Adventures of a Setup Developer

I have moved back to blogger. Please update your subscriptions. Inconvenience regretted. :-) Wish you all a very happy and prosperous new year.

This post is for all the indians both in India and abroad who crib about the situations there. These two clips show more than what I would like to say. It is time for all of us to accept this progress and enjoy it. Yes, we do have our problems. We still have incidents of communal riots. We are still bombed by terrorists. Much of Rural India is still to get the taste of this improvement. But we are living in an age with comforts that our previous generation could have only dreamed of. So be happy about it and do your part in making it better.

India before
http://www.youtube.com/watch?v=mKJSDYvxHzw&mode=related&search=

India Now
http://www.youtube.com/watch?v=Y_j-N3QkaVE

Happy Diwali and Id Mubarak. Jai hind.

It is bound to happen. You will have a developer come up to you one day and say, "Remember the DLL file that we shipped in the previous release, we have consolidated its functionality into the core library. We need to remove that library in the latest release." You as a Windows Installer developer would then be frustrated after finding out that you cannot remove components during a minor upgrade and you will have to manage with all the ugliness of a major upgrade.  I will write about the ugliness of a major upgrade in some other blog.

So if you really have to remove the DLL, you need not have to go through the trouble of major upgrade. We can actually uninstall components during a minor upgrade. But the catch is that you should not remove the component from the existing MSI. My colleague Kajal Biswas calls this process as "Puncturing the component". Let me detail the process of puncturing the component.

1. Consider the component abc.dll which has to be removed. 
2. Collect the Registry, CLSID and the COM information if you have dynamically acquired them, you will have to fill them in manually later. This is usually the reason why I do not use COM Extract at Build. I usually use 'Extract COM Information' feature of InstallShield DevStudio. This would ensure that I can find out the exact registry entries and COM Settings.  If you had used the WiX Toolset, it is pretty straight forward. You will just have to go to the next step and you can ignore this completely.
3. Replace abc.dll file with a zero byte file with the same name.
4. Set the transitive bit of the component. If you are using InstallShield DevStudio, simply set the 'Reevaluate Condition' field in the component property to 'Yes'. 
5. Replace any existing condition on the component with a condition that evaluates to false. As a habit, I and my colleagues enter the paradoxical '1=0' as the component condition. You can also enter something meaningful like 'GoToHell=666' or something like that.

During a minor upgrade, if the feature associated with the component is reinstalled, the trasitive bit with also force the state of the component to be reevaluated. And since the component is present and the condition is false, the component will be uninstalled during a minor upgrade. It is hack. But it works.

Windows Installer's transitive bit is a really cool thing. It allows you to author your components in such a way that it would install if component's condition is true and uninstall if it is false even during upgrades. Well almost. Refer the documentation for more information. So this can be used to get rid of pesky components that you need to uninstall during a minor upgrade. Now we thought this stuff was really neat and applied it to all the components. We had our justifications that this setup will always be done by admins and will always be per machine. None of the components wrote anything off to HKEY_CURRENT_USER and we were pretty much safe in assuming that it would not be the case in the future either. So we turned on the transitive bit for all our components. The software behaved exceptionally well. The maintenance was driven via a external wrapper which always passed the REINSTALL parameter and hence everything worked very well.

This allowed our MSI to behave as a state machine. You could simply throw in a bunch of properties and set its state and it would just install the ones that are required. This basically solves the problem of setup types and you do not have to write custom actions to set the feature request states.

We had tested most of the scenarios on different operating systems and it seemed to function just fine. We had it going through the last round of validation when we got a call from one of the landscape administrators that the product had uninstalled itself. Windows Installer had triggered a repair after the application of a hotfix by one of the developers and had completely uninstalled the application. The reason being that the Windows Installer repair operation also re-evaluates the component conditions and decides that they should not exist on the machine. The problem rested in the fact that even though we did persist the properties to be retrieved later, but that was entirely upto the bootstrapper to do it as the bootstrapper was the single entity that would do all the MSI related maintenance activities. So when the MSI repair started, which of course is as good as a quick reinstall, it ran through the entire InstallExecuteSequence table and found that most of the components were not supposed to be on the machine and had them removed. The solution was fairly simple. We had to persist all the properties and its values in the registry and we had to author AppSearch entries for all the properties and do a sort of quick check for the settings and swap the values with the actual ones during such a repair operation.

So if you plan to use the MSI transitive bit for your components, be very careful. You have been warned.

