Structural and functional test of IBM System z10 chips

For the first time in the history of the IBM System z™ family of
mainframes, System z10™ processor chips are tested by both
structural and functional means. This complementary strategy
starts at wafer test and is consistent through system test. In this
paper, we describe how traditional and enhanced structured
patterns provide fault coverage and how functional patterns mimic
real system workloads. A new operating kernel generates
functional tests and expected results and it can run these tests for
either a finite or an indefinite amount of time to simulate system
operation. It also executes custom hand-loop patterns to stress chip
temperature and power. Both structural and functional patterns are
used to uniquely characterize each chip. Adaptive algorithms based
on results at wafer test determine optimal system operating voltage
for each chip—a strategy that delivers a chip supply with optimal
characteristics for system manufacturing and product delivery. The
diversity of structural and functional patterns makes it possible to
increase z10™ chip quality and reduce development time. The
ability to run the same tests from wafer through system test
provides a consistency not previously possible.