myDimension

Tracking mouse position on your vertical, annotatable, jqPlot line chart

2012-10-02T04:03:00.000+05:30

In my last post i showed you how to create a dynamically updating line chart using jqPlot library and how make the chart flip its orientation. This time i wanted to track the mouse position on the chart so i can put some annotations to the chart. It was possible to display annotations on the chart using the pointLabels plugin and some CSS tricks as the previous one. All i had to do was to add the annotations to the data array and make the pointLabels plugin display the content in the 3rd index of the data array as the point label.

   1: pointLabels: {

   2:     show: true,

   3:     seriesLabelIndex: 2

   4: }

This was working fine when the chart was in horizontal position. However when the chart was in vertical position the position of the mouse was not detected and as a result it was not possible to know which position in the chart should be annotated. I tried different methods, but was unable to find a solution. So i had to change the code in the library it self. I had to change the jquery.jqplot.js file, which is the core library file in order to achieve the result i expected. Here's what i did. First i had to insert the following code into the jqPlot class of the jquery.jqplot.js file.

   1: function jqPlot() {

   2:     //add the following code segment

   3:     var verticallyOriented = false;

   4:     this.setVertical = function(state){

   5:         verticallyOriented = state;

   6:     }

   7:     //don't change other code that isn't mentioned here

8:

   9:     //now you have to change the logic in the getEventPosition function

  10:     //to make sure the new orientation is detected

  11:     function getEventPosition(ev) {

  12:         //change the line starting with var gridPos = ...

  13:         //to the following code segment

  14:         //depending on the orientation the event position calculating algorithm is changed

  15:         if(verticallyOriented){

  16:             var gridPos = {x:ev.pageY - go.top , y:plot.eventCanvas._elem.height() - ev.pageX + go.left};

  17:         } else {

  18:             var gridPos = {x:ev.pageX - go.left, y:ev.pageY - go.top};

  19:         }

  20:         //no change to other code is needed

  21:     }

  22: }

Then when the chart was flipped i could simply call the setVertical() method so the library detects that it has been flipped.

   1: $("#flipbutton").click(function() {

   2:     if ($('#chart1').hasClass('vertical')) {

   3:         $("#chart1").removeClass("vertical");

   4:         plot1.setVertical(false);

   5:     } else {

   6:         $("#chart1").addClass("vertical");

   7:         plot1.setVertical(true);

   8:     }

   9:     plot1.replot();

  10: });

You can find a working example of the above work here. You can click on a point on the chart to add an annotation to that point. (try it out in both orientations)

You can download/view the gist of the changed jqPlot core library file here.

If you have any problems/questions regarding this, please let me know in the comments.

Simple dynamically updating line chart generation using jqPlot

2012-08-30T15:39:00.000+05:30

jqPlot is a nice plotting plugin for the jQuery javascript framework. While i was working i just had to create a simple example to see how the library works. So i created this dynamically updating chart which plots random data in 5s intervals. The orientation of the graph can also be flipped. This was achieved from a simple rotation of the div element containing the chart using CSS rules, and rotating the axis labels correspondingly.

This is just a small code, but there was no example to see how this feature works. If any of you need to see how to implement a dynamically updating, vertical/horizontal chart using jqPlot you can have a look at this.

View the next step of this tutorial: Tracking mouse position on your vertical, annotatable, jqPlot line chart

Facebook offers free anti-virus software

2012-04-28T08:59:00.001+05:30

Hi all, I am here to give you all a quick tip. Our beloved image sharing site, Facebook, has launched a service to provide Security suites, virus guards and internet security suites, for free. Actually the products have a 6 months trial period with full functionality. The whole purpose of this free give-away is to enforce the Facebook users against malware, viruses, worms and all those black stuff.

The steps are simple. Go to this page, https://www.facebook.com/security and select The AV market place.

Then you will get the page with details about the security suites provided by different vendors such as McAfee, Microsoft, etc.

Select the product you want to install to your computer and follow the instructions. You may have to like the Facebook page of the vendor in the process. But that's not much of a trouble when we consider the type of things we put a like on Facebook. ;)

After you download, install the product and enjoy 6 months of security from a fully activated product.

