6947ch01.fm

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

1.3.17 Summary

On a physical resource level, z990 is a S/390 architecture server with a maximum of 48 PUs and 256 GBytes of main memory structured in a four-book configuration. The books are interconnected by a high speed memory coherence ring, thus building a large and very efficient SMP. The I/O adapters are housed in three I/O cages, and provide a maximum of 1024 (maximum 256 per LCSS) channel ports.

The z900 to z990 is a “Frame Roll” MES. The z990 A and Z frames are shorter and deeper than z900's frames, actually taking up less space than the z900. The z900 I/O cards, 16-port ESCON, FICON Express, PCICA and OSA Express, will move to different I/O slots in the new z990 system I/O cages.

PR/SM handles these physical resources as one contiguous space and provides, on a logical level, up to 30 logical partitions and up to four Logical Channel Subsystems with 256 channel paths each. Thus, a large and scalable physical resource pool is generated, managed by PR/SM in a highly efficient way, taking advantage of LPAR clustering.

Dynamic CHPID management and I/O priority queuing were introduced with z900. These capabilities are extended to support Linux (for S/390 and on zSeries) partitions with the same efficiency. Since the maximum number of supported logical PUs within a partition is 24 (z/OS V1.6, and z/VM V5.1 plan to have support for up to 24 processors in a single LPAR), multiple copies of operating systems (z/OS and Linux) run “side-by-side” on the same hardware platform. z990 also continues to support the latest Ethernet technology, to provide the highest bandwidth connections to external servers.

22IBM eServer zSeries 990 Technical Guide

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IBM 990 manual Summary
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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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