Appendix F. Porting Issues Specific to the IBM zSeries Mainframe

In this appendix

F.1	Linux on IBM zSeries	page 664
F.2	Data Types, Addresses, and Machine Words	page 665
F.3	Compiling and Linking	page 668
F.4	Byte Ordering	page 672
F.5	Other Differences	page 673
F.6	Variable Argument Lists	page 674
F.7	Where to Find More Information	page 674
F.8	Acknowledgments	page 674

Contributed by Wolfgang Gellerich, IBM

Fortunately, there are rather few specific issues to be considered when porting application programs to Linux running on an IBM zSeries mainframe, because the "official" interfaces of the Linux kernel are platform-independent. One important difference, however, concerns the way the Linux system itself executes on a mainframe. Personal computers usually run a native operating system controlling the whole computer system. In contrast, IBM zSeries systems support the concept of virtualization. Any operating system within the zSeries platform executes in a virtual environment, and there may be (and normally are) several instances of several different operating systems running at the same time.