That's it for this quick tip. I'm out. Stay safe people, Internet is getting scary. =O

PS: If you like my blog don't forget to subscribe for more, just move your mouse to the right side of the screen and a pretty side bar will appear, select "Followers" and click follow. Cheers! =)

Google Project Glass

2012-04-08T12:01:00.003+05:30

"We believe technology should work for you — to be there when you need it and get out of your way when you don't." says Google in their latest awesome video, which tells a tale in the future, and hopefully it's the near future. The video is about a new project by Google, which is Google Project Glass. First watch this video, if you haven't looked at it already. It has been there for few days now.

I'm sure anyone who enjoys technology, at least when it's trying to ease our work, would appreciate the potential of this project. With the help of other Google's new projects such as Google Indoor maps and constantly improving broadband technologies such as 4G this will be a product that may not be that far from us. In fact according to this post by Engadget, it seems Google has already implemented few prototypes.

The product will have its ups and downs, nevertheless we have to admit that this is what the future holds for us. +1 at Google for speeding up things. It seems that Google has been involved in lots of innovations-slash-crazyideas lately.

Some help for your interview - My check-list

2012-03-26T23:26:00.000+05:30

Recently, due to the upcoming internship/training period here at the University, everyone is going for interviews, including my self. So before going to my interview i made a check-list to prepare my self for the interview. I decided to give you guys my check-list and what i referred so it'll save you some time and will be of some help to you in the end.

First of all, this is the set of list that i thought i should have some understanding before going for an interview for a trainee software engineer.

Object Oriented Programming concepts

I think this is a must know. I referred to this link, it contains so much stuff.

http://www.codeproject.com/Articles/22769/Introduction-to-Object-Oriented-Programming-Concept

UML - You should also know a bit about this. The above link contain some details about UML concepts. You can also follow these,

UML - http://www.uml-diagrams.org/
UML class diagrams - http://www.uml-diagrams.org/class-diagrams-overview.html
UML use case diagrams - http://www.uml-diagrams.org/use-case-diagrams.html

Some companies ask heavily about the Java API (if the company you're applying has a reputation as such you should have some understanding about Java)

Design patterns

This is also a must-know. You can follow any of these links.

Data structures and Algorithms

It is better to have an understanding of some basic algorithms such as sorting algorithms such as bubble sort . It is always better to have some understanding on how these algorithms operate. But not every company asks these.

Operating System concepts

http://programmerinterview.com/index.php/operating-systems/introduction

Software engineering concepts

Architectures (two-tier, three-tier, multi-tier) - http://www.codeproject.com/Articles/22769/Introduction-to-Object-Oriented-Programming-Concept#two-tier
Agile development - eg: Scrum in five minutes - http://www.scribd.com/doc/334808/Scrum-in-5-minutes
SOAP - knowing the content on this page should be enough for you to get some understanding. http://www.w3schools.com/soap/soap_intro.asp

Database management concepts

ER diagrams - http://www.scribd.com/doc/7122945/ER-Diagram
Database normalization - http://databases.about.com/od/specificproducts/a/normalization.htm
ACID - where else to go other than the good 'ol wikipedia - http://en.wikipedia.org/wiki/ACID#Atomicity
SQL commands - http://www.sqltutorial.org/sql-cheat-sheet.aspx

Good idea about the recent projects you did

Nobody else know about these better than you do.

Some idea about the recent developments in industry and technology

It's always good to be interested about the field you are going to work.

You should also read this as well. This site covers lots of technical aspects.

http://www.programmerinterview.com/

Please note that you must not go through all the stuff here and it is not a must that you should know everything, there's always enough time to learn if you're open to the idea.

Above all here are some important tips i got from people who actually know these stuff.

"Not too early, not too late", be there at least and at most 15 mins early - Rushing up to the place with a body full of sweat won't help much when you try to concentrate on much important factors
have a positive attitude
always smile
be confident
Respect the interviewer
do NOT lie - if you don't know something, don't fool around, just say that you don't know it, because there's a very high probability that the interviewer has a good knowledge on that topic.
be practical
And last but not least, answer the phone calls from unknown numbers, at least till you get selected.

I am no expert in any of these stuff as i have only gone for one interview. But i'm sure these will help you to polish up yourself. And if you are confident in yourself you'll definitely get selected.

Hope this article is helpful to you all. Please leave a comment with suggestions/corrections on anything i have put here, so it'll help anyone else reading this.

If you are extremely lucky you'll just get to sign the contract at the day of interview, and in some cases you may be asked of the game you are playing these days throughout the interview.

So all the best for your interview. Most probably it would be tomorrow, that's why you are searching for some tips today. ;) So all the best again. And sleep early today.

