6947ch01.fm

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

ICB-2 (Integrated Cluster Bus 2)

The Integrated Cluster Bus-2 (ICB-2) link is a member of the family of Coupling Link options available on z990. Like the ISC-3 link, it is used by coupled systems to pass information back and forth over high speed links in a Parallel Sysplex environment. ICB-2 or ISC-3 links are used to connect 9672 G5/G6 to z990 servers.

An STI-2 resides in the I/O cage and provides two output ports to support the ICB-2 connections. The STI-2 card converts the 2 GB/sec input into two 333 MB/sec ICBs. The ICB-2 is defined in compatibility mode and the link speed is 333 MB/sec.

One feature is required for each end of the link. Ports are ordered in increments of one.

ICB-3 (Integrated Cluster Bus 3)

The Integrated Cluster Bus-3 (ICB-3) link is a member of the family of Coupling Link options available on z990. Like the ISC-3 link, it is used by coupled systems to pass information back and forth over high speed links in a Parallel Sysplex environment. ICB-3 or ISC-3 links are used to connect z900, z800, or z890 servers (2064, 2066, or 2086) to z990. servers.

An STI-3 card resides in the I/O cage and provides two output ports to support the ICB-3 connections. The STI-3 card converts the 2GB/sec input into two 1 GB/sec ICBs. The ICB-3 is defined in peer mode and the link speed is 1 GB/sec.

One feature is required for each end of the link. Ports are ordered in increments of one.

ICB-4 (Integrated Cluster Bus 4)

The Integrated Cluster Bus-4 (ICB-4) link is a member of the family of Coupling Link options available on z990. ICB-4 is a “native” connection used between z990 and or z890 processors. An ICB-4 connection consists of one link that attaches directly to an STI port in the system, does not require connectivity to a card in the I/O cage, and operates at 2 GB/sec. The ICB-4 works in peer mode and the link speed is 2 GB/sec.

One feature is required for each end of the link. Ports are ordered in increments of one.

Internal Coupling (IC)

The Internal Coupling-3 (IC) channel emulates the Coupling Facility functions in LIC between images within a single system. No hardware is required; however, a minimum of two CHPID numbers must be defined in the IOCDS for each connection.

System-Managed CF Structure Duplexing

System-Managed Coupling Facility (CF) Structure Duplexing provides a general purpose, hardware-assisted, easy-to-exploit mechanism for duplexing CF structure data. This provides a robust recovery mechanism for failures (such as loss of a single structure or CF or loss of connectivity to a single CF) through rapid failover to the other structure instance of the duplex pair.

The following three structure types can be duplexed using this architecture:

￿Cache structures

￿List structures

￿Locking structures

Support for these extensions is included in Coupling Facility Control Code (CFCC) Levels 11 12, and 13 and in z/OS V1.2, V1.3, V1.4, and V1.5 and later.

14IBM eServer zSeries 990 Technical Guide

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IBM 990 ICB-2 Integrated Cluster Bus, ICB-3 Integrated Cluster Bus, ICB-4 Integrated Cluster Bus, Internal Coupling IC
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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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