Snippet IT

iOS 5.1 Unable to Update

admin — Mon, 12 Mar 2012 17:33:14 +0000

Apple has recently released their latest OS for iPhone/iPad/iPod, the iOS 5.1. However I have difficulty in downloading the updates both from my Macbook or iPhone. It just hang without any response. I tried for a few days but I just can't download the updates.

After some trial and error. I found out that actually the update software cannot find the update server's host name. So to fix this problem, you just need to set you Mac/PC/iPhone's DNS to an open/well know DNS so that the update software can find the exact location of the host name. I use Google's open DNS and I can now download the updates without any issue.

Hope this information helps you too!

eGenting Programming Competition 2011

szehau — Tue, 13 Sep 2011 02:34:09 +0000

Calling all talent programmers! eGenting Programming Competiton 2011 is now open for registration! Do you dare to come?

Below are the details of the event:

Competition date: 29 October 2011 (Saturday)
Time: 10.00 am to 6.00 pm
Venue: Auditorium, 25th Floor Wisma Genting, Jalan Sultan Ismail, 50250 Kuala Lumpur
Nature: Open-book handwritten programming task

The prices:

1st Price - RM6,000
2nd Price - RM3,000
3rd Price - RM2,000

Be sure to like our facebook page as well

New Top-Level Domain – Dot Whatever

szehau — Mon, 20 Jun 2011 15:58:46 +0000

ICANN (Internet Corporation for Assigned Names and Numbers) has recently approved new top-leve domain name. Currently, the web has .com .net .org or country level TLDs. Soon you can expect to have .whatever domain (whatever means whatever).

To have this kind of domain is not cheap. The application alone is $185,000 and the annual fee is $25,000. I wonder why the application fee and the annual fee is too expensive. I think it is meant to control the number of people that own the domain names.

The application for the new generic will be accepted from January 12, 2012 to April 12, 2010 and the new domain name will be appear on the Internet within a year.

Personally I think this is a great idea because it may cause confusion to most people. People might not be able to differentiate a company domain from a government domain for instance.

Google Adsense: Now available for mobile (beta)

szehau — Thu, 03 Mar 2011 18:58:32 +0000

Google Adsense is now available on mobile. It is still in beta mode and I have tried it now just now, not much feature but it us pretty good. You can see earnings and graphs.

However it is great that now you can see your website earning on your phone!

Point your browser on your mobile device to Google Adsense website and it will bring you to the mobile version of Adsense website.

Gmail: Priority Inbox

szehau — Sat, 11 Sep 2010 14:58:03 +0000

Gmail is great and comes with a lot of useful features like labeling and filter to let your organize your mail box. Although these features are great but they work according to preset or static values. They are not smart enough.

It becomes a problem when you have too much of unread emails. What if a bunch of emails come in at the same time? It could be a pain to find out which email is important to read first.

Now, Gmail introduces a new feature called "priority inbox". As its' name means, it prioritizes your emails according to how frequent you read the email from a sender, how frequent you reply email to a sender and etc. It's automatic and smart. If anything goes wrong with Gmail's intelligence, you can manually mark the email as important or as not important.

Take a lot at Priority Inbox and try it out!

[Read more]

Unix Shell Script: How to Receive Input Right After Echoing A Line

szehau — Mon, 16 Aug 2010 13:21:23 +0000

For example, say I echo a line of text in shell script and I want to receive user input just right after the text (not in the next line). The are several ways to do it:

Method 1

echo "Enter a value: \c" read value

Method 2

echo -n "Enter a value: " read value

Method 3

read -p "Enter a value: " value

Database: CHAR and VARCHAR – What are the differences?

szehau — Sun, 30 May 2010 15:28:01 +0000

Most programmers may already know the main different between CHAR and VARCHAR - The first one supports fixed-length data and the second one supports variable-lengths of data.

Some people may think, since VARCHAR can do what CHAR does, then why we still need CHAR in our database design. I even have heard one of the very experienced Oracle database administrator say "Nowadays nobody is using CHAR anymore, you can forget about putting CHAR column in your database design".

