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

6947ch02.fm

Power

Each book get its power from two Distributed Converter Assemblies (DCA) that reside on the opposite side of the CEC board. The DCAs provide the required power for the book. Each book is supported by two DCAs. The N+1 power supply design means that there is more DCA capacity than is required for the book. If one DCA fails, the power requirement for a book can still be satisfied from the remaining DCA. The DCAs can be concurrently maintained, which means that replacement of one DCA can be done without taking the book down.

Between two sets of DCAs you find the location of the oscillator cards (OSC) and the optional external time reference cards (ETR). If installed, there are two ETR ports to which an optional Sysplex Timer® can be connected. Seen from the top, the packaging of a four-book system appears as shown schematically in Figure 2-2.

Book3

Book0

Book1

Book2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Memory Cards

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Memory Cards

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Memory Cards

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Memory Cards

 

 

MCM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DCA30

DCA31

DCA00

DCA01

2xOSC 00/01 2xETR 00/01

DCA10

DCA11

DCA20

DCA21

Figure 2-2 Book and power packaging (top view)

Located within each book is a card on which the Memory Bus Adapters (MBAs) are located. The card has three MBAs, each driving four STIs (see Figure 2-8 on page 32).

Figure 2-2also illustrates the order of book installation:

￿In a one-book model, only book 0 is present.

￿A two-book model has books 0 and 1.

￿A three-book model has books 0, 1, and 2.

￿A four-book model has books 0, 1, 2, and 3.

Book installation to up to four books can be concurrent.

Cooling

The z990 is an air-cooled system assisted by refrigeration. Refrigeration is provided by a closed-loop liquid cooling subsystem. The entire cooling subsystem has a modular construction. Its components and functions are found throughout the cages, and are made up of three subsystems:

1.The Modular Refrigeration Units (MRU)

–One or two MRUs (MRU0 and MRU1), located in the front of the A-cage above the books, provide refrigeration to the content of the books together with Motor Drive Assemblies in (MDAs) in the rear.

–A one-book system has MRU0 installed. Upgrading to a two-book system causes MRU1 to be installed, providing all refrigeration needs for a four-book system. Concurrent repair of an MRU is possible by taking advantage of the hybrid cooling implementation described in the next section.

Chapter 2. System structure and design 25

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Image 39
IBM 990 manual Power, Cooling
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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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