PS: Thank you Lakmal ayya for the additional tip.

Roll back to text buttons in your Gmail

2012-03-19T23:02:00.001+05:30

I think although most of us enjoy the new and more dynamic view of the gmail, the buttons on top which are viewed as icons are not so intuitive to many users.

But fear-not! Google has introduced the option to roll back to the good-old intuitive text buttons. Just go to the settings and scroll down until you find "Button labels" option. I think you will be able to figure out what to do next. ;)

After you save the changes, the new interface will look like this.

A small help from me. I'm out! Cheers!

Android How to | Display a gif image in an ImageView widget

2012-02-10T00:12:00.001+05:30

While I was working on my 3rd year programming project which happens to be an android application (I’ll tell more details to you guys about the project in later posts that are to follow), I wanted to display an image on the screen acquired from an external web service. The problem with the image was although the image was not-animated, it was in gif format. I tried various methods to get it displayed in the application, searched on those deep corners of the internet (yeah, I’m talking about those places ) but couldn’t find a successful solution. After few hours of trying I succeeded. And it was a simple solution that worked. After a long pause between my blog posts, I thought of sharing this small tip with you guys.

Here’s what I first did. My web service uses REST protocol. I used HttpClient in Java and HttpGet commands to acquire the image. Then I passed the input stream of the HttpResponse to a BitmapFactory to decode the gif image into a bitmap. Then my method simply returned the Bitmap to the application UI. Here’s the code for that task.

   1: public Bitmap getBitmap(String url) {    //pass the complete URL of the web service query

   2:     Bitmap bmp = null;

   3:     try {

   4:         HttpClient client = new DefaultHttpClient();

   5:         URI imageURI = new URI(url);

   6:         HttpGet req = new HttpGet();

   7:         req.setURI(imageURI);

   8:         HttpResponse response = client.execute(req);

   9:         bmp = BitmapFactory.decodeStream(response.getEntity().getContent());    //BitmapFactory decodes the InputStream of the HttpResponse

  10:     } catch (URISyntaxException e) {        //catch those exceptions

  11:         Log.e("ERROR",e.getMessage());

  12:     } catch (ClientProtocolException e) {

  13:         Log.e("ERROR",e.getMessage());

  14:     } catch (IllegalStateException e) {

  15:         Log.e("ERROR",e.getMessage());

  16:     } catch (IOException e) {

  17:         Log.e("ERROR",e.getMessage());

  18:     }

  19:     return bmp;

  20: }

It might not be a good idea to catch those exceptions here as this involves some UI. But I caught them here. Do as you please, and keep to whatever the programming paradigm you are using.

After acquiring the Bitmap Image you can simply create a new android.widget.ImageView (make sure you include an ImageView in the layout as well) and pass the Bitmap to that image view. The activity will display the Image on the ImageView.

   1: public class ViewImageActivity extends Activity{

   2:     private ImageView imageView;

3:

   4:     @Override

   5:     protected void onCreate(Bundle savedInstanceState) {

   6:         //other methods & tasks

   7:         imageView = (ImageView) findViewById(R.id.ivInputInterpret);    //retrieve the ImageView widget from the layout

   8:         imageView.setImageBitmap(getBitmap(fullURL));    //set the retrieved Bitmap as the Image

   9:     }

10:

  11: }

If you have any issues or problems post them in comments. I’ll try to answer them as I can.

A small tip , if you’re looking for android development tutorials check these awesome tutorials. They’ve helped me a lot. I’m sure they’ll be of immense help to you all as well.

TheNewBoston - Android Application Development Video Tutorials [Youtube]

mybringback – tutorials

Trust me, those tutorials are pretty awesome!

So till I meet you guys soon again, adiós!

Google Chromebook

2011-11-16T17:27:00.001+05:30

This is a nice introductory video about Google Chromebook. Thought of sharing it because this video presentation just amazed me. It sounds really friendly, really cool.

Keeping my fingers crossed for buying one of these. =)

Tips | Copy Fast and It's made by Microsoft

2011-08-11T21:17:00.009+05:30

I'm gonna give you guys a quick tip today. There are lots of third party applications that can be used to copy files fast. But have you ever heard of RichCopy?

RichCopy is a tool that copies files super fast. Trust me, It is super fast! The best thing about it is, "It is made by Microsoft!!!". Yeah, you heard me right. Microsoft have made this tool for their internal usage. It was created by a Microsoft engineer named Dirk Benisch and was made in 1996. (Wonder why they didn't publish it though). But the good news is it's available for public download.

