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

6947ch02.fm

￿An Internal Coupling Facility (ICF)

The number of CPs, IFLs, ICFs, zAAPs, or SAPs assigned to particular models depends on the configuration. The z990 12-PU MCMs have two SAPs as standard. The standard number of SAPs in a model A08 is two; there are four in a B16; six in a C24; and eight in a D32.

Optional additional SAPs may be purchased, up to two per book.

The z990 12-PU MCMs have two spares PUs as standard. The standard number of spares in a model A08 is two; there are four in a B16; six in a C24; and eight in a D32. The number of additional spare PUs is dependent on the number of books in the configuration and how many PUs are non-characterized.

Central Processors

A Central Processor is a PU that has the z/Architecture and ESA/390 instruction sets. It can run z/Architecture, ESA/390, Linux, and TPF operating systems, and the Coupling Facility Control Code (CFCC).

The z990 can only be used in LPAR mode. In LPAR mode, CPs can be defined as dedicated

or shared to a logical partition. Reserved CPs can be defined to a logical partition, to allow for non-disruptive image upgrades. The z990 can have up to 32 CPs.

All CPs within a z990 configuration are grouped into a CP pool. Any z/Architecture, ESA/390, Linux, and TPF operating systems, and CFCC can run on CPs that are assigned from the CP pool.

Within the limit of all non-characterized PUs available in the installed configuration, CPs can be concurrently assigned to an existing configuration via Capacity Upgrade on Demand (CUoD), Customer Initiated Upgrade (CIU), On/Off Capacity on Demand (On/Off CoD), or Capacity BackUp (CBU). More information about all forms of concurrent CP adds are found in “Capacity upgrades” on page 185.

If the MCMs in the installed books have no available PUs left, the assignment of the next CP may result in the need for a model upgrade and the installation of an additional book. Book installation is a non-disruptive action, but will take more time than a simple Licensed Internal Code upgrade. Only if reserved processors have been defined to a logical partition—and when the operating system supports the function—can additional CP capacity be allocated to the logical partition dynamically.

Integrated Facilities for Linux

An Integrated Facility for Linux (IFL) is a PU that can be used to run Linux on zSeries, Linux for S/390, or Linux guests on z/VM operating systems. Up to 32 PUs may be characterized as IFLs, depending on the z990 model. IFL processors can be dedicated to a Linux or a z/VM logical partition, or be shared by multiple Linux guests and/or z/VM logical partitions running on the same z990 server. Only z/VM, Linux on zSeries, and Linux for S/390 operating systems can run on IFL processors.

All PUs characterized as IFL processors within a configuration are grouped into the ICF/IFL/zAAP processor pool. The ICF/IFL/zAAP processor pool appears on the hardware console as ICF processors. The number of ICFs shown is the sum of IFL, ICF, and zAAP processors on the server.

IFLs do not change the software model number of the z990 server. Software product license charges based on the software model number are not affected by the addition of IFLs.

Chapter 2. System structure and design 47

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IBM 990 manual Central Processors, Integrated Facilities for Linux
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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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