SAP Kernel is the core of the application. Like all other applications the Kernel contains the executable files (.EXE files for stating various processes in SAP.
Thats th ereason why when a Kernel upgrade is done it means new versions of the various EXE files replace the older versions.
With regards to advantages, it is an appropriate question in this context since the Kernel is a must (.EXE)
Kernel is the heart of operating system. It contains those files which are used to run every event in SAP. ex: starting database, shutdowns of database, starting sap, shutdown of sap, saposcol, to uncar the sap files etc......iat contains more than 120 exe files.
The steps to do kernel upgrade are listed below.
1) Execute the command disp+work -v to get the present kernel version
2) Check with the T Code SM51 to Check the R/3 SYSTEM->STATUS to get the present kernel level
3) Download the latest kernel patch from SMP
There are 2 files to be downloaded from SMP:
a) Database Independent Files
This is of the nomenclature SAPEXE_<Patch level>-<release date>.SAR
b) Database Dependent files
This is of the nomenclature SAPEXEDB_<Patch level>-<release date>.SAR
4) Uncar the .SAR files
Uncar the files using the SAPCAR utility and store it in a directory. SAPCAR is a program executable located in the KERNEL folder itself. If SAPCAR is not working, then copy the executable from the kernel folder to the location where the .SAR files are located.
SAPCAR -xvf <filename.SAR>
5) Stop the J2EE Engine and the SAP OS Collector
SAPOSCOL service should be stopped because it also will get overwritten by the new file.
6) Backup the present Kernel directory
Copy the present kernel folder safely. This is important because the activity is completely reversible and switching over to the old kernel will be possible.
7) Copy the new kernel files to the RUN folder location
Copy the files in such a manner that the RUN folder is overwritten by the new files.
cp -R <source file > <destination>
8) Check the permissions of the files in the kernel directory
chown [-R] newowner filenames
chmod <1>permissions filename
9) Start the J2EE Engine and the SAP OS Collector
10) Check the latest Kernel level
Execute the command disp+work -v to get the new kernel level.