Hi,

I recently updated my blog categories.  If you have (or had) hard time finding what you were searching for, please submit a comment to this post and I will rectify.

I also made tags navigation available.  The list of tags is displayed just under the category of a post.

Thanks.

Pascal.

If some of you have been using PHP on Windows with SQL Server 2005, you may have hit some problems especially if you wanted to exploit new features of SQL Server 2005 like xml datatype, NVARCHAR(MAX), etc.

The driver that had the better support for these were the PHP ODBC wrapper combined with the SQL Server 2000 ODBC driver.  The bad news is, by default, PHP ODBC uses server-side dynamic cursors which is the thing Microsoft says to avoid as much as possible (unless you have a need for that).  It is very slow, server resource intensive, poor performing, etc.

Some succeeded to change the way ODBC were handling resultset by using a hint at connection time (SQL_CUR_USE_ODBC), but it didn’t help for us.  Some perfectly valid parameterized queries where just giving unexpected results.

I even downloaded PHP’s source code to see why it was using dynamic cursors by default.  If I could, at least, change the default cursor, we may had a little performance increase…  It was hardcoded to “dynamic” with the following comment on top of it:

Try to set CURSOR_TYPE to dynamic. Driver will replace this with other type if not possible.

So next thing would be to change it and recompile…  forgot about it!

Then, some time at the end of 2007, I discovered an alpha community preview release of a new driver made by Microsoft.  Wohoo!  This version was unstable with xml datatypes at a point that it was making my Apache server crash… 

Fortunately, the official release finally got out et we are testing it for some time now!  So far, there are no blocking bugs.  The quality is good enough that I took the time to created a Creole wrapper (our web application uses Creole as database wrapper API) for it and start using it full-time on our develpment environment.

Here are some observations:

• On my laptop, based on a non-official, non-extensive performance test, I had a 400% to 500% performance boost for fetching 200 records of a large (numerous fields) table.
• UTF-8 support exists, but conversion must be done manually, field by field (better have a database wrapper API…) and at a huge performance cost.
• UTF-8 support works only for query parameters and resultset values.  If you hardcoded a query filter (I know it is not a best practice, but we all supports legacy applications…) you will have to rewrite it with parameters or drop UTF-8 support.
• If you are using PHP from a Linux server, you are still left alone because the Microsoft driver relies on the ODBC SQL Server Native Client driver that works only on Windows.

If you need more information about the driver, you can visit the Microsoft blog and forum.

First of all, for simplicity, let’s assume we have a desktop at home that we want to connect to (control remotely) using a laptop while we are at a friend’s home. We will use Remote Desktop to connect from the laptop to the home desktop. The home network is behind a router (firewall) compatible with Tomato (ex: Linksys WRT54GL).

Remote Desktop is a server application that uses TCP/IP network to enable remote control of a machine. It opens the port 3389 to handle network communications. By default Remote Desktop is disabled on Windows XP.

How to enable Remote Desktop on Windows XP (on the home desktop):

Start the system properties in the Control Panel (or right click “My Computer” and click properties). Go to the “Remote” tab. Enable remote desktop by checking “Allow users to connect remotely to this computer”. Note 1: Don’t forget to set a password on the user you intend to use to connect remotely because Remote Desktop will prevent connection with blank passwords. Note 2: By defaut, only users with the administrative priviledges are allowed to connect remotely.

At this point, Windows can handle remote connections.  In order to do it through the Internet you could simply forward the port 3389 from your router to the actual machine but at the same time you would expose your machine to the whole world. If you can do it, somebody else can try too.

Instead, we use a 3rd party firmware (called Tomato) on the Linksys router. This firmware allows us to connect using SSH (a secured command line shell).

With SSH we can create encrypted communication links (called Tunnels) between the laptop and the router. SSH protocol requires a server that will also open a listening port. We need to login to this server to establish the SSH connection and create tunnels.

Why this instead of just opening Remote Desktop port (3389)?

• Because we will use a *different password* (will we? well we should… and a strong one!) than the one on your computer.
• If we would have multiple computers to remote desktop to, we wouldn’t need to open additional ports, just create additional tunnels instead.
• If somebody cracks our router password, he is still limited in he can do, he has to guess/find our machine and crack its password.
• We can make SSH connection more secured by using a key file. This file is needed to establish the connection link, so another level of difficulty for a pirate…
• The communication is encrypted between the two ends of the Tunnels (more privacy)

So how to enable the SSH Server on the Tomato firmware?

Login to Tomato’s web interface Go to Administration / Admin Access In SSH Deamon section, set the following : Enable at startup: checked Remote access: checked Remote port: <choose one> (ex: 5555 — used from Internet) Port: 22 (used from inside the LAN) Authorized Keys: <empty> (for simplicity of this post) Note: Even if the screenshot shows this, we should use a different port than 22 (or 2222). If somebody discover our machine using a port scanner, he will have to guess what is the protocol (is it SSH, RDP, HTTP, FTP, etc?). If we leave the default, the guess is easy.

The home computer is enabled for remote desktop and the router is configured for SSH. Now we need to establish the SSH connection/tunnels, so put the laptop on the backpack and let’s ride to our best friend! Since the laptop is also running Windows XP, we are going to use PuTTY, an open source SSH client software (download it here).

Let’s configure PuTTY:

Start PuTTY and fill the information of the first tab: Host name or IP Address: <enter yours> Port: <the port you set earlier> (ex: 5555)

Configure tunnels in Connections / Tunnels tab: Enter a source port: <choose> (ex: 153389) Enter a destination address and port: <ip>:<port> (ex: 192.168.1.15:3389) Local: Checked Auto: Checked Click add button Note: The destination address and port is the address of our home desktop which is often in the range of 192.168.x.x depending on the router.  Our Linksys uses 192.168.1.x range by default.  IP address could be anything within the range when address is assigned by a DHCP server.  To make sure the desktop computer always have the same IP address, we can set a fixed address or configure Tomato DHCP server to always assign the same (see this post)

When we are going to open the SSH connection, PuTTY will open a local port defined by “source port”.  All the communication to that port will be encrypted and forwarded on the LAN to the destination address and port specified (ex: 192.168.1.15 port 3389).

