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

6947ch03.fm

A maximum of 1024 ESCON ports can be activated on a z990 server. This maximum requires sixty-nine16-port ESCON channel cards to be installed. The z990 model A08 can have up to 720 ESCON ports, on 48 channel cards, which is limited by the number of STIs available on the A08 model.

16-port ESCON channel sparing

The last ESCON port on a 16-port ESCON channel card (normally J15) is assigned as a spare port. Should an LIC-CC-enabled ESCON port on the card fail, the spare port is used to replace it, as shown in Figure 3-11 on page 95.

If the initial first spare port (J15) is already in use and a second LIC-CC-enabled port fails, then the highest LIC-CC-protectedport (for instance, J14) is used to spare the failing port.

 

110

 

Failure

120

110

 

 

 

120

 

J00

J00

J00

 

J00

111

 

121

111

 

121

 

J01

J01

J01

 

J01

 

112

122

 

 

122

113

J02

J02

113

J02

 

J02

 

J03

J03

123

J03

 

J03

123

 

 

 

 

 

 

J04

J04

 

 

J04

 

J04

 

 

 

J05

J05

 

 

J05

Sparing

J05

 

PCHID

J06

J06

 

 

J06

J06

 

J07

J07

 

 

J07

J07

 

Number

C

 

 

 

 

J08

J08

H

 

J08

J08

 

 

 

S A

 

 

 

 

 

 

 

P

 

 

Channel

 

 

 

 

J09

J09

AN

 

J09

J09

 

 

 

RN

 

 

 

 

J10

J10

I E

 

J10

J10

 

 

 

N L

 

 

 

 

G

 

 

 

 

J11

J11

 

 

J11

J11

 

 

 

 

 

 

 

 

 

J12

J12

 

 

J12

 

J12

 

 

 

J13

J13

 

 

J13

 

J13

 

 

 

J14

J14

 

112

J14

 

J14

 

 

 

J15

J15

 

 

J15

 

J15

 

 

 

ESCON-16

 

ESCON-16

 

ESCON-16

 

 

ESCON-16

 

 

 

 

 

 

 

 

 

 

 

SPARE

 

 

 

SPARE

 

 

 

 

 

CHANNELS

 

 

 

CHANNEL

 

Figure 3-11 16-port ESCON channel sparing

Channel port sparing can only occur between ports on the same 16-port ESCON card. That is, a failing ESCON channel port cannot be spared with another port on a different 16-port ESCON card.

Channel sparing is a service repair action performed by an IBM service representative (SR) using the z990 server maintenance package Repair and Verify procedure. If sparing can take place, the IBM SR moves the external fiber optic cable from the failing port to the spare port. When sparing occurs, the PCHID moves to the spare port (PCHID 112 in Figure 3-11). If sparing cannot be performed, the 16-port ESCON card is replaced.

Fiber Quick Connect (FQC) for ESCON “Quick Connect”

The Fiber Quick Connect (FQC) features are optional features for factory installation of the IBM Fiber Transport System (FTS) fiber harnesses for connection to ESCON channels in the I/O cage. Each direct-attach fiber harness connects to six ESCON channels at one end and one coupler in a Multi-Terminated Push-On Connector (MTP) coupler bracket at the opposite end. When ordered, the features support all of the installed ESCON features in all of the installed I/O cages. FQC cannot be ordered on a partial or one cage basis.

Chapter 3. I/O system structure

95

Page 109
Image 109
IBM 990 manual Fiber Quick Connect FQC for Escon Quick Connect, Port Escon channel sparing

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.