You can use it to copy a bunch of files or to copy a huge file super fast. Here's a screenshot of how it looks.

You can also create multiple profiles to cater your copying needs as well. Use the options.

Try it out and leave your opinions in the comments.

You can download it here or use the link below.

http://download.microsoft.com/download/f/d/0/fd05def7-68a1-4f71-8546-25c359cc0842//HoffmanUtilitySpotlight2009_04.exe

For more info read this Microsoft TechNet magazine post.
Hope this helps. =)

Tips | Are you a blogger?

2011-07-28T11:57:00.006+05:30

Are you a blogger? And are you using Windows? Then I could help you with your blogging. Did you know about Windows Live Writer? I guess not! It’s not something to be separately purchased, nor a 3rd party software. You may be surprised, but it has been there all the time though we didn’t know about it. I found this out somewhere, I can’t exactly remember, but this tool is pretty awesome when it comes to blogging. It can easily be integrated with blogger. (and with wordpress and many other tools as well) I’m using blogger, so I checked with it and I’m even posting this via Live Writer.

The out-of-the-box version of Windows Live Writer is pretty powerful, but you can get more out of it by upgrading it. You can download the Windows Live Essentials pack and custom install it.

Remove the unwanted stuff and customize the install.

Now you can open the Live Writer. But you might not be able to find it. To open it just type,

Windows Live Writer in your start menu search bar.

Once you open the Live writer for the first time, it’ll prompt you to integrate your blog. (after you accept their agreement of course. )

You can select the service you want from the above list. Since I’m using blogger I selected Other services. Hit next after that.

Enter the details of your blog and provide authentication. You’ll need an active internet connection from here onwards.

It’ll start loading your blog details.

Set the name of your blog here. (Not that important though)

This step is pretty important. Here it asks to fetch the theme of your blog. To do this it needs to publish a temporary post which will be deleted automatically afterwards. Select yes and let it do it’s work and fetch the theme.

IMPORTANT: If you’re using an app like NetworkedBlogs,you need to be careful here. Although the temporary post that is published by the Live Writer is deleted, the post, posted on facebook by NetworkedBlogs would NOT be deleted. You have to manually delete it from your facebook account.

This is how the interface looks like when you are done with fetching the template and all. Pretty cool isn’t it?

There are lots of cool features available via Live Writer for us, bloggers.

You can easily insert images + add a watermark to it.

Add various effects to your images.

Easily add tables to the post.

Add emoticons.

And finally when you’re done with the post, you can preview it and see how it would look in the actual blog. See the bottom left corner for viewing options.

Now if you’re ready to post this to your blog, you have two options. You can either post it straight to your blog or you can post it to the blogger dashboard as a draft.

I only mentioned some basic tools that we can use. Play around with the Live Writer and you'll find more stuff.

[EDITED]
You can add more functionality to your Live writer by installing Windows Live Writer Plug-ins. Download plugins from here.

I hope this tutorial was helpful for you all. Happy blogging! Tell me your experiences in the comments. See you all later in an another post. I’m out till then.

Tricks | Change your login screen

2011-07-22T01:00:00.011+05:30

Today I’m going to tell you all about a simple but neat trick. This is not a hard thing to do, and not risky at all, if you do exactly as I say. =)

Here I’m going to teach you how to change your login screen. It’s going to be simple 4 step process. Follow me on this.

STEP1: Locate the folder

First thing you have to do is to locate the folder where the login screen images are stored.

They’re located in your Windows directory.

Go to the default directory:

C:\Windows\System32\oobe\info\Backgrounds

Or you can get there easily by pressing, Win key + R and then pasting this in the run.

%windir%\System32\oobe\info\Backgrounds

It will direct you to the folder where the default images are stored. If the folders don't exist, don't worry. Create the folders in the exact path mentioned above.

Now you’ve successfully located the images folder, lets move on to the next step.

STEP2: BACKUP BACKUP BACKUP!

The most important rule in the world of computing. Backup everything! Simply copy all the images in the folder located previously(Backgrounds folder) and back them up in some safe place. [keep it guarded 24x7 if you can ;)]

After backing them up, delete all the images in that folder and empty it.

