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

6947ch02.fm

￿The IBM 2084 model D32 has four books (D) with 12 PUs in each book for a total of 48 PUs, of which 32 can be characterized by the customer. The remaining PUs are eight system assist processors (SAPs) and eight spares, two of each in each book.

The last two digits of the model number reflect the maximum number of PUs that can be characterized for installation use. The PUs can be characterized as CPs, IFLs, ICFs, zAAPs or additional SAPs. The characters A, B, C, and D in the model number reflect the number of books installed.

Whether one, two, three, or four books are present, to the user all books together appear as one Symmetric Multi Processor (SMP) with a certain number CPs, IFL, ICFs, and zAAPs a certain amount of memory, and bandwidth to drive the I/O channels and devices. The packaging is designed to scale to a 32-PU Symmetric Multi-Processor (SMP) server in four books.

2.1.3 Memory

Maximum physical memory sizes are directly related to the number of books in the system. Each book may contain a maximum of 64 GB physical memory. The amount of memory on each of the two memory cards in a book must be the same. The memory sizes in each book do not have to be similar; different books may contain different amounts of memory. The minimum orderable amount of memory is 16 GB, system-wide.

￿A one-book system (IBM 2084-A08) may contain 16 GB, 32 GB or 64 GB of physical memory. Memory is orderable in 8 GB increments for customer use.

￿A two-book system (IBM 2084-B16) may contain up to a maximum of 128 GB of physical memory. For all memory card distribution variations in a newly built two-book systems, refer to Table 2-1 on page 28. Memory is orderable in 8 GB increments for customer use.

￿A three-book system (IBM 2084-C24) may contain up to a maximum of 192 GB of physical memory. For some memory card distribution variation in a newly built three-book system, refer to Table 2-1 on page 28. Memory is orderable in 8 GB increments for customer use.

￿A four-book system (IBM 2084-D32) may contain up to a maximum of 256 GB of physical memory. For some memory card distribution variation in a newly built four-book system, refer to Table 2-1 on page 28. Memory is orderable in 8 GB increments for customer use.

The system physical memory is the sum of all book memories. Not all books need to contain the same amount of memory, and not all installed memory is necessarily configured for use.

Memory Sizes

The minimum orderable amount of usable memory for all models is 16 GB. Memory upgrades are available in 8 GB increments:

￿IBM 2084 Model A08, from 16 to 64 GB

￿IBM 2084 Model B16, from 16 to 128 GB

￿IBM 2084 Model C24, from 16 to 192 GB

￿IBM 2084 Model D32, from 16 to 256 GB

Physically, the memory cards are organized as follows:

￿Each book always contains two memory cards. A memory card can come in three sizes:

–8 GB

–16 GB

–32 GB

￿Within a given book the card sizes must be equal, but all books do not necessarily need to have the same amount of physical memory installed.

Chapter 2. System structure and design 27

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IBM 990 manual Memory Sizes
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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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