Windows Installer FAQ – Part 2


As you guys are aware, I am writing a series of posts which covers some key discussions, topics and FAQs in the stream of application packaging. In this second post, we will look at some questions, which involve deployment privileges and types of Installations.

Q6. What is a MSI product made up of?
A package contains everything that the windows installer service needs to install a particular product. This includes the appropriate MSI files and any external files(such as CAB files) that the setup needs. Packages, too, are identified by GUIDs. If you make any change to a package, you must assign a new package code.

A feature is a piece of functionality that makes sense to the end user of the software. The help system could be a feature, or spell-checking, or wizards. If you have ever installed software that displays a tree view of things that you can choose to install or leave out, those are individual features. Features are identified by strings that must be unique within a particular package.

A component is a unit of software that the installer can install. Components can include files, registry keys, shortcuts, resources, and other things. Each component is identified by a GUID, the component ID, which must be unique across all packages, regardless of product.

Q7. What are the Different types of Privileges during the installations can be given?

Locked-down
• The users doesn’t have the full admin rights to install the application
• The users doesn’t have WRITE-ACCESS to the Program Files folder of their computers or to the HKEY_LOCAL_MACHINE registry location
• Installation can be done in this environment by the approval of the Administrator by means of GPO or Active directories, the administrator can assign or publish the application.
Elevated rights
• An account or process that is operating or logged into the computer that has full administrator rights or permissions.(User can install the application but doesn’t have rights to set Group policies ).
Administrative Rights
• Highest level of permissions that can be granted to an account in Windows NT User Manager. An administrator can set permissions for other users and create groups and accounts within the domain. These rights are required to install the System Files Update.

Q8. What are the Functions and capabilities MSI has?
These are the following functions which an MSI provides,
• Transactional Operations: For each operation that an MSI performs It can undo and rollback hence System will not contain unwanted FILES /Registries and will be more clean if uninstallation fails.
• Self Healing: MSI can detect common installation problems at launch, like missing Files and Registries and automatically repairs them.
• Install On Demand: It supports on demand installation of application features { like Spell Check in Words}
• Installation On Locked Down Environments (this is done using Elevated Privilages also)
• State Management: Windows installer provides a set of WiN32 API which allows querying the current state, verification of the existing state, repair of corrupted state and transition from one state to another.
• Consistent Installation Rules: Windows Installer uses consistent and reliable version rules, which provide consistent and reliable installations for all applications and prevent newer files from being overwritten by older files.

Q9. How advertised installation (on demand Installation) is different from a normal installation?
An advertisement installation places entry points, such as shortcuts, on the destination computer without actually installing the application. When an installation is opened in advertising mode, only the Execute sequences are run because it does not have a User Interface sequence, and therefore no dialogs appear
Command line /JU (User) and /JM (machine) is used for that.

Q10. Should users with user-level privileges be able to install MSI applications?
A user with user-level privileges can install managed applications if the system administrator has enabled the installation. Otherwise, the user will only be able to install MSI applications provided the user has permission to write files, create directories, and write registry keys in the locations where the installation typically writes those resources. If the user cannot write to a location, then the installer will only be able to write to that location if the administrator has given permission for the installer to do so.

I would recommend, You read the other parts too – Part 1 , Part 2 , Part 3 , Part 4, Part 5 (Coming Soon)