The statement is not totally right. Even though VARCHAR can do what CHAR does, CHAR does has certain level of advantages over VARCHAR in terms of performance, efficiency and space.

I think it is good for a database designer to know how a database is being design. In other words, to think how a database programmer will design the database management system (DBMS) for the best performance and efficiency.

1. When a table column size is quite small, for instance 1 to 4 bytes, using CHAR helps save more space then VARCHAR. This is because DBMS will need additional few bytes (depends on database limitation for VARCHAR) to keep track the length of the data (all the rows) for the VARCHAR column.

2. Since VARCHAR can keep variable size of data, therefore it needs to keep track the length of the data for all the records. Therefore it adds little overhead to the DBMS's performance if compared to CHAR.

3. DBMS (I would say most systems) keeps fixed-length data and index more efficiently. Retrieving and updating data from and to a fixed-length row table is faster then a variable-length row table.

Therefore, I think CHAR is still very useful. We should always use CHAR if the column size is small enough or the data input is always going to be the size of the column (e.g. most of the data is in 10-12 bytes size and the column size is 12 bytes), so that we can get better performance for our application.

Java: Use ByteBuffer As InputStream

szehau — Mon, 11 Jan 2010 17:05:38 +0000

Sometime, your program may need to read data from a ByteBuffer buffer into a InputStream object. There is no class in Java library that provide the facility to do the conversion.

Anyway, to use a ByteBuffer object as an InputStream is pretty simple. What you need to do is to write a class wrapper that inherit InputStream and override the read() function in InputStream.

Here is the example:


public class ByteBufferInputStream extends InputStream {

  private int bbisInitPos;
  private int bbisLimit;
  private ByteBuffer bbisBuffer;

  public ByteBufferInputStream(ByteBuffer buffer) {
    this(buffer, buffer.limit() - buffer.position());
  }

  public ByteBufferInputStream(ByteBuffer buffer, int limit) {
    bbisBuffer = buffer;
    bbisLimit = limit;
    bbisInitPos = bbisBuffer.position();
  }

  @Override
  public int read() throws IOException {
    if (bbisBuffer.position() - bbisInitPos > bbisLimit)
      return -1;
    return bbisBuffer.get();
  }
}

In this class, ByteBufferInputStream, you can specify the limit to read from the ByteBuffer so that you can use the data in ByteBuffer later for other purposes. The read behavior is same as other InputStream class, where when there is no more data to read (or reached the preset limit), the read() function returns negative one.

100th Posts For Snippet IT

szehau — Mon, 11 Jan 2010 16:53:55 +0000

Finally, this blog has reached 100 posts! Yeah!

It really takes a long time for me to do this because I'm not blogging this site full timely. Second, sometime I'm just out of idea what to blog.

I will try work harder to share more information on programming and anything related to information technology in this new year. Thanks for reading!

Java: Format Integer Into Fixed Width String

szehau — Mon, 04 Jan 2010 17:36:47 +0000

Sometime, you may want to format an integer or a long value into a fixed width String. You need to display the value in fixed width especially in reports where you want to keep the numbers in aligned (e.g. 3456 as 0003456 and 1234 as 0001234).

Other than that, you may also want to format the integer value for a better visibility. For example, to display integer value as a document number (e.g. 12345678 as 00-01234-5678), for example an account number.

The Java.format() is not flexible enough to solve my problem. At least it cannot be used to format a fixed length document number in the format I want: XX-XXXX-XXXX. Therefore I decide write my own format function.

The following function format a integer value into a fixed length String.


public class IntegerUtil {
    public static String formatFixedWidth(int value, int width) {
        char[] chars;
        int i;
        int c;

        chars = new char[width];
        for (i = 0; i < width; i++) {
            c = value % 10;
            chars[width-i-1] = (char)('0' + c);
            value = value / 10;
        }
        return new String(chars);
    }
}

To format the document number like the one I said above, you simply modify the source code above to add one or two lines code to append a "-" to the String when the loop iterate to the place where you want to put the "-". Remember to increase the characters buffer as well.