STEP3: Find the image you desire, copy it here

The next step is finding the image that you want to be your new login screen. It can vary from a LOLCAT to your girlfriend's photograph, totally up to you to select the image. Keep only one thing in mind, don’t find a huge image.(about 250KB max)

Once you found a suitable image rename it to BackgroundDefault. Copy that selected and renamed image to the (now empty) Backgrounds folder which was located in the STEP1. The folder should look like this when you are done with this step.

STEP4: Update the registry

Here comes the final step, and perhaps the most important of them all – updating the registry. First you should open your windows registry editor. To do this, simply open run command window (Win key + R) and type,

regedit

You should have the administrator privileges to do this. When you open the registry editor you have to locate the registry key. To do this press Ctrl + F and find this,

OEMBackground

That is the easiest way to do it. Don’t worry if it took some time.

Double click on the OEMBackground entry and change the Value data to 1. Press OK and close the registry editor. Then you are done for good.

You can download the image i used via this link. This is how it looks in the end.

Hope you guys enjoyed this. See you all soon with another post. Cheers!

P.S.:-
There are also software that can do this for you. If you prefer that you can find more details from here.

Check your IPv6 connectivity

2011-06-15T00:59:00.004+05:30

I believe now it's about time for us to panic. :O The legendary IPv4 addresses have all run-out! If you want to stay connected in the future you will eventually have to migrate into IPv6. Sooner the better it will be. Otherwise you'll literally die in the Internet. ;)

If you are already using IPv6 connectivity here's a web site where you can check the status of your connectivity by going through some tests. The web site was implemented by a talented set of undergraduates from Department of Computer Science & Engineering, University of Moratuwa. It was launched during the IPv6 day conference held on 08th June 2011.

The web site also has some really interesting information about IPv6 connectivity. So don't forget to have a look around the site as well.

Check your connectivity: http://www.ipv6day.lk/node/2

Await for more details on IPv6 connectivity...til then I'm out. :)

Google - Colorful - Awesome

2011-05-11T00:07:00.002+05:30

When we want to search for something everybody just Google, right? In fact "Google" has even become a verb now, arguably. =)

Well, the guys at Google - Chrome experiments have come across a cool new feature (as they always do) to display the Google search volumes. It looks really awesome. They have used different colors for each language and some bar-like MIND-BLOWING representation to show the Google search queries of a single day with respect to the location. And you've got to check this out. To see this you need a WebGL enabled browser (It worked well on chrome because WebGL is enabled in it, after all it was a result of a chrome experiment ;). Firefox couldn't load this page). You can check out this awesome search globe here.

You can see a similar kind of a world population globe, which also uses WebGL, here.
You can know more about The WebGL globe here.

Here are some screen caps of results of Sri Lanka and some results of few other countries in the world.

A quick post, hope you'll enjoy this. See you next time. And don't forget to follow. =)

Did you boot into Ubuntu again?

2011-05-06T01:12:00.011+05:30

Ooops, did you boot into Ubuntu again just because it's on top of the list? I know many of you who use multiple operating systems on a single computer face this problem. There are many ways to get over this problem. I use a simple method. The method is to let the the operating system of my previous login to be the default selection of my next login. It's a simple and effective method.

Here's how you can do it.

First Step: Boot into Ubuntu
Here you have to first boot into Ubuntu and then to open a new terminal.
Then you have to open the grub. I use gedit or you can use any text editor that you are familiar with. Simply enter this line in the terminal.

sudo gedit /etc/default/grub

Here sudo means you are requesting access as a power user. So you'd be prompted to enter your login password. Once you entered the grub will be opened in the text editor.

Second Step: Edit the grub
You have to be careful now. If you don't know what you're doing you should keep out from editing this file. But you'll be just fine if you do as i say. =)
After you opened the grub using a text editor you'll be able to see a line that says,

GRUB_DEFAULT=0

as in this screen cap.

You've to change that to,

GRUB_DEFAULT=saved

Then add this line to the file as well.

GRUB_SAVEDEFAULT=true

After editing the file will look like this.

Now save the file (simply press ctrl+s on gedit) and close the text editor. But don't close the terminal because it's not done yet.

Final step: Update grub
This is really important. You have to update the grub.cfg file in order to the changes to take effect. To do this enter this in the terminal.

sudo update-grub

If it prompts for the password enter it and let it do the necessary changes.

