobile OS (codename Dinosaur..) and chose a combination of the Silverlight and XNA. Technologies that are both targeted at rich content and game development. And they are giving the development tools away for free. Anyone can start building apps using the free Visual Studio Express . All very exciting.

But..

The first Phone 7 devices will not hit the market before September 2010..
And that is much too late. Googles Android has just hit release 2.2, making it an almost mature phone OS, and they will probably have release 3 by the time the first Windows phones are released. Development tools for Android are also for free, and maybe not as slick as Visual studio, Eclipse with the Android SDK comes pretty near. And it definitely beats the almost arcane development experience for the iPhone. But what is most important: the phones are already there. Some of the coolest phones of this moment (like the HTC Legend or Samsung Galaxy) run Android, and it is rumoured that the sales of Android based phones has just recently surpassed those of the iPhone. Which again makes clear how fast things are moving in mobile land. With the iPhone, Blackberry and Android firmly established when Windows Phone 7 arrives I give Microsoft very little chance of succeeding.

 And did I mention thinks change fast ? I just found that Paul Graham (who is supposed to know) mentioned in his essay of November last year:


The only credible contender [to the iPhone]  is Android. But Android is an orphan; Google doesn't really care about it, not the way Apple cares about the iPhone.


I don't think that is true anymore...

Google link soup: Back to WEB 0.1

Only recently I took a look at the Google reader / My Stuff page which is part of the iGoogle portal. And boy, is this a mess... (Screen-shot on the right->)
Fifteen Underlined links, one that is an image (the 'Google Reader' image and one in small print light blue at the bottom left.)
Seven buttons in two different heights, all different widths, one with an icon, one greyed and one button that is actually a dropdown box and a search box. Eight clickable menu items of which two have an icon in front of the text, two have it after the text, three have no icon and one is printed bold.And still they did not have enough ways to leave this page so there is a 'More' menu of which the last entry is the option 'Even More..'
Google apps on the web is a horrible UI nightmare. I really don't understand how they ever expect to take over the desktop from a browser centric OS if they continue on this path. Let's face it: it is already extremely hard to create serious office applications that run in the browser and meet even the minimum level of usability. I even dare to say it is impossible using the current state of the browser technology. I currently use a browser app myself on a daily basis and even though it's very well thought out, does everything we need and has a slick user interface, it makes me itch every time I use it. Every day I try at least ten times to move, copy or delete a file by clicking my right mouse button. Which brings up the browser context menu...
And when I move through the explorer-like files list it annoys me that every step through the tree just takes anything between two and ten seconds. So why did we spend the last decade in doubling computer performance every year to get faster interaction if we are now giving this all away because everything must run in the browser ?

Name your Number : Great Joy !

Recently I stumbled on site named WikiDump that loosely archives interesting but deleted items from Wikipedia. There I found an an entry on the 'Zuckerman number' that intrigued me.

A Zuckerman number is an integer that is divisible by the product of its digits in a given number base. All integers between 1 and the base number are Zuckerman numbers. No integer with a zero as one or more of its digits in base b can be a Zuckerman number in that base. In base 10, the first few Zuckerman numbers with more than one digit are 11, 12, 15, 24, 36, 111, 112, 115, 128, 132, 135, 144, 175, 212, 216, 224, 312, 315, 384.

And here is the Wikipedia entry that discusses the deletion.
What I considered strange about this is that the definition of this 'special numbers' seems quite valid. Although the usefulness of this (other than making it a programming exercise) seems arbitrary, I see no reason why mr. Zuckerman does not deserve his small area of fame for discovering it. So I decided to dig deeper...
The definition can also be found on PlanetMath, which claims to reference 'J. J. Tattersall, Elementary number theory in nine chapters, p. 86. Cambridge: Cambridge University Press (2005)'
Now this book is by no means a fake or in any way humorous collection of real mathematics. I briefly went over it and checked some facts and biographies, and it all seems pretty legit. The tricky part is that on 'Google Books' the referenced page 86 is not present. Mr Zuckerman himself though is present on several other pages, proving that he is in fact a significant mathematician. In fact he was co-author of 'An Introduction to the Theory of Numbers' (By Niven, Zuckerman and Montgomery) which is a book that is often referred to in math studies.
But when we search for the other author, Ivan Niven, we find that there is actually something called a 'Nivenmorphic' number. And the definition for this is ' an integer that is divisible by the sum of its digits when written in that base'. Which by now sounds familiar. To add a little confusion though, the official name for this seems to be a 'Harshad number'. And Harshad means 'great joy' in Sanskrit. So who said mathematics was no fun...?

