6947ch02.fm

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

2.The Motor Scroll Assembly (MSA)

3.The Motor Drive Assembly (MDA)

–MDAs are found throughout the frames to provide air cooling where required. They are located at the bottom front of each cage, and in between the CEC cage and I/O cage 1 in combination with the MSAs.

Hybrid cooling system

The z990 has a hybrid cooling system that is a breakthrough in lowering power consumption. Normal cooling is provided by one or two MRUs connected to the heat sinks of all MCMs in all books.

If one of the MRUs fails, backup MSAs are switched in to compensate for the lost refrigeration capability with additional air cooling. At the same time, the oscillator card will be set to a slower cycle time, slowing the system down by up to 8% of its maximum capacity, to allow the degraded cooling capacity to maintain the proper temperature range. Running at a slower cycle time, the MCMs will produce less heat. The slowdown process is done in steps, based on the temperature in the books.

Figure 2-3shows the refrigeration scope of MRU0 and MRU1.

MRU 0

 

 

MRU 1

Book 3

Book 0

Book 1

Book 2

Figure 2-3 MRU scope

2.1.2 Models

The z990 has four orderable models. The model numbers are directly related to the number of books in the system and the maximum number of PUs that can be characterized by the installation. For customer use, PUs can be characterized as CPs, IFLs, ICFs, zAAPs, or if need be, additional SAPs.

￿The IBM 2084 model A08 has one book (A) with 12 PUs, of which eight can be characterized by the customer. The four remaining PUs are two system assist processors (SAPs) and two spares.

￿The IBM 2084 model B16 has two books (B) with 12 PUs in each book for a total of 24 PUs, of which 16 can be characterized by the customer. The four remaining PUs are four system assist processors (SAPs) and four spares, two of each in each book.

￿The IBM 2084 model C24 has three books (C) with 12 PUs in each book for a total of 36 PUs, of which 24 can be characterized by the customer. The remaining PUs are six system assist processors (SAPs) and six spares, two of each in each book.

26IBM eServer zSeries 990 Technical Guide

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IBM 990 manual Models, Hybrid cooling system
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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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