the full name of SIS is SymbianOSInstallSystem, which is used to judge the system version, decompress compressed files such as exe, rsc, MIF, etc., and perform crc verification. This is the SIS function of S6v1 and v2. In S6v3, SIS has become a SecurityChecker. In addition to the above functions, You should also check the electronic signature, including the permissions allowed in the signature, and check in detail whether each API call conforms to the permissions in the signature. If any of them do not conform, you can't install it. Symbian calls the new SIS SIXX, with x = extended extension. If you open a SIS without a SecurityModel on OS9.1, you will be prompted that installation is not supported.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * It can be seen that the file extension is just a code name, and the key lies in the encapsulation mechanism. This is why some SIS programs can also be installed. Generally speaking, the significance of adding such strict verification means to S6V3 lies in preventing piracy and malicious programs (viruses).

At present, there are not many softwares based on the third edition, but there is good news. NOKIA officially promises to launch a SIXX packaging tool in the future, which can convert the existing sis software into SIXX.

hey, I'm looking forward to it.