Edit 2020: This has been on my blog quite some time, and only now I see my mistake: Zuckerman numbers are divisible by the PRODUCT, and Harshad numbers by the SUM of their digits ! So they are actually completely different. And if you google the 'Zuckerman Number' you will find it is well represented throughout the internet.

Went over the world.

Some time ago I bought a AC/DC power adapter for my notebook. It's an amazing little device that takes anything from 12 Volt DC to or 110-240 VAC as input and supplies anything from 12 to 24 VDC to a laptop. It came complete with a 12 V car plug, a mains lead and a set of adapter plugs for only 20 Euro. It was made in the People's Republic of China, where the percentage of people that speak English is probably negligible. But the packing-designers assume that there should be some English on the box to give it something like a professional look.
So here it is:

'In My Mind Do Not Forget You Even'
'Went Over The World'

(note that the last sentence is technically correct...)

It looks like they brought in some random phrases. Just like European companies sometimes copied Chinese symbols from the window of the nearest Chinese restaurant to give their products an oriental look. But where do you find texts like this? Or is this an image of a typical 'European Pub' in Peking...

Multi-Multi Tasking

Multi tasking is not my thing. Apart maybe from listening to music while ironing, any other combination just does not work for me. When I'm doing 'serious' work (like writing software, design electronics, create a report, just anything that requires a significant level of concentration) it takes a while to get started. And any interruption, no matter how short, will cause my mind to reset and start all over. It's even worse when there are two or more tasks at hand that have equal priority. Anything (e-mail, phone, colleague bringing coffee..) can trigger me to shift my attention from one to the other and if this happens often enough none of the tasks get finished at all. And I'm not sure having many arms ( like this Indian god) would help. It's in the mind.
Well, a lengthy intro to the real reason for this post. Someone pointed me to this video on YouTube. How nice it would be if you could replace Guitar Hero with Visual Studio and the Rubiks cube with some kitchen gear so you could prepare fresh pizza while you are coding...

Criss Cross Platforming Speedup

I've written a lot so far about my fascination for cross platform development. Unfortunately my time is limited so I do not spend as much time on it as I would like. And every time I find a little time to pick it up I find to my surprise that others are proceeding down the multi platform road at a much larger pace. Like the Mono team, lead by the the brilliant Miguel de Icaza . Check out StackOverflow podcast #61 to find out he's also a amusing speaker (which is a well known rarity among good programmers...)

Here he also announces the introduction of Mono tools for Visual Studio. This will allow simultaneous development on Linux an Windows. And since Mono is also working towards iPhone application development it is getting really interesting. I believe that we are now slowly working towards the real future of software development. It will not be long before it is relatively easy to create applications that run on Windows, Windows Mobile, Mac, Linux and the iPhone. Something I would not have thought possible two years ago.

Hardware vendors should NOT make software

Hardware and software manufacturing are two different professions. Really. Believe me. Trust me. And if your good at one of these stay away from the other (unless you are Apple.)

