What apple advises you to do is to make a backup of you’re songs you bought in the iTunes store. The problem I have with this type of ‘buying songs’ is that you do not buy the actual song but you buy a single download for the song; also see this Apple support document confirming that. If I buy a song in the iTunes Store I expect to buy a license to download and use this song on my Mac and iPhone for the rest of my life. But it’s not, if my hard drive crashes and I have no backup then I have to buy all my music again. That is why I think you better of with buying the album on compact disc.

Let’s take a look at this example for the album “U2 – No Line On The Horizon”.

However some users are reporting that it is possible to contact Apple and they will allow you to redownload you’re songs again. But shouldn’t you’re music be licensed to you’re Apple ID and make it possible to download you’re music again after a hard drive crash? And maybe limit this to once a year as an anti-pirating feature?

And that’s why I don’t use the iTunes Store anymore to buy music.
An Apple fan.

Sending SMS messages with PHP

The first thing I needed was a device to send a SMS to the cellular network, also know as a cellphone. I connected this phone to my server by Bluetooth. Then I established a connection between the cellphone and the server over Bluetooth so I could send AT commands to the phone. These AT commands make it possible to talk to the internal modem of a cellphone, for example to send a SMS. More information about AT commands can be found on these pages:

• AT Commands for GSM
• How to send SMS Text Messages in PDU mode

Let’s assume you have a working connection to your cellphone and understand what AT commands are. Now you need a way to convert a text message like “Hello!” into a PDU formatted string. Converting this text message to PDU can be difficult. So I wrote a text to PDU conversion script in the form of a PHP class. In this blog post I want to share this class with you. If a lot of people want me to detail the full “PHP to cellphone” setup I will write an blog post about it later on.

PHP PDU class

The PHP PDU class provides you an easy way to convert text messages to PDU formatted strings. The only thing you have to do is fill the message and the receiving cellphone number. The PHP PDU class will convert these parameters to the PDU format.

Example usage: (a more detailed example is in the download)
<?php
$pduGenerator = new Pdu();
$pduMessage = $pduGenerator->generatePDU('0612345678', 'This is a text message.');
?>

Because each cellphone has it’s own implementation of the PDU format the returned PDU message may not work for you. I tested this class with a Sony Ericsson cellphone, which worked great. But it is possible that you need to modify the class for other cellphone brands. If you do, please share these modifications in the comments along with the cellphone brand and model type.

More information about the PDU format:

• SMS and the PDU format
• Javascript PDU converter

Feel free to give me tips and feedback on the code. I wrote this script a long time ago, so it could be improved. I hope you like it.

Download

Download the PHP PDU class. (PHP PDU 1.0.tgz)
MD5 Hash: c181815c10707440edd8a1dd2b392cb8

License

Commercial use of this class is not allowed. If you like to use this code in any kind of commercial way or need this code under any other license please contact me.

PHP PDU by Vincent Heet is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Netherlands License.
Based on a work at adevelopersblog.com.

1. Open up the Terminal “Applications > Utilities > Terminal”
2. Enter the command: “rm -rf ~/.Trash/*” (without the quotes of course)
3. Hit enter
4. The files are removed, if not you could execute this command again with “sudo” before it. This makes you a super user which has more rights to remove files. But be careful you could harm your Mac. The full command will look like this: “sudo rm -rf ~/.Trash/*”

Disclaimer: adevelopersblog.com posts are provided “as is”, without warranty of any kind, whether expressed or implied. adevelopersblog.com is also not responsible for any damage or loss of data. Always make sure you have a backup of all your data before using the information in this post.

Update all your software
Use the Apple Software Update but also check all the other applications on you’re system for updates. This gives you the most recent software with the latest bug fixes and frequently some speed optimizations. You won’t see a big improvement in speed but you get a more stable system and sometimes even a little bit snappier.

Clean up your login items
This is a classic tip, which is very easy. Remove the unused login items by navigating to “System Preferences > Accounts > Login Items”. Select the software items that you don’t need any more and click the minus button.

Reset the PRAM and NVRAM
This is an advanced trick which could speed up you’re boot-up time significantly. For example my MacBook Pro boot up took very long. It was waiting on the first grey screen, just before the loading indicator appears. After resetting the PRAM of my Mac the time was shortened from 8 to 2 seconds. More information about the PRAM reset can be found on the Apple website: http://support.apple.com/kb/ht1379

Use Onyx
Run Onyx once a month on “Automatic” mode to clean the caches. This is not a guaranteed speed improvement but it is not bad to clean the caches once in a while. It is possible to get a corrupt cache file which will slow down you’re Mac.

