Tao of the Windows Installer, Part 1

Ever agreed to something you thought was a quick favour, just to see it balloon into a massive project?

Well, towards the end of last year a customer asked me for a list of "best practices" for the Installer. Being helpful, I agreed to send one and started looking for a list. Now, as the Installer was released last millenium, I assumed that someone would have created such a list by now and my search would be short. How wrong I was.

After much hunting, I couldn't find any document solely devoted to Installer best practices. Sure, there are recommendations and advice scattered around various sources - from my own experience and that of other Installer users in Microsoft to white papers and the SDK - but nothing dedicated to giving straight advice on what to do and what not to do with the Installer.

Having agreed to provide the list, I had to get one somewhere, so I decided to create my own from the many individual bits and pieces I gathered in my search. This is where things just seemed to take on a life of their own. I had envisioned a short (1-2 page) list, but some months later ended up with a 30+ page document!

Once I had this in reasonable shape, someone pointed out that it would probably be useful to the whole Installer community and not just one customer. So here it is - or at least here is the first part.

I initially looked into publishing the list as a white paper for download from the Microsoft web site. Unfortunately, the process of editing and reviewing white papers can take a while, so I decided to post here on the Installer blog first. Mainly so that the information can be made available quicker, but also just as importantly, so you can give some feedback to help improve the final white paper.

The paper is currently divided into various section, including a brief description of Installer functionality, troubleshooting advice, etc. However, the bulk of it is a series of "rules" (that is, the "best practices"), split into the following subtopics:

This week, I'll cover the short Fundamentals section, with the other sections following on an approximately weekly schedule. Feel free to point out the good, bad and ugly in the list - your feedback will make sure that the final whitepaper will be as accurate and as useful as possible.

Fundamentals Rule 1: Learn the Windows Installer Technology
The importance of this rule cannot be overstated. If you only follow one rule, this is the one to choose. Microsoft Product Support often speak to Installer users who are installing packages which they created with a sophisticated high-level re-packaging tool, without any understanding of how the Installer actually works. While these tools are excellent at what they do and they abstract the user from the details on a day-to-day basis, the lack of Installer knowledge becomes a real problem when the package does not work as expected. Setup authoring is not simply about copying files. The Installer offers extensive functionality and complexity; understand it before you start authoring packages. Start with this guide, then read the white papers, books, etc mentioned in the Resources section, then follow Rule 2.
Rule 2: Know Your Way Around the Installer SDK
The best resource to help with Rule 1 is the Windows Installer SDK (usually just called “the SDK”). It is the definitive guide to the Installer technology and covers all aspects of creating packages, including detailed descriptions of database tables, properties, custom actions, etc. The SDK is designed as a reference and so you shouldn’t try to read it from start to finish. However, it does contain many tutorials and specific examples you may want to follow and try out for yourself. In any case, you should make yourself familiar with its contents and use it as your first port of call when you need to know something about the Installer.
Rule 3: Use the “Windows Logo” Program as a Basis For Good Practices

The "Designed for Windows XP" Logo Program is designed to help give users confidence in the software and hardware they buy to work with Windows. The logo ensures that any software conforms to a Microsoft-defined set of criteria that are designed to provide a consistent, high quality software experience. So, even if you do not intend to submit your application to the logo program, you can still use the guidelines to help make your Installer packages better. Many of the logo requirements for software are covered if you use the Installer as your installation mechanism. Some of these rules are shown below, with more details available on the logo program website.

  • Do not attempt to replace files that are protected by Windows File Protection
  • Migrate from earlier versions of Windows
  • Do not overwrite non-proprietary files with older versions
  • Do not require a reboot inappropriately
  • Install to Program Files by default
  • Install any shared files that are not side-by-side to the correct locations
  • Support Add or Remove Programs properly
  • Support “All Users” installs
  • Support Autorun for CDs and DVDs
Rule 4: Always Use the Latest Version of the Installer

Using the latest version of the Installer gives three important benefits:

  • Extra features. Version 3.1 is the Installer version at the time of writing. This contains many new and enhanced features over earlier editions. In particular, from version 3.0 of the Installer, patching and patch management was greatly improved.
  • Bug fixes. Using the latest code, and keeping this patched with current updates from Microsoft Update, ensures that you are more secure and will avoid known problems.
  • Support. Microsoft does not support or issue bugfixes for older Installer versions, such as v1.1. Always using the latest version means that Microsoft Product Support will be able to assist with problems and supply updates and patches.
Rule 5: Build Setup Into Your Application Development from the Start

Installation absolutely should not be an afterthought in the development process. Many developers don’t like the idea that “setup” should influence the design of a product, but when using the Installer it is crucial to develop the two in parallel. Thinking up-front about how an application will be installed makes it easier to take advantage of the idea of “features”, “self-repair”, etc. So, rather than forcing the software into some artificial split or limiting very large applications to a single feature, you will end up with a more user-friendly and resilient install. Remember that:

  • The developer writing the code knows better on what, how and where the configuration data for thier application/module should be
  • It is better to grow the stability and confidence of the product setup along with the confidence in the product itself: a poor product setup will leave lasting bitterness with the user
Rule 6: Get to Know ORCA
ORCA is an MSI package editing tool that ships with the Installer SDK. It has a basic GUI interface but supports advanced editing of Installer Databases. It is possible to create a new package completely with ORCA, but this would be very tedious and error prone; equivalent to writing the Microsoft.com website in Notepad - possible, but not something you’d really want to do. Where ORCA excels is in letting you quickly view and edit package contents for troubleshooting and testing. This reason alone should be enough reason to become familiar with using ORCA, but it also provides a convenient way to validate your packages - a vital step during package creation and testing.

[Author: Richard Macdonald]

This posting is provided "AS IS" with no warranties, and confers no rights.