Software installer
End users can install new software from a variety of sources: through e-mail, Internet downloads, multimedia messaging service (MMS) and WAP push messages, infrared and Bluetooth connections, PC Suite, and removable memory cards. The diversity of software vendors and delivery channels requires a sophisticated system for managing installed software.
The Symbian Software Installer uses digital signatures and certificates to authenticate that the application being installed on a mobile device is from a known vendor. The signature can be obtained through the Symbian Signed process, and the default certificates installed in the mobile device act as root certificates. During installation the signature is validated against the certificates. If they match, the application is installed and the requested capabilities are stored in the executable, assuming that the root certificate can grant the capabilities. Only user capabilities can be granted to unsigned or self-signed applications, and these are always confirmed by the user.
Note: The end users have an option to cancel the installation if they detect that the vendor of the software package and certificate authority are not trustworthy. This is especially important when installing security-related components (for example, VPN clients, firewalls and virus scanners) or other business-related software.
The Software Installer ensures that no two applications have the same SID value
on a particular target device. The Software Installer has the TCB capability
to read and modify content in the \sys folder
and all its subfolders, which means that you can write to third-party application
executables in the \sys\bin folder when they are installed
through the Software Installer.
For more information on the Software Installer, see Software Installation Toolkit in the Symbian OS Library.
The following figure illustrates the steps of software installation:
Figure: Installation process for signed packages
The Software Installer can install two types of packages: signed sis packages,
and Java archives (JAR) run by a Java virtual machine. S60 3rd Edition, Feature
Pack 2 introduced the ability to install web widgets. It is also able to recognize
different devices, allowing you to define the platforms and devices to which
the software can be installed.
Software can be installed to or from removable media. For more information, see How to install to/via a media card in the Symbian OS Library.
If you receive an error message when using the Software Installer, see S60 SW installer troubleshooting in the Forum Nokia Developer Community Wiki.