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

6947ch07.fm

CPs are processor units used to process z/OS, OS/390, CFCC, z/VM, Linux, TPF, VSE/ESA, or z/VSE instructions. The logical partition can use dedicated or shared CPs. However, it is not possible to have a logical partition with dedicated and shared CPs at the same time.

ICFs are PUs dedicated to process the CF Control Code (CFCC) on a Coupling Facility image, which is always running on a logical partition. A CF image can use dedicated and/or

shared ICFs. It can also use dedicated or shared CPs. With Dynamic ICF Expansion, a Coupling Facility image can also use dedicated ICFs and shared CPs.

The z990 can have ICF processors defined to CF Images.

A z990 server Coupling Facility image can have one of the following defined in the image profile:

￿Dedicated ICFs

￿Shared ICFs

￿Dedicated and shared ICFs

￿Dedicated CPs

￿Shared CPs

￿Dedicated ICFs and shared CPs

Shared ICFs add flexibility. However, running with shared Coupling Facility processor units (ICFs or CPs) adds overhead to the coupling environment and is not a recommended production configuration.

In Figure 7-4, the server on the left has two environments defined (Production and Test), each having one z/OS and one Coupling Facility image. The Coupling Facility images are sharing

the same ICF processor. The logical partition Processing Weights are used to define how much processor capacity each Coupling Facility image can have. The Capped option can also

be set for the Test Coupling Facility Image, to protect the production environment. Connections between these z/OS and Coupling Facility images can use IC channels to avoid the use of real (external) coupling channels and to get the best link bandwidth available.

Test Sysplex

 

ICF

 

CP

z/OS

z/OS

CF

CF

z/OS

z/OS

CF

 

 

 

 

 

 

Test

Prod

 

 

Test

Prod

 

z990

Partition

Image Profile

HMC

Function

Setup

Figure 7-4 z990 ICF options - Shared ICFs

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IBM 990 manual Function Setup
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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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