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

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Additional token ring only wiring scenario

Additional connections to the token ring LAN may be made to expand the connectivity beyond the local Hardware Management Console and Support Elements, as shown in Figure A-4 on page 237.

If connections to previous generations of Enterprise Server systems are desired, they may be connected using the MAU in the system, or they may be connected using token ring-to-token ring bridges.

If connection to the enterprise LAN is desired, it is recommended that a token ring bridge be installed to isolate the Hardware Management Console and Support Elements from other systems.

If connection to a central site focal point is desired, a local control unit can be attached to the LAN.

zSeries 990

SE

SE

SE

SE

zSeries 990

Token-Ring LAN

Control

Unit

Bridge

S/390

Focal

Point

Enterprise

LAN

Figure A-4 Token ring only wiring with additional connections

Ethernet only - one-path wiring scenario

This Ethernet only wiring scenario is intended for enterprises that currently have Ethernet installed and do not want token ring wiring introduced into their environment. This wiring scenario requires that a second Ethernet be specified with the Support Elements, and that no token ring feature be ordered on the Hardware Management Console, such that no token ring exists in either the Support Elements or in the Hardware Management Console. (If your system is going to use FC 0075, this console is always equipped with a token ring-Ethernet communication capability. The token ring wrap plug shipped with the system must be installed in the Hardware Management Console token ring adapter to enable the console to operate properly without using token ring.)

Appendix A. Hardware Management Console (HMC) 237

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IBM 990 manual Ethernet only one-path wiring scenario, Additional token ring only wiring scenario
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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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