symbian 2.7.2 Memory usage Since a SIS file may be large it is not possible to load everything into memory at once.Due to the ei8e8oiamggisr98samiomionoteahsisF76i1dcambeeadwmotieadn9 2.8 Supporting the embedding of a SIS file The SIS supports the embedding of one SIS file into another.MakeSIS is able to take an already nd mbed it into a SIS file that it is d.anc ntain he files ne led for installation are added the end of the Data Units array of the sIsData sISField.Since the SIscontrollers have a Data Embedding SIS File Resultant SIs File Symbian Header Symbian Header SISController 1 SISController 1 Index-0 SISController 2 SISData 1 Index-0 Index =1 SISData 1 Embedded SIS File Symbian Header SISController 2 Index=0 SISData 2 SISData 2 Figure 1-Embedding a SIS file In the resultant SIS file.to find the absolute index of the SIsFileData in the sIsDataunit,the data indices of each of the chain of SISControllers.from the outermost SISController to the www.symbian.com5 2.7.2 Memory usage Since a SIS file may be large it is not possible to load everything into memory at once. Due to the structure of the file format, the meta-data information of each SISField can be read without reading all of the data in the contained SISFields. 2.8 Supporting the embedding of a SIS file The SIS supports the embedding of one SIS file into another. MakeSIS is able to take an already generated SIS file and embed it into a SIS file that it is creating. The existing SIS file will be loaded, and the SISController decompressed if necessary and inserted into the Embedded SIS Files field of the SISInstallBlock. The SISDataUnit which contains the files needed for installation are added onto the end of the Data Units array of the SISData SISField. Since the SISControllers have a Data Index field, which indicates the index of the SISDataUnit which contains the files they need, MakeSIS must iterate through the added SISControllers and change these to the correct values. SISController 1 SISData 1 Embedding SIS File SISController 2 SISData 2 Embedded SIS File SISData 1 SISData 2 SISController 1 SISController 2 Resultant SIS File Index = 0 Index = 0 Index = 0 Index = 1 Symbian Header Symbian Header Symbian Header Figure 1 – Embedding a SIS file In the resultant SIS file, to find the absolute index of the SISFileData in the SISDataUnit, the data indices of each of the chain of SISControllers, from the outermost SISController to the