How the Z13 named for Z13 Mainframe?

The z13 is so named because it’s the 13th generation of CMOS mainframe.

What is CMOS?

For the mainframe, and the whole computer industry,
it’s been a great ride on complementary metal-oxide semiconductor (CMOS) technology.

Mainframe Infrastructure got drastically reduced during mid 1990.
Yes. That was the time, CMOS Technology got introduced.
It replaced the older technology - Biploar.



IBM claimed that its newer mainframes could reduce data center energy costs for power and cooling, and that they could reduce physical space requirements compared to server farms.

The CMOS mainframes also started with a relatively simple processor design and evolved into a sophisticated RISC-like processor, capable of very efficient execution of the rich and complex z/Architecture.

Many of the improvements in processor design were actually a redeployment of design ideas that had been developed for the bipolar processors that preceded the CMOS-based systems. These include techniques like:

• Superscalar parallelism
• Advanced branch prediction
• High-frequency pipelines, and
• Out-of-order instruction execution

Some of these techniques have had further innovation, like more sophisticated branch-prediction algorithms.

Also, practices have been introduced allowing a RISC-like instruction processor design despite z/Architecture being a complex instruction set architecture.

One interesting technique that enabled this is called instruction “cracking,” whereby complex instructions are decomposed into simpler instructions so they can be efficiently executed on a very high-frequency processor. 

• The first Mainframe with CMOS, IBM 9672 R11 was introduced in 1994 and rated at about 15 MIPS. It was in S/390 Operating system.
• In October 2000, Z series, Z-Architecture got introduced. OS/390 got converted into Z/OS operating system.
• In 2012, zEnterprise EC12 (zEC12) mainframe got introduced and rated at about 1,500 MIPS. That’s a 100-fold increase over about 18 years.

The combination of silicon technology improvements and design advances has led to the explosive growth in CMOS processing power, culminating with the zEC12 and its processor speed of more than 1,500 MIPS.