The best example is a piece of software that is made by one of the largest and most successful manufacturer of everyday hardware: The 'Nokia PC Suite'.
It is definitely the worst piece of software I have used in years. First it's the only Windows program I've ever seen that somehow tries to render it's own fonts. Look at the image on the right, showing the barely readable menu. And believe me: this image is not compressed or manipulated...
Nice detail is that the Settings menu first item is 'Settings..' which almost sounds like there is way to change Settings like font or fontsize. Well, it's not. You can select where you want your popup when your phone is ringing or if you want to send 'Diagnostic information'. Exactly the two things I could care less. I want to switch off automatic updates ! Thes updates come on regular basis and you get this annoying balloontip warning every time you switch your PC on, so in the end you just have to agree.
Upgrading however has a totally different meaning to Nokia then for example Microsoft. A Nokia 'Upgrade' means downloading a complete 35 MB installation file which leads you through the complete installation every time like it was the first time. It decompresses itself to a giant 290 Megabytes and you cannot leave it in the background since you have to agree to the license, answer the standard installation questions and click to finish. Finally it even wants you to RESTART your computer ! The only funny thing about this is that this is the only window in the suite that uses a clearly readable font.
So the question that really bothers me is 'Why ?' Why can't a company like Nokia, known for it's high level of engineering produce a decent piece of software to support over a billion phones ?
I suppose they just have it developed by trainees that dropped out of the hardware engineering course...

I'm not alone in .NET Cross Platform land

So I'm not the only one to work on cross platform .NET applocations (how come I'm not really surprised..?) The Banshee Project is a cross-platform multi media player based on .NET and Mono. Though my only experience with the Banshee player is not positive ( It could not play MP3 without hickups on my EEEPC ) it is a great project to show the power of cross platform development. And I'm sure one of these 95 developeres working on it will eventually solve the EEEPC problem.

Banshee creator Aaron Bockover talks about it in a recent Hanselminutes Podcast. Both the show and the shownotes mention that it will run on Windows, but I actually could not find it on the Banshee homepage. On his Blog he mentions working on it, (despite of his aversion to Windows programming) but the status of it is not really obvious.

Fun with acoustics

Usually it's about computing, but this this XKDC Comic suddenly comes very close to my professional interests. Though not for marking sharks I'm currently part of a team that develops an intelligent acoustic tag for monitoring instruments that are on the seafloor.

As far as I know it's the only really trace of humor I've ever found regarding underwater acoustics...

And we call it 'Low cost small notebook PC' !

So Microsoft wants to rename the 'Netbook' to 'Low cost small notebook PC'. Great idea. (maybe also since Netbook is actually a copyrighted trademark from Psion..) I think everybody will be happy that this clumsy word will now be replaced by a much more descriptive term ;-) Maybe an abbreviated version ('LoCSNoP') could be used to make this new initiative a huge success like the previous smash-hit 'UMPC'

But why did they not take the opportunity when introducing Windows 7 to rename it to 'Mid priced GUI based operating system for personal computers and laptops, version 7' ?

Blog or advertorial ?

Being a long time fan of Jeff Atwoods Coding Horror I recently found myself annoyed for the very first time. Not by the content of his writing but by the way he uses links to books. Actually he discusses books a lot, and in general each book title is also a link. But it's a link to Amazon so I can immediately BUY the book. But that is seldom what I want. Unless the blog contains a thorough review of the book itself so the only thing left to do is read it yourself. But if you just mention a phrase and the title the link should lead to the book or authors website so you can find some additional info.

I know advertising is the main (only) source of income for professional bloggers but you should be aware that your are walking a thin line when balancing between credibility and commercial benefits.

And yes, that's the reason why there are no ads on this blog ;-)

User friendly, or friendly users ?

