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

6947ch06.fm

of logical partitions and logical CPs, these records could potentially increase in size beyond the 32 KB limit.

To accommodate this, each record is now broken into pieces where each piece is shorter than 32KB. Each piece is self-containing; that is, the record can be processed without re-assembling the broken pieces. If you have any site-specific processing of this data outside of RMF, you may need to review that application to ensure that it is no longer dependent upon all this data being contained within a single record.

RMF Monitor 1 Device Activity reporting is recorded in the SMF 74, subtype 1 records. These have been updated to support an extended device data section. This section now includes the Initial Command Response time for the device. A similar change has also been made to the RMF Monitor II Device Activity recording in the SMF 79, subtype 9 records.

The SMF records for the SRM Decisions data stored in type 99, (subtypes 8 and 9) have also been extended. These records now contain the LCSS id for the WLM LPAR management and I/O subsystem information.

6.2.6 RMF support

There are several changes to RMF reports to accommodate the enhanced I/O subsystem and improved collection of channel measurement data.

The I/O Activity report no longer shows the Control Unit Busy (CUB) and Director Port Busy (DPB) times. (The corresponding percentage and pending reason fields for CUB and DPB have also been removed from the Monitor III reports). This information was already available at an LCU level anyway and is much more useful than the figures being broken out for individual devices.

Furthermore, the Director Port Busy field would only show a non-zero value for the events when all director ports were busy. If an individual director port was found to be busy but a connection was established through an alternate path, then this figure was not updated. With FICON connections, a Director Port was never reported busy since that type of channel allows multiple data transfers to occur simultaneously.

A better measure of fabric contention has now been provided with the Initial Command Response Time. This is a measure of the time taken from sending a command to a device, to it responding that it has accepted the command. This new metric (AVG CMR DLY) has now replaced the older AVG CUB and AVG DPB columns on the Monitor I Device Activity Report. Corresponding DELAY CMR% and PENDING REASON CMR displays have been introduced into the Monitor III reports. Monitor III exception reporting has also been updated to replace the previous CUBDL and DPBDL conditions with the new condition, CMRDL.

6.2.7 ICKDSF requirements

ICKDSF Release 17 is required on all systems that share DASD with a z990 processor.

ICKDSF 17 supports the new format of the CPU information field, which now contains a two-digit LP identifier. ICKDSF uses the CPU information field instead of CCW reserve/release for concurrent media maintenance. It prevents multiple systems from running ICKDSF on the same volume, and at the same time allows user applications to run while ICKDSF is processing. In order to prevent any possible data corruption, ICKDSF must be able to determine all sharing systems that may potentially run ICKDSF; therefore, this support is required for z990.

Chapter 6. Software support 141

Page 154 Page 156
Page 155
Image 155
IBM 990 manual RMF support, Ickdsf requirements
Page 154 Page 156

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