“If you had any doubt of IBM’s commitment to Linux on its
mainframe servers, Tuesday’s announcement of the new eServer z900
platform should put those doubts to rest. The zSeries is the
top end of IBM’s newly-named eServer product line, and it replaces
all existing System/390 processors. The eServer label is being
applied to some of IBM’s already-released hardware, so for some
products today’s announcement is mostly a rebranding. At the
mainframe end, the z900 represents a totally new hardware
architecture — and IBM is pushing Linux as a core product to run
on it.”
“Although IBM claims full backward compatibility with all
System/390 software, the z900 is a significant upgrade in
performance as well as a demonstration of IBM’s semiconductor
prowess. The CPU is built onto a multi-layered ceramic substrate
and each multichip module (MCM) contains up to 16 CPUs. There are
about 31 integrated circuits inside the MCM and they are connected
to one another and to the module’s external I/O bus by over 1000
meters of gold wire. The transistor tally on the MCM’s ICs tops 2.5
billion, so each of those 31 chips inside is significantly complex
in its own right. The whole thing is about 12.5 centimeters square.
The raw cycle time of the processor unit is specified at 1.3
nanoseconds, and general-purpose registers are 64-bit length as is
the memory address bus.”
“IBM claims approximately a 20-30 percent performance increase
per processor over their S/390 “G6 model Z17″ machine. In addition,
the maximum number of CPUs per system has increased from twelve on
the S/390 to sixteen on the z900. The math works out to about 70
percent faster at the top end of the z900, compared to the top end
of the S/390. Of course, benchmarks like these are pretty synthetic
and a lot depends on the operating system and the applications. In
fact, IBM is claiming only 50-60 percent increase for the z900.
Another aspect of performance is the system’s ability to offload
processing to specialized coprocessors, and here the z900 gains
another edge….”