I was recently working with Reflection and Boo and thought this was funny. Hey.. nobody told life is simple right. So, here it goes. :-)

i as int
i=i.GetType().GetMethod("Parse",[typeof(string)].ToArray(typeof(System.Type))).Invoke(null,["42"].ToArray())
print "Answer to the question of life, universe and everything is ", i

The new GPLv3 draft has been posted for discussion. The Rationale Document explains the changes.

I found this flash presentation while I was browsing the web today. It was Lawrence Lessig's address at OSCON 2002. An extremely interesting presentation.

I came across an interesting site to create SouthPark style cartoon characters. If I had been a SouthPark character, I would have probably have looked like this.

I have lately been pondering over methods to deploy cross platform products. I investigated certain options like InstallShield's Universal Project and ZeroG's InstallAnywhere. But to tell the truth, it goes against the philosophy of installation. They rely on the presence of the right version of JRE. Some installations also package the native versions of JRE along with the installation package. This is quite an overhead. Other products use their custom homegrown installers. As most of the setup developers and administrators know, homegrown installers are a disaster waiting to happen. A good installation technology should do the following.

• Installation - This is the easy part.
• Rollback in case of failure
• Support for dependency and conflict resolution.
• Support for transactional install/uninstall operations. This is very important for the integrity of the system.
• Support for upgrades.
• Heal installed applications.

Creating a custom installation technology with all these features is difficult if not impossible. Also it is an investment that is not required when you can reuse the wheel. Each of the operating systems or the platform targeted have a native installation technology which support all of the above points in some way or the other. Most of these cross platform applications are deployed on Windows, Linux or Solaris. Windows has the Windows Installer a.k.a MSI package format to keep an inventory of software that is installed in an extremely fine granular level. Linux has RPM and DEB formats which deal with packages at a more coarse scale than Windows Installer but have excellent dependency and conflict resolution. Solaris has its native PKG format to install packages.

So instead of a cross-platform installation program, we could have a cross platform tool to create multiple installation packages for multiple platforms. One of the biggest problems working in this direction would be that the setup engineer should have a knowledge of all the platforms that he is packing the application for. This is usually not a easy job. For instance, I could handle Windows MSI and Linux's RPM & DEB files but would be a completely lost on a Solaris platform.

The biggest challenge would also be the fact that the customization scripts and custom actions would need to be coded by the setup engineer for each platform or package format. But this is a small price to pay for the amount of flexibility that can be achieved. The software deployment becomes a breeze and would significantly lower the (holy grail of three letter acronyms) TCO.

There exists a lot of literature written on Free and Liberal Open Source Software(GNU/FSF). This is what I feel about it. I had recently been to a school to give an introduction about computers to some kids in a village near Pondicherry. I had access to a laptop and showed them a quick presentation on the basics of computers. I was aware of the fact that the school syllabus has Microsoft Windows as the primary platform for education. Most kids think paint is cool. What would they say if they saw GIMP? But the government has to realize that providing a computer and upgrading the license of the operating system is a costly business. Most of the schools in India run on a shoe string budget. Let us do the math now.

Number of students for a class (at least)	30
Number of client licenses to be purchased if the computer is shared by 3 users	10
Cost of a computer (approx)	Rs. 10,000/-
Cost of a Microsoft Windows client license (approx)	Rs. 2,500/-
Cost of a Microsoft Windows Server range operating system	Rs. 40,000/-
Total cost for client operating system licenses	Rs. 25,000/-
Total cost of the workstations (hardware)	Rs. 1,00,000/-
Cost of the server hardware (basic p4 based desktop to act as a database server/Web Server)	Rs. 30,000/-
Total cost of setting up 10 terminals with 1 server	Rs. 1,95,000/-

I have not included the cost of buying software like Microsoft Visual Studio .NET 2003 and Microsoft SQL Server, which would each cost about 35,000 and 45,000 approximately. Please let me know if my figures are wrong. And the SQL Server is for 45,000 is only a standard 5-client edition. Also there exists a problem with upgrades. You would have to pay for them too. You would need to get two licenses which would mean a catastrophic cost for a simple school to setup. The common solution that various schools adopt is to pirate the software. This is much more rampant in the schools in the private sector. A crackdown on such schools would put most of the schools out of business. The moment you open a new school/college you open up a software piracy den and promote criminals. Let us look at the figures for Linux.

