6947ch02.fm

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

STI connectors

Book front view

MBA

LEDs

STI STI STI STI

)

 

Pins

FGA

 

Signal(720

 

MBA

 

 

ROW-6

SEEP

 

 

STI STI

STI

STI

 

VHDM

 

 

 

 

MBA

 

 

STI STI

STI

STI

MBA card

Figure 2-8 STI connectors and MBA card

Each book has three MBAs, each driving four STIs, resulting in 12 STIs per book.

All 12 STIs per book have a data rate of 2.0 GB/sec, resulting in a sustained bandwidth of 24 GB/sec per book. Consequently, the total instantaneous internal bandwidth of a four-book system is 4 x 24 GB/sec or 96 GB/sec. Depending on the channel types installed, a maximum of 512 channels per CPC is currently supported.

Four STIs are related to one MBA. When configuring for availability, you should balance channels, links, and OSAs across books, MBAs, and STIs. For z990, enhancements have been made such that, in the unlikely event of a catastrophic failure of an MBA chip, the failure is contained to that chip, while the other two MBAs on that book continue to operate. In a system configured for maximum availability, alternate paths will maintain access to critical I/O devices.

In the configuration reports, books are numbered 0, 1, 2, and 3, MBAs are numbered from 0 to 2, and the STIs are identified as jacks numbered from J.00 to J.11.

Book upgrade

As a result of a concurrent book upgrade, additional MBA and STIs connectors become available. Since now more external connections to the I/O are potentially available, there may be circumstances in which it might be beneficial to rebalance the total I/O configuration across all available MBA/STIs.

Not all book upgrades will necessitate a rebalance of the I/O configuration, since the number of STIs of the original configuration may well be able to service all existing I/O in an efficient and balanced way.

However, if the result of the upgrade is an unbalanced I/O configuration, you should consider rebalancing the configuration by using the additional MBA/STIs. An I/O distribution over books, MBAs, STIs, I/O cages and I/O cards is often desirable for both performance and

32IBM eServer zSeries 990 Technical Guide

Page 45 Page 47
Page 46
Image 46
IBM 990 manual Book upgrade, STI connectors Book front view
Page 45 Page 47

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.
Top Page Image Contents