Check the Console (advanced users only)
If you’re an expert Mac user you are able to do some other speed improvements but be warned this can harm you’re Mac.

• Startup the “Console” application by going to “Applications > Utilities > Console”
• Find and select “All Messages”
• On the left you will see a windows with messages. These ‘log’ messages are send by the applications running on you’re Mac.
• Search for the first log message of this system boot. You can identify this by the time difference between two messages. Take a look at the image for an example. In the image you see that my system booted at 18:57.
• Read all the upcoming messages to look for potential problems. Just scroll trough these messages and search for errors and warnings, or even software you are not using anymore. For example: I found out that there still was some VMWare Fusion software booting which I don’t use anymore.
  • Solution 1: Indentify the messages and search for a solution.
    Some times just searching for the logged problem in Google will give you a good idea about the issue. But make sure you have more than one source when for the proposed solution. You could still harm you’re Mac by executing the proposed solution.
  • Solution 2: Look in the “LaunchAgents”, “LaunchDaemons” and “StartupItems” folders.
    Take a look in these folders which you will find in “~/Library” and “/Library”. (If you don’t know how to find these folders this guide probably isn’t for you.) After opening each of these folders you have to look for files/daemons from the software that is reporting an error or that you don’t use anymore. You can easily remove these items but be careful you could do some damage to you’re computer. That is why it is important to backup the removed files from these folders to another folder. For example to a backup folder on you’re desktop so you can restore the files if a problem arises.

Disclaimer: adevelopersblog.com posts are provided “as is”, without warranty of any kind, whether expressed or implied. adevelopersblog.com is also not responsible for any damage or loss of data. Always make sure you have a backup of all your data before using the information in this post.

This behavior is very strange and I did never saw something like this before. After searching the internet I could not find any information about this double scrollbar problem. So I had to try other things. What I always do when I have an issue like this is ‘clean’ the page. I remove some div’s and Javascript to see when the issue is resolved. After a while I removed the jQuery library from the code and the issue was fixed. No double scrollbars anymore in IE6. That was a nice find but we did need jQuery for the website. So I upgraded jQuery and the double scrollbar issue was gone and the site was functioning again. (Another good reason to keep external libraries up to date.)

So IE6 displayed only one scrollbar now as it should. The ‘other’ browsers (Firefox/Safari) still worked of course. Then I started testing the site and a new problem appeared in Internet Explorer 6. When showing or hiding a div with the jQuery .show() and .hide() methods the scrollbars started to move. Wow! That is a new IE6 problem I had never seen before. After a lot of searching and debugging I was thinking about the 100% width/height fix that I did at the beginning. After removing this fix the moving scrollbar issue was gone but again no scrollbars on all the pages.
After searching for fixes again on this issue I did found the final solution which is a very nasty HTML fix. By applying the ‘scroll=”yes”‘ attribute to the tag I managed to fix the scrollbar issue finally. I know it is a very ugly solution but some times you have to do concessions on the quality of your code.

Having double scrollbar issues?
- Update jQuery to the latest stable release
- Apply the scroll=”yes” option to the body tag Example:
<body scroll="yes">The content.</body>

I hope someone will stumble up on this post when searching for your own IE6 scrollbar problem and maybe even fix it with the information in this post. Good luck!

Single quoted style.
$text = 'This is a small text.';
Double quoted style.
$text = "This is a small text.";

When using the single quoted style you force the string between the quote’s to be a ‘real’ string without any special characters or variables. By special characters I mean characters like new line breaks ‘\n’ or a carriage return ‘\r’ for example. Yes, special characters and variables are supported in the double quoted style, lets take a look at this example.

// Double quoted
$name = 'John';
$text = "Hello, $name";
echo $text; // Result: Hello, John

// Single quoted
$name = 'John';
$text = 'Hello, $name';
echo $text; // Result: Hello, $name

As you can see the single quoted style takes the string and won’t do any transformations on the data between the quote’s. The double qouted style finds a variable $name and copies its content into the string variable $text. But what if you want to use the variable $name and single quotes?

// Single quoted (working)
$name = 'John';
$text = 'Hello, ' . $name;
echo $text; // Result: Hello, John


I prefer the last way of working because of the following reasons. First of all it looks a lot cleaner to me and you will see that you’re strings are really strings with variables attached to it (dot means concat). And not some string with a variable hidden in it. For you and other developers it will be a lot easier to skim the PHP code and see where that variable is hidden. The other reason is performance. Using single quotes and concat is slightly faster than double quotes, as described here.

For more information about the string type in PHP you can read this page. On that page is also a list of ‘special/escaped characters’ which will not work as you may expect when using in single quoted strings.