Now let’s login to SSH Server

Click the Open button, a black screen should appear. We now have to enter the router’s username and password

The only step left is to run Remote Desktop Connection software on the laptop:

Open up remote desktop and specify the computer: localhost:<source port> (ex: localhost:153389) Click connect

Voilà  we are now controlling the home desktop from outside the house using the laptop!

Specifications of the software used in this post:

Since I may not always be on the same machine or with the same operating system when I want to run a virtual machine I bring with me, I store them on a Western Digital MyPassport USB Drive.  This drive is formatted using the NTFS file system.  I had a problem when I first tried to run one using VMWare Server on Ubuntu 8.04.  The virtual machine would not start and it didn’t gave me an error.  Fortunately I found this blog post (Lornajane) that talked about a setting to put in the vmx file of the virtual machine:

mainMem.useNamedFile=”FALSE”

This worked perfectly for me too

Hi,

I’ve been using 3rd party firmware for my Linksys WRT54GL router for some time.  I’ve used DD-WRT, OpenWRT and finally Tomato.   I switched from DD-WRT (for a reason I can’t remember) to go with OpenWRT.  I learned a lot on OpenWRT and really like their Kamikaze version.  The work they did for making it more like a standard distribution (no more NVRAM variables) is really cool.  Finally I recently moved to Tomato because of the lack of User Interface of OpenWRT (Yes I could use X-WRT but I tried it before and prefered to explore Tomato…).  When I feel lazy I prefer to use a GUI than go to the CLI…

Now that I am more familar with my WRT (thanks to OpenWRT and all its documentation), it has been pretty easy to configure Tomato (firmwares are different, but in the end, they often use the same tools… busybox, dnsmasq, etc.).  I have some specific needs that drove me to install a 3rd party firmware in the first place:

1. I need to be able to access my computers from the internet using remote desktop

2. But I don’t want to leave my computers open all day long for nothing, so I need to be able to use Wake-On-Lan to power them up remotely

3. I don’t want to open remote desktop port (3389) on the firewall

4. I want to use DHCP server, but I need to set some specific address (static DHCP) on some computers
   (so port forwarding is always configure correctly for my P2P machine…)

5. I need to be able to use the same domain name (ex: mysite.dyndns.org) with my laptop no matter if I connected to my LAN or to a public network (through the Internet)

My Solution:

General Hardware Specifications of Lenovo R61

Special Keyboard Keys

Installation Steps

The installation steps are the same that I used when I installed Ubuntu 7.10 on my Inspiron 8600

see additional configuration and conclusion on following page >>

Pages: 1 2

In this article, the analysts give recommendations Microsoft should follow to prevent collapsing of Windows. That’s interesting to see that some of their recommendations reaches some of my wishes stated in this post.

I’ve been using many Linux distributions (mainly Ubuntu) for over a year now and I’m getting more and more familiar with them. With the acquisition of a little NAS I have restructured my network and my home server. I took the opportunity to rebuild everything from scratch and now my server is running Ubuntu Server and my Windows Server is now a virtual machine. Nice but, what’s the relation with the title of the article? Well I could have done it using VMWare Server on a Windows host but I chose Ubuntu Server because its faster on my hardware. The longer Microsoft will take to answer market needs, the more irreversible market shares the competition will take. That ain’t bad since good competition brings innovation.

Another sign of Microsoft opening itself… Interesting to see that it will be easier for Java application to look more like native applications when running in Windows

Click here to read the article

Hi,

After playing a lot with multiple Linux distributions, I had hard time make my wireless card working. This was back to the release of Ubuntu 6.06. My wireless card was a Dell TrueMobile based on the Broadcom chip. Broadcom is known to not release chip specifications, so at that time, I had to use the just released open source driver built using clean-room reverse engineering, or rely on NdisWrapper to run the native Windows driver. I managed to make the open source driver work but it was painful: Needed to reconnect repetitively to get a “B” (11 mb/s) connection while my card could go “G” (54 mb/s).

Finally I got tired of all this… Since the Inspiron is using a mini-PCI card for the wireless card, I looked for a replacement card that was working well with Linux and found the Intel PRO/Wireless 2915ABG for less than 50$ CDN. After installation, it worked flawlessly!

If you are tired of you TrueMobile (or Broadcom based) wireless card and you want to replace it, here are the steps:

Oh, by the way, if you follow these steps… remember that your doing it at your own risk! First, it is suggested to ground yourself. You can use an anti-static wristband like this Belkin. Turn your Inspiron on the back and identify the battery and Wi-Fi compartment.
Turn your Inspiron on the back and identify the battery and Wi-Fi compartment. Remove the battery
Once the battery is removed and the Wi-Fi compartment is opened…
Now we need to remove the old Dell TrueMobile wireless card. Gently unplug the two antennas represented by the red circles on the picture beside. (click on the picture for a bigger display) Then press outwards on the little metal clips (blue circles on the picture) holding the wireless card in its socket and it will pop out at a 45 degree angle.
Install the new card by holding the card at a 45 degree angle and slide into the socket. Push down the card and snap it into place alongside the metal clips. Replug the two antennas (see picture beside). Screw the panel back to close the Wi-Fi compartment. Put the battery back in place. If you are using Windows, install the new drivers. For Linux, it should automatically detect it. Enjoy!