Practical software reuse for IBM System z I/O subsystems

The design and implementation of the z/VM® SCSI (Small Computer System Interface) I/O subsystem is described. z/VM is an operating system that provides multiple virtual IBM System z™ machines on a single IBM System z computer. The approach adopted herein allows the reuse of entire device drivers from AIX 5L™, a completely different operating system, essentially unchanged. AIX 5L is the IBM UNIX® operating system for the IBM System p™ platform. The design, and much of the implemented code that allows the incorporation of such “foreign” device drivers, is independent of both z/VM and AIX 5L and could potentially be used in other operating system environments.