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

6947ch03.fm

Note: Mode Conditioning Patch (MCP) cables are for use with 1 Gbit/sec (100 MB/sec) links only.

Multimode (62.5 or 50 micron) fiber optic cable may be used with the z990 FICON Express LX feature for 1 Gbps only. The use of this multimode cable type requires a Mode Conditioning Patch (MCP) cable to be used at each end of the fiber optic link, or at each optical port in the link. Use of the single-mode to multimode MCP cables reduces the supported optical distance of the 1 Gbps link to an end-to-end maximum of 550 meters.

Fiber optic conversion kits and Mode Conditioning Patch (MCP) cables are not orderable as features on z990. Fiber optic cables, cable planning, labeling, and installation are all customer responsibilities for new z990 installations and upgrades.

IBM Fiber Cabling Services offer total a cable solution service to help with your cable ordering needs, and is highly recommended.

FICON Express SX feature

The z990 FICON Express SX feature (feature code 2320) occupies one I/O slot in the z990 I/O cage. The feature has two Peripheral Component Interconnect cards. Each PCI card has a single port supporting an LC Duplex connector, with one PCHID associated with each port, and supports link speeds of 1Gbps and 2 Gbps.

Each port supports attachment to the following:

￿Fibre Channel Switch that supports 1Gbps/2Gbps Fibre Channel/FICON SX

￿Control unit that supports 1Gbps/2Gbps Fibre Channel/FICON SX

Each port of the z990 FICON Express SX feature uses an 850 nanometer (nm) fiber bandwidth transceiver. The port supports connection to a 62.5 micron or 50 micron multimode fiber optic cable terminated with an LC Duplex connector.

FICON channel in Fibre Channel Protocol (FCP) mode

When configured for FCP mode, the FICON Express features can access FCP devices either:

￿Via a FICON channel in FCP mode through a single Fibre Channel switch or multiple switches to an FCP device

￿Via a FICON channel in FCP mode through a single Fibre Channel switch or multiple switches to a Fibre Channel-to-SCSI bridge

Note: z990 FCP channel direct attachment in point-to-point and arbitrated loop topologies is not supported as part of the zSeries FCP enablement.

z990 adapter interruptions enhancement for FCP

The z990 servers, Linux for zSeries, and z/VM work together to provide performance improvements by exploiting extensions to the Queued Direct Input/Output (QDIO) architecture. Adapter Interruptions, first added to z/Architecture with HiperSockets, provide an efficient, high-performance technique for I/O interruptions to reduce path lengths and overhead in both the host operating system and the adapter - FICON Express, when using the FCP CHPID type.

In extending the use of adapter interruptions to FCP channels, the programming overhead to process a traditional I/O interruption is reduced. This benefits FCP support in Linux for zSeries.

Chapter 3. I/O system structure

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IBM 990 manual Ficon channel in Fibre Channel Protocol FCP mode, Ficon Express SX feature
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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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