6947ch03.fm

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

3.1 Overview

The z990 I/O system design provides great flexibility, high availability and performance, allowing:

High bandwidth

The z990 I/O system can handle up to 96 GB/sec, which is four times the z900 server’s bandwidth. Individual channels can have up to 2 Gb/sec and individual Coupling Facility links up to 2 GB/sec data rates.

Wide connectivity

A z990 server can be connected to an extensive range of interfaces, using protocols such as Fibre Channel Protocol (FCP) for Small Computer System Interface (SCSI), Gigabit Ethernet (GbE), 1000BASE-T Ethernet, 100BASE-T Ethernet, 10BASE-T Ethernet, Token Ring along with FICON Express, ESCON and coupling links channels.

Cryptographic functions

The z990 I/O system also supports optional cryptographic cards to complement the standard CP Assist for Cryptographic Function (CPACF) that is implemented in every PU, enhancing the performance of cryptographic processing.

Concurrent I/O upgrades

It is possible to concurrently add I/O cards to a z990 server provided there are unused slot positions in an I/O cage. Additional I/O cages can be previously installed on an initial configuration, via CUoD, to provide greater capacity for concurrent upgrades. This capability may help eliminate an outage to upgrade the I/O configuration. See more information about concurrent upgrades on Chapter 8, “Capacity upgrades” on page 185.

Dynamic I/O configuration

Dynamic I/O configuration enhances system availability by supporting the dynamic addition, removal, or modification of channel paths, control units, I/O devices, and I/O configuration definitions to both hardware and software (if it has this support) without requiring a planned outage.

ESCON port sparing and upgrading

The ESCON 16-port I/O card includes one unused port dedicated for sparing in the event of a port failure on that card. Other unused ports are available for growth of ESCON channels without requiring new hardware, enabling concurrent upgrades via Licensed Internal Code (LIC).

The following I/O feature ports are supported in the zSeries 990 server:

￿Up to 1024 ESCON (up to 720 ESCON on model A08)

￿Up to 120 Fibre Connection (FICON) Express (up to 96 FICON on model A08)

￿Up to 48 Open Systems Adapter (OSA) Express

￿Up to 16 Integrated Cluster Bus-4 (ICB-4) (up to 12 ICB-4 on model A08)

￿Up to 16 Integrated Cluster Bus-3 (ICB-3)

￿Up to 8 Integrated Cluster Bus-2 (ICB-2)

￿Up to 48 Inter-System Channel-3 (ISC-3) in peer mode (up to 32 ISC-3 in compatibility mode)

￿Up to 2 External Time Reference (ETR)

Note: The maximum number of Coupling Links combined (IC, ICB-2, ICB-3, ICB-4, and active ISC-3 links) cannot exceed 64 per z990 server.

74IBM eServer zSeries 990 Technical Guide

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IBM 990 manual Overview
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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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