6947ch02.fm

Draft Document for Review April 7, 2004 6:15 pm

2.1 System structure

The z990 structure and design are the result of the continuous evolution of S/390 and zSeries since CMOS servers were introduced in 1994. The structure and design have been continuously improved, adding more capacity, performance, functionality, and connectivity.

The objective of z990 system structure and design is to offer a flexible infrastructure to accommodate a wide range of operating systems and applications, whether they be traditional or emerging e-business applications based on WebSphere, Java, and Linux, for integration and deployment in heterogeneous business solutions.

For that purpose, the z990 introduces a superscalar microprocessor architecture, improving uniprocessor performance and providing an increase in the number of usable processors per system. In order to keep a balanced system, the I/O bandwidth and available memory sizes have been increased accordingly.

2.1.1 Book concept

The z990 Central Processor Complex (CPC) introduces a packaging concept based on books. A book contains processors (PUs), memory, and connectors to I/O cages and ICB-4 links. Books are located in the CEC cage in Frame A. A z990 server (CPC) has at least one book, but may have up to four books installed.

A book and its components is shown in Figure 2-1. Each book contains:

￿12 processor units (PUs). The PUs reside on microprocessor chips located on a Multi-Chip Module (MCM).

￿16 GB to 64 GB physical memory. There are always two memory cards, each containing 8, 16, or 32 GB.

￿Three Memory Bus Adapters (MBAs), supporting up to 12 Self-Timed Interconnects (STIs) to the I/O cages and/or ICB-4 channels.

MCM

STI Slots

Memory cards

Figure 2-1 Book structure and components

Up to four books can reside in the CEC cage. Books plug into cards, which plug into slots of the CEC cage board.

24IBM eServer zSeries 990 Technical Guide

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IBM 990 manual System structure, Book concept
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990 specifications

The IBM 990 series, often referred to in the context of IBM's pioneering efforts in the realm of mainframe computing, represents a unique chapter in the history of information technology. Introduced in the late 1960s, the IBM 990 series was designed as a powerful tool for enterprise-level data processing and scientific calculations, showcasing the company's commitment to advancing computing capabilities.

One of the main features of the IBM 990 was its architecture, which was built to support a wide range of applications, from business processing to complex scientific computations. The system employed a 32-bit word length, which was advanced for its time, allowing for more flexible and efficient data handling. CPUs in the IBM 990 series supported multiple instructions per cycle, which contributed significantly to the overall efficiency and processing power of the machines.

The technology behind the IBM 990 was also notable for its use of solid-state technology. This provided a shift away from vacuum tube systems that were prevalent in earlier computing systems, enhancing the reliability and longevity of the hardware. The IBM 990 series utilized core memory, which was faster and more reliable than the magnetic drum memory systems that had been standard up to that point.

Another defining characteristic of the IBM 990 was its extensibility. Organizations could configure the machine to suit their specific needs by adding memory, storage, and peripheral devices as required. This modular approach facilitated the growth of systems alongside the technological and operational demands of the business environments they served.

In terms of software, the IBM 990 series was compatible with a variety of operating systems and programming environments, including FORTRAN and COBOL, enabling users to access a broader array of applications. This versatility was a significant advantage, making the IBM 990 an appealing choice for educational institutions, research facilities, and enterprises alike.

Moreover, the IBM 990 was engineered to support multiprocessing, which allowed multiple processes to run simultaneously, further increasing its effectiveness in tackling complex computing tasks.

In summary, the IBM 990 series represents a significant advancement in computing technology during the late 20th century. With a robust architecture, versatile configuration options, and a focus on solid-state technology, the IBM 990 facilitated substantial improvements in data processing capabilities, making it a cornerstone for many businesses and academic institutions of its time. Its impact can still be seen today in the continued evolution of mainframe computing.
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