Now every time you boot in to the computer your last login selection will be selected by default. Restart the computer, login to the other OS and restart again and see that now your default selection is not Ubuntu...or whatever that was on top of the list, unless you selected it in your last login. Hope this helps you...catch you next time. Leave a comment if you've any problem. =)

Making your own Operating System - The Next Step

2011-05-01T19:31:00.007+05:30

Now you've successfully set up the virtual machine to boot from JOSH OS (If you haven't done it yet, read this post on how to do it), I'm going to tell you how to add a new functionality to display the hardware details of your computer.

There are three main methods to get the hardware information from the BIOS Data Area.

1. Use BIOS Service interrupts

By using various BIOS interrupts we can get the hardware information that are stored in the BIOS data area. Interrupt call will return the AX register with the corresponding information.

Ex:

xor ax, ax ;clear the ax register

int 0x11 ;send the interrupt, it sets the ax register

and ax, 0x0e00 ;keep the bits 9-11

shr ax, 9 ;shift 9 bits right

add al, 0x30 ;add 48 and convert to decimal

mov ah, 0x0e

int 0x10

2. Use BIOS Data area and access it using the offset

When a computer is powered on, the BIOS data area is created at memory location 0040:0000h with a typical size of 255 bytes. This data area can be accessed by calling the relevant offset where the required data is saved.

Ex:

push es ;save the current values of the es register

mov ax, 0x40 ;get the address no 0x40 to the ax register

mov es, ax ;move ax to the es

mov al, [es:75h] ;get the required offset to display no of HDD

add al, 0x30 ;convert the number to ASCII by adding 48(decimal) = 0x30

mov ah, 0x0e ;print the number

int 0x10

pop es ;restore the value stored in the es register

By using the table below we can find almost all the information of the hardware underneath the computer. We can use either,

calling BIOS service interrupts or

referring to BIOS Data area

to get the information needed.

Offset Hex	BIOS Service	Field Size [byte(s)]	Information
10h	Int 11h	2	Equipment word
			Bits 15-14 indicate the number of installed parallel ports 00b = 1 parallel port 01b = 2 parallel ports 03b = 3 prallel ports
			Bits 13-12 reserved
			Bits 11-9 indicate the number of installed serial ports 000b = none 001b = 1 serial port 002b = 2 serial ports 003b = 3 serial ports 004b = 4 serial ports
			Bit 8 reserved
			Bits 7-6 indicate the number of installed floppy drives 0b = 1 floppy drive 1b = 2 floppy drives
			Bits 5-4 indicate the video mode 00b = EGA or later 01b = color 40x25 10b = color 80x25 11b = monochrome 80x25
			Bit 3 reserved
			Bit 2 indicate if a PS/2 mouse is installed 0b = not installed 1b = installed
			Bit 1 indicate if a math coprocessor is installed 0b = not installed 1b = installed
			Bit 0 indicated if a boot floppy is installed 0b = not installed 1b = installed
13h	Int 12h	2	Memory size in Kb
17h	Int 16h	1	Keyboard shift flags 1
18h	Int 16h	1	Keyboard shift flags 2
1Eh	Int 13h	1	Keyboard buffer
41h	Int 13h	1	Floppy disk drive status
42h	Int 13h	1	Hard disk and floppy controller status register 0
43h	Int 13h	1	Floppy drive controller status register 1
44h	Int 13h	1	Floppy drive controller status register 2
49h	Int 10h	1	Active video mode setting
63h	Int 10h	1	I/O port address for the video display adapter
65h	Int 10h	1	Video display adapter internal mode register
67h		2	Adapter ROM offset address
69h		2	Adapter ROM segment address
6Bh		1	Last interrupt (not PC)
74h	Int 13h	1	Status of last hard disk operation
75h	Int 13h	1	Number of hard disk drives
8Ch	Int 13h	1	HDD controller status
F0h		16	Intra-applications communications area

3.Using special commands

In order to view the Processor details, we can use a special command which is provided by the processor manufacturers. The cpuid command requires no operands, but takes arguments from the EAX register. The value stored in the EAX register before calling the cpuid command, specifies what information is returned.

Argument given to the EAX register	Result
EAX=0	Get vendor ID
EAX=1	Processor Info and Feature Bits
EAX=2	Cache and TLB Descriptor information
EAX=3	Processor Serial Number
EAX=80000000h	Get Highest Extended Function Supported
EAX=80000001h	Extended Processor Info and Feature Bits
EAX=80000002h,80000003h,80000004h	Processor Brand String
EAX=80000005h	L1 Cache and TLB Identifiers
EAX=80000006h	Extended L2 Cache Features
EAX=80000007h	Advanced Power Management Information
EAX=80000008h	Virtual and Physical address Sizes

Ex:

_show_CPU_VendorID:

;******************read CPU vendor ID

mov eax,0

cpuid

mov [vendorID], ebx

mov [vendorID+4],edx

mov [vendorID+8],ecx

call _display_endl

mov si, strVendorID

mov al, 0x01

int 0x21

call _display_space

mov si, vendorID ;print CPU vender ID

mov al, 0x01

int 0x21

ret

;end

The material below helped me to complete this assignment…Hope they’ll be helpful to you else also.

