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

Important: The z890 and z990 will be the last zSeries servers to offer Token Ring adapter features on the Hardware Management Consoles (HMCs), Support Element (SEs), and Trusted Key Entry (TKE) workstations. The IBM 2074 Model 3 Console Support Controller will be the last controller to offer Token Ring adapter features.

IBM zSeries is making these statements to allow enterprises sufficient opportunity to prepare for a migration to Ethernet environments.

Notes on wiring with multiple adapters:

￿It is intended that a Hardware Management Console and the SE together be connected by only one LAN.

￿Multiple adapters in a Hardware Management Console allow that Hardware Management Console to connect with two independent sets of SEs: one set on a token ring and a second set on an Ethernet.

This is done to allow for migration from token ring environments to Ethernet environments.

￿Multiple adapters in a ThinkPad® SE are intended to allow two different Hardware Management Consoles to have independent paths to the SE.

This is done so that the console can be controlled if one LAN goes down.

In the following sections, we describe the four wiring scenarios.

Token ring only wiring scenario

The token ring only wiring scenario, shown in Figure A-4,is the standard wiring approach used in previous generations of the IBM Enterprise Server Hardware Management Console and Support Element wiring. As in previous systems, each system includes a Multistation Access Unit (MAU) that may be used to interconnect the token ring adapter wiring of the Support Elements to the Hardware Management Console. Token ring wiring may be used to interconnect the MAUs to form a larger private LAN where multiple systems are to be controlled by a single Hardware Management Console.

Token-Ring LAN

Primary

SE

Alternate

SE

z990

Figure A-3 Token ring only wiring scenario

236IBM eServer zSeries 990 Technical Guide

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IBM 990 manual Token ring only wiring scenario, Token-Ring LAN

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.