The following function shows a sample implementation of my document number format.


public class IntegerUtil {
  public static String formatDocumentNumber(int value) {
    char[] chars;
    int i;
    int c;
    int size;

    size = 10+2;
    chars = new char[size];
    for (i = 0; i < size; i++) {
      if (i == 4 || i == 9) {
        chars[width-i-1] = '-';
        continue;
      }
      c = value % 10;
      chars[width-i-1] = (char)('0' + c);
      value = value / 10;
    }
    return new String(chars);
  }
}

Happy Holidays from your Google team!

szehau — Mon, 21 Dec 2009 14:40:20 +0000

I just got a greeting card from Google Team. Do you have one?

The email entitles "Happy Holidays from your Google team!". Opps... when do I have a Google Team that works for me? Ha ha.

Anyway thank you Google! Happy Holiday too.

Google Wave Invitation Giveaway

szehau — Sun, 20 Dec 2009 12:20:12 +0000

I got my free Google Wave invitation from LiewCf, thanks for the invitation! Ok, now is my turn to give you guys, my blog readers, the free invitations.

First impression to Google Wave

To me, Google Wave is like a chatting program (e.g. MSN) where a few people can have collaboration in a channel (the Wave). Everything can be happened in real time (e.g. the message you type) and everyone in the Wave can see the chances in real time (almost). And it is also like a social website (e.g. Facebook) too where you can put in applications (Gadgets) and use it within a group of people.

How to Get a Free Google Wave Invitation?

It's very simple. All you need to do is to leave a comment in this post (with your email address) and state that you want to have a free Google Wave Invitation.

You will not need to do anything else in order to get the invitation but it would be appreciated, if you could subscribe to my blog feed. Thanks.

Be hurry, I only have 8 invitations in total. First come first served.

Invitations left: 1

Note: It may take some time to get the invitation arrive to you inbox (as according to Google Wave).

WordPress: Version 2.9

szehau — Sat, 19 Dec 2009 11:58:35 +0000

The latest WordPress version 2.9 is now available for download. The new WordPress has a new codename - Carmen - which is named in honor of magical jazz vocalist Carmen McRae (whom were added to the Last.fm WP release station).

Here are the cool stuffs from user point of view and feature highlights:

Global undo/”trash” feature - trash is added to the blogging system where you can temporary put the unwanted things (e.g. post and comment) in the trash. You can undo the action by restoring the deleted item from the trash too.
Built-in image editor - This is pretty cool when you want to have control over you images. You can edit, rotate and etc like how you do it in an image editing software.
Batch plugin update and compatibility checking - Update all you plugins at once without having clicks for each one. It is also now support compatibility checking to see if the plugin compatible with your current version of WordPress.
Easier video embeds - Inserting videos to post is now much easier. Instead of copying codes and paste it to your post under HTML mode. You can now simply copy the URL of the video to WordPress and it will do the rest for you. The following websites are supported: YouTube, Daily Motion, Blip.tv, Flickr, Hulu, Viddler, Qik, Revision3, Scribd, Google Video, Photobucket, PollDaddy, and WordPress.tv

There are a lot more features have been added to the new version of WordPress such as to support better SEO, new TinyMCE and etc. Visit WordPress Blog for WordPress Version 2.9 to read more about it.

To start upgrade, simply click on the upgrade link on top of the admin page after you have logged in as an administrator. If you don't see the link, you can kick start the upgrade by clicking the "Tools -> Upgrade on your left side bar of admin page to check for unpgrade.

If you are new to WordPress, you can download the latest WordPress here.

Adobe Acrobat Reader: Possible Security Vulnerability When Acrobat JavaScript Is Enabled

szehau — Thu, 17 Dec 2009 16:16:43 +0000

It is possible to have security vulnerability in Adobe's Acrobat Reader if the Acrobat Javascript option is enable.

