MSI provides a host of advantages over other installation programs which include but are not limited to:
1. Repair Damaged Installations
At times a clean installation can turn bad owing to a missing file or accidental deletion of some files from the applications folder. This could be due to an error on the user’s part, corrupt files, disk crashes, etc. When run in maintenance mode, MSI based installations provide a “Repair” Mode which allows user to repair their existing applications without bothering to uninstall / re-install the whole application. MSI installer replaces any missing or corrupt files from the files installed on the user’s machine and the system is ready for use. The Windows Installers service identifies the missing or corrupt files from the users system and replaces them from the source media or Network Image.
2. Easy Management of upgrades / patches
MSI supports creation of updates or patches and has an in-built functionality to implement the rules for applying patches on the user’s machine. With the help of its inbuilt version field, the developers need not worry about writing rules for the patch installations.
3. Ability to provide Roll Back in case of a failed installation
This is in all probability the biggest advantage of MSI over other setup types. One of the trickiest things to handle during installations is a state when the half way through the installation needs to be aborted for one or more of the reasons listed below
• The user cancels the installation
• There is an irrecoverable error
• Changes to the state of the system by another application
This often leads to a dirty installation. From the users’ perspective, they would prefer to have their state back as it was prior to commencement of installations. Implementing a complete Roll Back was never a good option with traditional installer software’s owing to time consuming procedures and managing various states of files.
With MSI the Roll Back functionality is in-built and is ready to use out of the box. If the user cancels or aborts the installation in between, the Windows Installer restores the user’s machine to the state it was before the installation started. It restores any deleted files, removes any registry entries done, deletes any folders the installer might have created, etc.
4. If enabled, extensive logging enables easy debugging
With Installations becoming more complex and increased demand for support for installations over the network, it becomes difficult to handle a broken installation package. MSI by default provides logging features which help in providing meaningful information to the users in case of failed installations. The developers need not write additional code to log messages; the logging engine is intrinsic to the MSI Installer and logs each action from the sequence.
5. Ability to customize installations with Transforms
Transforms are additional files that can be associated with the MSI installers to customize the installations. As an example if the installation is to be repeated over several workstations in a Lab, a transform can help in installing the product with a pre-determined set of settings on one machine and replicate the same across all other machines in the Lab.
6. Ability to do a silent installation without any user intervention
In addition to the transforms, MSI can be used to author silent installations with ‘Zero’ user interaction. The installers can read the parameters from a configuration file and complete the installation.
7. Permissions and rights management
In case of traditional installers the installation is run in the context of the user who has logged into the system. This brings up a challenge of handling user permissions and security settings. In case of MSI Installers, the Windows Installer runs as a system service and hence there are fewer issues with respect to security.
8. Network Deployment using Group Policy
When used with Active Directory, an MSI can be associated with a group policy to let end users install the application on their systems even if they don't have rights to modify the file system or registry. The request is passed on to WIS (Windows Installer Service) for the actual install.
No comments:
Post a Comment