It depends on the microcode on your z/9 processor. Prior to a microcode upgrade, we were able to run OS/390 2.10 under z/VM. After the microcode upgrade, OS/390 2.10 would run very slowly under z/VM.
-----Original Message----- From: The IBM z/VM Operating System [mailto:IBMVM@LISTSERV.UARK.EDU] On Behalf Of Rob Holtz Sent: Friday, February 25, 2011 11:41 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: VSWITCH I realize that this is a year old but I am trying to get a definitive answer about the earliest release of z/OS that will successfully use a VSWITCH as a guest. We sometimes have to resurrect an old z/OS release to solve a customer issue. I have been successful with z/OS 1.4 but now we have a z/OS 1.3 issue and I can not get z/OS 1.3 to work with a VSWITCH. I was able to build a hipersocket VLAN and got the z/OS guest to work using that but am curious about the minimum level of z/OS that works with a VSWITCH. Our VM host is at z/VM 5.4 at RSU 1003 so it is current in so far as what can be run on a z/9 processor. Thanks, Rob
