This overview paper describes the key steps taken by IBM to transform
the S/390(R) mainframe platform and to enhance customer satisfaction w
ith improvements in cost, scalability, and application enablement, The
effectiveness of the transformation is discussed in the context of pe
rformance and reliability, and the significance of cluster architectur
e is defined, Finally, mainframe resurgence is discussed, and factors
important to enabling the growth of servers and microprocessors are pr
esented.