Hexadecimal to decimal conversion

The procedure given below will convert the value stored in the DX register to decimal and print it character by character using decimal to ASCII conversion.

_hexToDec: ;convert hex to decimal

push ax

push bx

push cx

push si

mov ax,dx ;copy number into AX

mov si,10 ;SI will be our divisor

xor cx,cx ;clean up the CX

_non_zero:

xor dx,dx ;clean up the DX

div si ;divide by 10

push dx ;push number onto the stack

inc cx ;increment CX to do it more times

or ax,ax ;end of the number?

jne _non_zero ;if not go to _non_zero

_write_digits:

pop dx ;get the digit off DX

add dl,0x30 ;add 48 to get the ASCII value

call _print_char ;print

loop _write_digits ;keep going till cx == 0

pop si ;restore SI

pop cx ;restore DX

pop bx ;restore CX

pop ax ;restore AX

ret

_print_char:

push ax ;save the current AX register

mov al, dl

mov ah, 0x0E ;BIOS teletype acts on newline

mov bh, 0x00

mov bl, 0x07

int 0x10

pop ax ;restore the AX register

ret

;end

If you need to have a look at what i implemented here is my kernal.asm file. Below are the methods I implemented. If you can't understand any, feel free to ask me. :)

Method	Action
_display_hardware_info:	Display hardware information invoked by “hinfo” command
_show_CPU_VendorID:	Show CPU vendor ID
_show_Processor_Brand:	Show processor brand
_show_floppy_info:	Show available number of floppy drives
_no_floppyD:	If no floppy drives found print 0
_available_floppyD:	Print the number of floppy drives
_show_serial_info:	Show number of installed serial ports
_show_parallel_info:	Show number of installed parallel ports
_show_memory_info:	Show RAM size
_remove_cx_conflict:	Some bioses return CX=BX=0 if so copy ax to cx and bx to dx
_memCalculate:	Calculate and print the memory size
_MemErr:	If an error occurred print the error
_show_HDD_info:	Show number of installed Hard Disk Drives
_show_Mouse_status:	Show if a PS/2 mouse is installed
_print_true:	Print “true”
_print_false:	Print “false”
_display_custom_msg:	Display a custom message stored in the strTest invoked by “who” command
_display_help:	Display help invoked by “help” command

Here's list of what i referred while doing this assignment. A big thank goes to all of them.

[1] Hacking JOSH– Operating System Tutorial « Asiri's Laboratory

http://asiri.rathnayake.org/articles/hacking-josh-operating-system-tutorial/

[2] Operating System design &implementation Tutorial, planning a interrupt service ISR

http://www.mohanraj.info/josh5.jsp

[3] Expanded Main Page - OSDev Wiki

http://wiki.osdev.org/Main_Page

[4] BiosCentral - BIOS Data Area

http://www.bioscentral.com/misc/bda.htm

[5] NASM - OSDevWiki

http://wiki.osdev.org/NASM

[6] Detecting Memory (x86) - OSDev Wiki

http://wiki.osdev.org/Detecting_Memory_%28x86%29

[7] Detecting CPU Speed - OSDev Wiki

http://wiki.osdev.org/Detecting_CPU_Speed

[8] INT (x86 instruction) - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/INT_(x86_instruction)

[9] Assembly Tips and Tricks « CyberAsylum

http://cyberasylum.wordpress.com/2010/11/19/assembly-tips-and-tricks/

[10] CPUID - Wikipedia, the freeencyclopedia

http://en.wikipedia.org/wiki/CPUID

So that's about it for now. A long post, i guess. Hope this helps you guys. Please feel free to leave a comment on anything you need clarification. There are lots of resources available in the Internet. So don't be afraid to mod your OS by adding more features. Have fun with it. Bye for now. :)

Ever wanted to drive while Police cleared the road for you..??