UI development has been a source for discussion. Books have been written, entire blogs are dedicated to it and when you start reading and digging deeper you'll just get to a point where you will become completely stuck. You'll think weeks about every single menu item, background colour gradient angle and button placement.
Yet I've written an application that has a UI that would not even pass the basic test for usability and I never had a single complaint about the interface! The menu structure is not really logical nor standard, dialog boxes for similar functions vary widely in appearance and their buttons are placed almost at random. And when you click 'Help' it just opens a .pdf document that contains only the very basic instructions.
All this happened because it started as an 'internal use only' application and grew by demand through the years. Functionality was added on the fly if someone required it to get a specific job done and often I just 'plugged in' a windows form from a different app just because that already contained most of the functionality of what I needed at that time.
And then suddenly the application was 'promoted' to end user software and supplied with an expensive piece of hardware and used by a slowly expanding group of people around the world. So on regular intervals I get feedback and requests for change but it's always about the functionality. A calculation is found incorrect, export functions should export more values, graphs should show more details and so forth. Never ever did somebody complain about the arcane data editing function, the strange menu structure or the crippled help.
The users are certainly not computer specialists. They are people whose main job is just to do measurements. They just need that software as an additional tool in a similar way they need a four wheel drive, rubber boots and ropes. And it seems they don't really care how it works, as long as it gets the work done.
"So I have to press the left mouse button three times while holding control, shift and F4 to get a printout ? Al right. I'll write it down."
And they will always do it like that. And if they have to instruct their new colleague it will give them a good feeling that they know this awkward combination by heart. My feeling is that they treat it like any other professional tool. You have to learn how to master it and it becomes part of your professional skills. I suppose that is the reason why Linux adepts stay enthusiastic about their operating system, even though they have to get to the command line and type their cryptic commands for anything but the most trivial tasks.
"So you can operate the LHC ? Big deal, I know how to get connected to my bluetooth phone from my Linux powered laptop !"
(Don't mail me about this last remark. I have no idea..;-)

Finally: One language, three worlds.

Eureka. At last. With the release of the System.Windows.Forms assembly for Mono a dream comes true. Well, this sounds a little over the top but it felt like that the first time I got my 'SimpleTerm' application running on Ubuntu. SimpleTerm is C# application for serial port (RS232) communication that I originally created for the PocketPC using SharpDevelop. By using only CLR functions that are available in the Compact Framework I could build an application that runs on a PDA and a desktop, unchanged!. So it was exactly the same bytecode on both platforms. Now this does not work on the Mono platform (although there seems to be a way to patch the bytecode itself) but after I imported the project into MonoDevelop and just compiled it, it actually worked ! Which could be considered as a breakthrough merely for the fact that it supports serial communication !. So it's not just a 'Hello World window' with an OK button but its a real application that even supports the most underappreciated form of digital communication. And I say 'underappreciated' because the RS232 specification was established in 1969 and it has been the main form of communication between computers for over 35 years. But it is only since the release of System.IO.Serialport in version 2 of the CLR that serial communication is really supported out of the box in a mainstream development framework. I know this is not an issue for most people, but if you are working with instruments and microcontrollers whose only means of communication is still plain RS232 it is a real revelation.
The image shown here is a combination of three screenshots, one of a PocketPC emulator, one from an Ubuntu system running within a virtual machine and one from a 'standard' Windows XP computer. The text in the main window of the application shows the result of a call to 'Environment.OSVersion' which indeed reports the operating system and version on all three systems.

Creative AdWords

Usually I feel the 'intelligence' of Google is impressive. Almost every search I do leads me to the right pages within the first two or three results. And the ads shown on the right of the search pages are also often remarkably relevant. That's why the WTF page shown here really surprised me. (Yes, you hae to click on it to see the details). I saved it as a screendump, since it is unlikely that you would get the same results if you visited the original article now.
On the other hand, the WTF site is definitely a site for real nerds, so the first ad ('How To Pick Up Girls ?') might be in the right place after all.
For those of you that do not master the Dutch language: ad 3 and 5 both lead to shops that sell underwear. Clearly AdWords got mislead by the multiple occurrence of the word 'String' in the source code Which is strange if you realise that Google programmers are probably among the 0.001% of people whose first association to this word is 'string of characters'.

Is a €550,- Netbook still a Netbook?

With the introduction of the ASUS PC S101 you start wondering what the definition of a Netbook is. The S101 has a larger screen and a bigger keyboard and this of course is reflected in the price of approximately €550,-. Well, maybe I see it wrong, but for €550,- I can already choose from a myriad of different 'normal' laptops that already have a larger screen and keyboard. And way more storage capacity than the internal 32 GB SSD of the s101.
ZDNet defines a Netbook as 'A subnotebook computer that costs less than US$400 and incorporates an Intel Atom microprocessor'.
I would add to that the following:
- Weight less than 1.5 kg
- Runs from batteries for at least 4 hours
- Wifi
- Solid state disk
- Maximum 10 Inch screen

That's a netbook, or else it should just be referred to as portable computer.