134 IBM ^ zSeries 990 Technical Guide
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 6-1 summarizes supported software on the z990.
Table 6-1 z990 software support summary
6.2 z/OS software support
z/OS software support has been designed at two levels: Compatibility Support and
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.
Operating system ESA/390
OS/390® Version 2 Release 10 Yes Yes Yes No
z/OS Version 1 Release 2 No
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).
Ye s Ye s N o
z/OS Version 1 Release 3 No
Ye s Ye s N o
z/OS Version 1 Release 4 No
Ye s Ye s Ye s
z/OS Version 1 Release 5 and 6
b. z/OS 1.6 is planned to be available in September 2004.
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
Release 6 and 7
Ye s N o Ye s Ye s
z/VSE Version 3 Release 1
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
^ zSeries hardware.
Yes No Included Included
TPF Version 4 Release 1
(ESA mode only)
Ye s N o Ye s N o