> CMS is indeed an operating system. Early on it used to be able to run independently of z/VM, but that is no longer true.
I'm quite familiar architecturally with CMS. Yes, it is in one sense an operating system. If I drew a picture of z/VM with a bunch of guests, CMS would be a peer to VSE, z/OS and Linux, all of which are no-doubt-about-it operating systems. So yes, it must be an OS. It's a funny beast of an OS: a single-user operating system for a mainframe! OTOH, the way people use it it is more like a single TSO session than an operating system. It is more of a single-user terminal session than an OS. And yes, it no longer can be IPLed on the hardware, so a purist might say that disqualifies it as an operating system right there. What kind of operating system requires an operating system in order to run? Would not the proper phrase be "run independently of CP"? CMS is a component of z/VM; it can't be independent of z/VM, it *is* z/VM. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Mark Post Sent: Friday, February 10, 2017 1:26 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: IBM LinuxONE Rockhopper >>> On 2/10/2017 at 03:58 PM, Charles Mills <charl...@mcn.org> wrote: > Everything I know about Linux administration could be engraved on the > back of a postage stamp but I would think that if one were a pure > Linux sort of person then one would almost certainly use kvm for > Rockhopper virtualization, That is going to depend on just how hard you want to push your hardware. z/VM can support a whole lot more virtual machines than KVM can on any given mainframe box. I and various other people have repeatedly tried to get IBM to stop publicizing how many virtual machines can run on a fully loaded z13 with no indication of what hypervisor needed to be used for that. z/VM would have a hard time hitting that oft quoted 8,000 number. KVM as it stands today wouldn't even come close. (Note that I expect KVM to continue to improve in this area, but I'm talking about "today.") The people who are responsible for both z/VM and KVM on z are trying to do the right thing by positioning KVM as the "entry level" hypervisor for mainframe customers that don't have access to z/VM skills but do have Linux expertise. I don't know how many people are listening to them. Certainly IBM marketing isn't. > rather than learning another two OS's (counting CMS as an OS, which it > is in a sense). If one were coming from Linux on z/VM, one would > probably not want to give up all of the CMS niftiness. CMS is indeed an operating system. Early on it used to be able to run independently of z/VM, but that is no longer true. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
