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

6947ch06.fm

Dynamic activates for hardware changes

If a z990 processor running z/OSs with exploitation and compatibility support, and a new hardware configuration is to activated, the H/W activate must be done on one of the z/OS systems that run with exploitation support if both of the following conditions exist:

￿There is more than one Logical Channel Subsystem defined

￿A non-zero LCSS is being changed, or resources affected by the change are defined to non-zero CSSs

Dynamic CHPID management

On a z990, systems that are part of the same LPAR cluster may be in different LCSSs.

Dynamic CHPID management is supported even if the LPAR cluster spans multiple Logical Channel Subsystems. Movement of CHPIDs within the LPAR cluster is confined to movement within that LCSS, since ESCON channels cannot span multiple Logical Channel Subsystems.

If an LPAR cluster spans multiple LCSSs, then the DCM command VARY SWITCH must be issued from one of the systems with exploitation support. The DCM command SETIOS DCM=ON/OFF can be issued from any system, whether in compatibility mode or exploitation mode.

Greater than 15 logical partitions

You must define more than one LCSS if you plan to use more than 15 logical partitions. An individual Logical Channel Subsystem can only support up to 15 logical partitions.

In z/OS V1.2 and above and OS/390 V2.10, logical partitions running in compatibility mode can only reside in LCSS 0.

Coupling Facilities, z/VM V4R4 and follow-on releases, and Linux on zSeries can reside in any Logical Channel Subsystem.

6.3 z/VM software support

Compatibility support for z/VM on the z990 is provided for z/VM V3R1, and V4R3, It is available through the normal service stream for z/VM. See the appropriate PSP bucket.

z/VM Compatibility support is almost identical to that for z/OS in the function that it provides. The z990 compatibility support allows:

￿Support for up to four LCSSs

￿Dynamic I/O support for LCSS 0 only

￿Up to 15 Logical Partitions (LPAR identifiers < 15 (x’F’))

￿Internal and External spanned channels

For z/VM V4R4, and z/VM V5R1 Compatibility and Exploitation support is included. Some items of interest are:

￿Up to 30 Logical Partitions

￿Up to four LCSSs

￿Dynamic I/O support for LCSS 0, 1, 2, and 3

￿24 processors (all CPs or all IFLs) within a single logical partition (in z/VM 5.1 only).

–Note that the sum of initial and reserved processors for an ESA/390 mode logical partition can go up to 32 processors.

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IBM 990 manual Z/VM software support, Dynamic activates for hardware changes, Dynamic Chpid management
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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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