Operating system support, Z/OS software support

6947ch06.fm

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

6.1 Operating system support

There are many significant changes in the z990 architecture and hardware features when compared to the z900 processor. Extensive software support has been made available to existing OS levels via compatibility and exploitation support to accommodate these changes in the OS/390, z/OS, z/VSE, VSE/ESA, TPF, z/VM and Linux on zSeries operating systems. Table 6-1summarizes supported software on the z990.

Table 6-1 z990 software support summary

Operating system	ESA/390	z/Arch.	Compatibility	Exploitation
	(31-bit)	(64-bit)

OS/390® Version 2 Release 10	Yes	Yes	Yes	No

z/OS Version 1 Release 2	Noa	Yes	Yes	No
z/OS Version 1 Release 3	Noa	Yes	Yes	No
z/OS Version 1 Release 4	Noa	Yes	Yes	Yes
z/OS Version 1 Release 5 and 6b	No	Yes	Included	Included
Linux for S/390	Yes	No	Yes	Yes

Linux® on zSeries	No	Yes	Yes	Yes

z/VM Version 3 Release 1	Yes	Yes	Yes	No

z/VM™ Version 4 Release 3	Yes	Yes	Yes	No

z/VM Version 4 Release 4	Yes	Yes	Included	Included

z/VM Version 5 Release 1	No	Yes	Included	Included

VSE/ESA™ Version 2	Yes	No	Yes	Yes
Release 6 and 7

z/VSE Version 3 Release 1c	Yes	No	Included	Included
TPF Version 4 Release 1	Yes	No	Yes	No
(ESA mode only)

a. 31-bit mode is only available as part of the z/OS Bimodal Migration Accommodation software program. The program is intended to provide fallback support to 31-bit mode in the event that it is required during migration to z/OS in z/Architecture mode (64-bit).

b. z/OS 1.6 planned to be available September 2004.

c. The z/VSE operating system can execute in 31-bit mode only. It does not implement z/Archi- tecture, and specifically does not implement 64-bit mode capabilities. The z/VSE operating sys- tem is designed to exploit select features of IBM eServer zSeries hardware.

6.2 z/OS software support

z/OS software support has been designed at two levels: Compatibility support and Exploitation support.

6.2.1 Compatibility support for z/OS

Compatibility support for z/OS software is delivered in several ways depending on the version of release of z/OS.

134IBM eServer zSeries 990 Technical Guide

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.

IBM 990 manual Operating system support, Z/OS software support, Compatibility support for z/OS

Models: 990

6.1 Operating system support

6.2 z/OS software support

6.2.1 Compatibility support for z/OS

990 specifications