Number of students for a class (at least)	30
Number of client licenses to be purchased if the computer is shared by 3 users	10
Cost of a computer (approx)	Rs. 10,000/-
Cost of a Microsoft Windows client license (approx)	Rs. 0/-
Cost of a Microsoft Windows Server range operating system	Rs. 0/-
Total cost for client operating system licenses	Rs. 0/-
Total cost of the workstations (hardware)	Rs. 1,00,000/-
Cost of the server hardware (basic p4 based desktop to act as a database server/Web Server)	Rs. 30,000/-
Total cost of setting up 10 terminals with 1 server	Rs. 1,30,000/-

As it is clearly seen, it is important for all the schools in India to adopt Free and Liberal Open Source Software. This step would mean the following advantages for the Indian society.

1. The cost of setting up new computer labs is significantly lowered.
2. Students will gain the ability to produce software on open source platforms.
3. Projects targetted at open source platform can serve the Indian Society.
4. This will free the small businesses from the requirement of purchasing pricey software. They could use open source software built by our future software professionals.
5. Open Source Software engineers in my belief have a better understanding of the underlying technology and can really benefit from the community.

Necessity is the mother of invention. As more and more people adopt open source software, I am sure that they in turn will create a need for better software. I have been using Linux on and off for the past several years and have seen it progress in leaps and bounds. I would strongly suggest open source operating systems like FreeBSD or Linux as the operating systems. They have a host of open source products to suffice every need in the closed source world. I do agree that there are open source products available in the closed source platform that are on par with their commercial counterparts. For example, SharpDevelop would suffice the need of any normal C# programmer who has not been pampered with Visual Studio .NET 2003 features. But on the other hand you have Eclipse which would seem VS.NET 2003 seem like a baby. MySQL competes with Microsoft SQL Server in the DB Server arena. PHP can serve as a commendable alternative to ASP and ASP.NET. Apache Web Server gives IIS a run for their money in the Web Server segment. Java and Mono provide solid cross platform application frameworks. Even though Java is not strictly open source, its free availability on open source platform makes it a lucrative option. Apart for these compilable languages, Python and Ruby offer a quick application development cycle which is ideal for developing small business tools.

It is now time for the educational institutions in India to decide if they still want to pay a huge sum or indulge in criminal practices to learn/teach software or adopt the clean and relatively hassle free path of Open Source software to produce better software engineers.

After a hectic schedule, I decided to give myself a break. So I decided that I will install Linux just for fun to refresh my memory on the linux front. It is also a small bet with my colleague that I could be productive and have fun with Linux just the way I work with Windows. I was arguing on the fact that there is no better learning platform than Linux. I've worked only on RedHat 7,8,9 distros that are distributed with magazines. There is this old joke about Open Source communities vs. Closed source vendors . It goes something like this. "Commercial vendors sell software but give away free T-Shirts. Open source communities give free software but sell T-Shirts."

So, here I am blogging from my linux (yeah!!!) machine. It has been a long time since I had worked on any of the linux distros. I tried downloading Fedora, but it was just too big. So is Novell Desktop Linux. I've got the bandwidth and everything but shelling so much space for it from my hard disk did not seem worth it. Who needs so much stuff anyway. So I settled for Ubuntu. Ubuntu still retains the open source passion that makes it attractive. The installation was lightweight and text based which suits me. I do not want any fancy graphics for the installation. Ubuntu installed GNOME by default and to my surprise had disabled the root account. I first felt a little uncomfortable running as a non-privileged user. We've all got used to running as administrator on our windows machines. People would laugh if you said you did not have administrative privileges on a Windows Machine. But on a linux machine it is normal that you are a restricted user. Everytime I used Nautilus to copy files I was reminded that I was running under a non-privileged user login. Although I could launch Nautilus itself with sudo, I used the command line. I still remembered basic linux commands. That was quite a relief.

Unfortunately, I was not able to listen to LaunchCast and I miss my MSN Radio already. :-( Apart from that I am pretty happy with the distribution. It seems to be pretty stable. I have installed (rather extracted) Eclipse, the latest Java Runtime and the pydev Eclipse plugin. It is a pretty neat. If time permits, I will try to write a small sudoku puzzle solver in Python on my Linux machine. And finally, just for the pure visual treat and to prove that everything is working, here is the screenshot of my desktop.

 While I was browsing the MSDN, I came across this very interesting video which features Anders Helsberg and his skills with the whiteboard. I really wish that he teach me programming. A must see for every C# programmer.

This morning I was working on something and my mind kept wandering. So I just went blog browsing and I saw the link to a nerd quiz. Not finding anything better to do, I took it. Here is the score.

 

Guess, I am not that nerdy after all. Okay, time to get back to work. <SMILE />

• InstallUtilLib.DLL is not completely silent. It still pops up an ugly message box with it fails.
• The methods do not have access to the MSI thread. So we would not be able to use properties or write to the MSI log file.