When the option is enabled and you open a crafted PDF file with Adobe Reader that allows JavaScript execution, your computer will be exposed to security risk - hacker may able to access your valuable data from your hard disk.

JavaScript is a scripting language that is tend to be safe to be used in web browsers due to its limitation to access to client computer. Since it is safe, your antivirus software may not able to detect a pdf file with Javascript is actually contain an virus.

To prevent the security vulnerability, you should now check whether your Adobe Acrobat's Javascript option is enabled. If it is enabled, disable it as soon as possible. The default setting for Acrobat Javascript is set to enabled for most of the Acrobat Reader version.

To disable the option, open your Acrobat Reader application, click on Edit -> Preferences and a window will pop up. Select the "JavaScript" option from your left and make sure the "Enable Acrobat JavaScript" option is un-ticked.

Thanks for Walker for heading up the Acrobat JavaScript issue.

Java: Continuously Read Data From FileChannel Without MappedByteBuffer

szehau — Thu, 17 Dec 2009 11:46:01 +0000

When programmer writes a program to read data from a file continuously and sequentially with a fixed data type reading sequence (e.g. to read three integers then 2 doubles repeatedly), he or she may find the MappedByteBuffer from Java library is useful.

MappedByteBuffer is pretty useful because its content is a memory-mapped region of a file. Program can access to the position of the file it wants directly. It also does some optimization on loading data from file, where part of the content are loaded into memory before the read action is actually performed. But when the data will be load? It remains unknown and it is operating system dependent. This is the first problem when using MappedByteBuffer - are the data buffered?

The second problem arises when programmer uses MappedByteBuffer to read a big file. MappedByteBuffer only allows data reading up to the maximum value of an integer (2,147,483,648 bytes). If the program needs to read further from that, it will need to re-map the file by calling the FileChannle.map function by parsing in the correct file position. The programmer will need to be very careful in passing the correct file position because some time it can be very confusing.

To overcome these two problems, we can introduce, design and write a new class that ensures the data reading action is buffered for the best performance and also allows continuous of reading without the need of re-mapping the FileChannle. First, let's write out the pseudo code for the read file action:


get data (e.g. get integer)
  ensure the memory buffer has enough data for the requested data type
    if not enough, read data from file
read the data from buffer and return them in the requested data type

Below is the example of implementation:


public class FileChannelReader {

  private final static int BUFFER_SIZE = 64 * 1024; // 64k

  private ByteBuffer readerBuffer;
  private FileChannel readerFileChannel;

  public FileChannelReader(FileChannel fileChannel) {
    readerBuffer = ByteBuffer.allocate(PAGE_SIZE);
    readerFileChannel = fileChannel;
    readerBuffer.clear();
    readerBuffer.flip();
  }

  // Ensure the buffer has enough data
  private void ensureData(int size) throws IOException  {
    if (readerBuffer.remaining() < size) {
      readerBuffer.compact();
      if (readerFileChannel.read(readerBuffer) <= 0)
        throw new IOException("Unexpected end-of-stream");
      readerBuffer.flip();
    }
  }

  // Get current position
  public long position() throws IOException {
    return readerFileChannel.position() - readerBuffer.remaining();
  }

  // Set current position
  public void position(long position) throws IOException {
    readerFileChannel.position(position);
    readerBuffer.clear();
    readerBuffer.flip();
  }

  // Get integer
  public int getInt() throws IOException {
    ensureData(Integer.SIZE/8);
    return readerBuffer.getInt();
  }

  // Get long
  public long getLong() throws IOException {
    ensureData(Long.SIZE/8);
    return readerBuffer.getLong();
  }

  // And so on ...
}

I'm using this technique in my programming projects and it performs pretty well. The data to be read is always ensured to be buffered and it also reduces complexity in writing a program to read data sequentially.

Snippet IT

iOS 5.1 Unable to Update

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