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

attached to either LAN is able to automatically discover the Support Elements, assuming that the LAN network allows NetBios to flow between the devices (allowing NetBios to flow is a requirement for local HMC-to-SE communication, but it is not a requirement for remote HMC-to-SE communication).

HMC

HMC

SE

SE

zSeries 990

Figure A-7 Ethernet only - two-path wiring scenario

Additional connections to the Ethernet LAN

These may be made to expand the connectivity beyond the local HMC and SE (not applicable to systems with FC 0075).

This scenario is shown in Figure A-8.If connections to previous generations of Enterprise Server systems are desired, they may be connected using Ethernet-to-token ring bridges.

If connection to the enterprise LAN is desired, it is recommended that an Ethernet bridge or router be installed to isolate the HMC and SE from other systems.

240IBM eServer zSeries 990 Technical Guide

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IBM 990 manual Figure A-7 Ethernet only two-path wiring scenario

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.