2011-04-30T21:26:00.004+05:30

I'm sure you all have seen VIP vehicles moving while the police cleared the road for them. Have you ever wanted that to happen to you? Have you ever wanted to have police clear the road for you while driving? Well, I might have a solution for you. :)

This happened to me today. I was going to the town in the morning and there happened to be a bicycle race on the road. For me it looked more like a Motorcycle race, anyway, that's an another discussion. A van lead the race announcing blah blah blah...and two traffic police motorcycles followed them. (Here comes the more important part) The police was clearing the road for the cyclists following them. I moved the car to the side and let them pass me. The van, two police bikes and 3 cyclists passed me, along with about 25 motorcycles ;) and a jeep followed them with hazard lights on. And that was it. when they passed me I started following them. I couldn't overtake them, I don't like traffic police much :P , and boy those cyclists were fast!

After few minutes I could see that road was clear, because the police was clearing the road, even the people in my lane sided there vehicles and let them pass, and I also moved along, comfortably passing the sided vehicles. It is then i realized that it was like the police has cleared the road for me. =D

Simple method, isn't it? But you've got to hurry, the "avurudu uthsawa" season is about to end.

And if you want more, just switch on the hazard lights of your vehicle also. Believe me, it's FUN..!!!! =D =D =D May be that jeep was also following them like me, I'd never know.

Call me crazy, but this works. True Story!

Making your own Operating System - Getting Started

2011-01-12T00:52:00.001+05:30

This is my first actual technical blog article. So as a starter I'm going to guide you all through a tutorial on making your own Operating System. (Yeah..I'm not kidding..it's going to be an up and running OS)

This was an assignment that was given to us at the University. So just thought of sharing it with you all, because it was one of the assignments i enjoyed doing, and this might help someone in the future...

Assuming that you have a Linux distro installed [I'm using Ubuntu during this walk through.] and that you know how to work yourself around a little bit..(If you don't, feel free to ask, I'd be happy to help you.) lets take the first step...

The first step would be to follow this tutorial by Mr. Asiri Rathnayake ...it provides the necessary initialization.
Hacking JOSH – Operating System Tutorial

After confirming that you can successfully boot from the image in your pen drive, lets do some modding.

Tip#1: During the process of modifying the OS, you'll have to enter some code and to restart the computer with JOSH OS to try out your code. Instead of having to restart your computer all the time, you can easilly use a virtual machine. To do that you need a bootable image file. Here's how you can get one for yourself.

Open the terminal and create a directory for floppy drive,

sudo mkdir /media/floppy0

Then you have to create an image of the pen drive which you modified using the tutorial provided above...

sudo dd if=/dev/sdb of=/JOSH.img

mount that image in the drive,

sudo mount -o loop -t vfat /josh.img /media/floppy0

Then give that floppy drive as the boot device for your virtual machine.

I'd suggest Virtual box or the qemu as the virtual machine but you can't use them both. qemu is faster and the Virtual box is more user friendly. Both are free.. :)

Install qemu using this command,

sudo apt-get install qemu

Then you can mount your image using this command,

qemu -fda /JOSH.img

If you decided to use VirtualBox then it's fairly easy, because it has a wizard to help you with it. Here's a little help.

Open VirtualBox and create a new Machine. Set the settings as you desire.

Operating system - Other
Version - Other/Unknown
Base Memory Size (RAM Size) = 64MB (default)
Remove the tick from the "Boot Hard Disk" option
Next => Continue => Finish

Select the settings option of the created machine and go to Storage
The Floppy Controller will be empty...select that "Empty" label and select the Floppy device and click the button next to it..It will pop up the Virtual Media Manager window. Under that window select Add=> and locate your JOSH.img file.

Press Start and try out.

Go on, knock your selves out and try to boot from the JOSH.img.
Type this in the shell,

ver - it will print the current version.

Try to open and read the kernel.asm file and do some changes. Next time we meet here, I'll tell you how to show the hardware information of the computer using our JOSH OS.

Don't be afraid to work around in a virtual machine, after all it's virtual. ;)

Have fun!

PS: Read the Next Step to create your own Operating System here.

Reborn in the world of Bloggers

2010-04-27T22:40:00.000+05:30

Well..this is my first experience of being a Blogger. So here I am and bear with me if i make any mistakes while working with the blog..
If i feel there's something i should post in the Blog, i'll post it here. So it'll mostly contain techno gadgets, mobile phones, latest software and all that. And may be some memories from my life.

Hope you'll enjoy reading my Blog....
Let the game begin...